{{Language_sel|LANG=ger|ARTIKEL=Risswiderstandskurve – Beispiele}}
{{PSM_Infobox}}
Crack resistance curve – Examples
__FORCETOC__

==General information==

The [[Toughness|toughness]] of [[Plastics|plastics]] is characterised on the basis of the [[Crack Resistance (R) Curve|crack resistance (R) curve]] concept; where the [[Material & Werkstoff|material]] exhibits elastic-plastic behaviour, the stages of the entire fracture process—crack blunting, stable [[Crack Initiation|crack initiation]], stable [[Crack Propagation|crack propagation]], and, following this, often unstable crack propagation and [[Fracture|fracture]] — can be described.

==R-curve for isotactic polypropylene (PP)==

Using isotactic polypropylene ([[Plastics – Symbols and Abbreviated Terms|abbreviation]]: PP) as an example, this paper demonstrates the possibility of characterising structural modifications (see also: [[Microscopic Structure|microscopic structure]]) caused by nucleation in PP materials [1].

To experimentally determine the [[Crack Resistance (R) Curve|crack resistance curves]] as a basis for establishing the [[Fracture Mechanical Testing|fracture mechanics parameters]] of [[Crack Initiation|crack initiation]] and [[Crack Propagation|crack propagation]], the [[Quasi-static Test Methods|quasistatic tensile test]] was employed using [[SENT-Specimen|SENT]] (Single-Edge-Notched Tension) specimens [2–6].

The addition of nucleating agents influences the structure of PP. Semi-crystalline PP is polymorphic, i.e. it can crystallise into the α, β or γ modification depending on the cooling conditions and the nucleation process. The α-modification is characterised by a helical structure in a monoclinic unit cell, which is the thermodynamically most stable form and thus the most common modification. In comparison, the β modification is less ordered and hexagonal, featuring non-parallel, crossed lamellae. The orthorhombic γ modification can be induced under high pressure or by the use of a nucleating agent [7–9]. The crystal modification influences the fundamental mechanical properties due to its different physical and mechanical properties [8, 9]. PP with a predominant β-modification has a lower [[Elastic Modulus|modulus of elasticity]] and [[Yield Stress|yield stress]] at a comparable [[Strain Rate Basics|strain rate]], but increased [[Impact Test|impact strength]], tensile strain at break [7] and higher [[Crack Toughness|crack toughness]] [10] compared with PP with an α-modification. The crystal structure can be influenced, amongst other things, by the addition of nucleating agents or by the cooling rate.

The isotactic PP was blended with an α-nucleating agent (αPP) or a β-nucleating agent (βPP). The plastics were cooled at a rate of 1 K/min (abbreviated as -1) and moulded into sheets (see also [11, 12]). The [[Crack Resistance (R) Curve|crack resistance curves]] (R-curves) of the various [[Plastics|plastics]] were evaluated in accordance with the procedure set out in ESIS TC4 [13].

{|
|<div style="display: block; text-align: center;" width="600" height="500">[[File:Crack_Resistance_Curve_-_Examples_Fig1-1.jpg|400px]]</div>
|-
|<div style="display: block; text-align: center;" width="600" height="500">[[File:Crack_Resistance_Curve_-_Examples_Fig1-2.jpg|550px]]</div>
|}
{|
|- valign="top"
|width="50px"|'''Fig. 1''':
|width="600px"|(a) R-curves for the plastics PP-1 and αPP-1, and (b) a typical [[Fracture Surface|fracture surface]] of a test specimen showing a metal-blade notch (1), stable crack propagation (2), the damaged zone (3) and the brittle fracture surface (4)
|}

==Effect of nucleation on polypropylene (PP)==

The R-curves for the three PP materials with different nucleation types are shown in '''Fig. 1a'''. At small stable crack extensions, the differences are relatively minor. At higher stable crack extensions, clear differences emerge between the non-nucleated PP-1 and the two nucleated types. For a comparable stable crack extension Δa, the J-values of αPP-1 and βPP-1 are significantly higher, although there is no significant difference between the two nucleated PP types.

This shows that, at a cooling rate of 1 K/min, the resistance of nucleated PP materials to stable [[Crack Propagation|crack propagation]] is higher than that of non-nucleated PP. A typical [[Fracture Surface|fracture surface]] of a PP material is shown in '''Fig. 1b'''. The metal blade notch, the zone of stable crack growth—characterised by a very [[Fracture Mirror|smooth surface]] and a clear boundary with the damage zone—and the residual fracture surface can be seen.

==See also==

* [[Fracture Mechanics|Fracture mechanics]]
* [[Crack Resistance (R) Curve|Crack resistance (R) curve]]
* [[Crack Resistance Curve – Experimental Methods|Crack resistance curve – Experimental methods]]
* [[Crack Resistance Curve – Elastomers Quasistatic|Crack resistance curve – Elastomers quasistatic]]
* [[Tearing Modulus|Tearing modulus]]

==References==

{|
|-valign="top"
|[1]
|Monami, A., Langer, B., [[Grellmann,_Wolfgang|Grellmann, W.]]: Moderne Methoden der Kunststoffprüfung zur Werkstoffentwicklung und Bauteilprüfung. Werkstoffprüfung. Fortschritte in der Werkstoffprüfung für Forschung und Praxis (2016), December 1 and 2, 2016, Neu-Ulm, Proceedings pp. 233–238 (ISBN 978-3-514-00830-4)
|-valign="top"
|[2]
|[https://www.researchgate.net/profile/Wolfgang-Grellmann Grellmann, W.], [[Reincke,_Katrin|Reincke, K.]], Monami, A., Kretzschmar, B.: Bruchmechanische Zähigkeitscharakterisierung von schichtsilikatverstärktem Polypropylen. In: [https://de.wikipedia.org/wiki/Michael_Pohl_(Metallurg) Pohl, M.] (Eds.): Konstruktion, Qualitätssicherung und Schadensanalyse. Stahleisen, Düsseldorf (2007), pp. 115−120 (ISBN 978-3-514-00753-6)
|-valign="top"
|[3]
|[https://de.wikipedia.org/wiki/Wolfgang_Grellmann Grellmann, W.], Langer, B., [[Bierögel,_Christian|Bierögel, C.]], Schoßig, M., Mecklenburg, T.: Bruchmechanische Zähigkeitsbewertung nukleierter glasfaserverstärkter Polyolefinwerkstoffe. In: Pohl, M. (Eds.): Konstruktion, Qualitätssicherung und Schadensanalyse, Publishing House Werkstoff-Informationsgesellschaft mbH, Frankfurt (2004) pp. 321−326 (ISBN 3-88355-337-9)
|-valign="top"
|[4]
|Kroll, M., Langer, B., Grellmann, W.: Toughness optimization of elastomer-modified glass-fiber reinforced PA6 materials. Journal of Applied Polymer Science 127 (2013) 57−66 DOI: [https://doi.org/10.1002/app.36853 https://doi.org/10.1002/app.36853]
|-valign="top"
|[5]
|Kroll, M., Langer, B., Schumacher, W., Grellmann, W.: The influence of carbon black batches on the fracture behavior of glass fiber reinforced PA6/PA66 blends. Journal of Applied Polymer Science 116 (2010) 610−618 DOI: [https://doi.org/10.1002/app.31611 https://doi.org/10.1002/app.31611]
|-valign="top"
|[6]
|Langer, B., Bierögel, C., Grellmann, W., Fiebig, J., Aumayr, G.: Material optimization of PP-short glass fibre compounds. In: Grellmann, W., [[Seidler,_Sabine|Seidler, S.]] (Eds.): Deformation and Fracture Behaviour of Polymers. Springer, Berlin, Heidelberg (2001) (ISBN 978-3540412472; see [[AMK-Library]] under A 7)
|-valign="top"
|[7]
|Maier, C., Calafut, T.: Polypropylene – The Definitive User’s Guide and Databook, William Andrew Publishing/Plastics Design Library (1998) (ISBN 978-0-0809-5041-9)
|-valign="top"
|[8]
|Marigo, A., Causin, V., Marega, C., Ferrari, P.: Crystallization of the gamma form in random propylene-ethylene copolymers. Polymer International 53 (2004) 2001−2008; DOI: [https://doi.org/10.1002/pi.1613 https://doi.org/10.1002/pi.1613]
|-valign="top"
|[9]
|Marigo, A., Marega, C., Causin, V., Ferrari, P.: Influence of thermal treatments, molecular weight, and molecular weight distribution on the crystallization of beta-isotactic polypropylene. Journal of Applied Polymer Science 91 (2004) 1008−1012; DOI: [https://doi.org/10.1002/app.13260 https://doi.org/10.1002/app.13260]
|-valign="top"
|[10]
|Raab, M., Kotek, J., Baldrian, J., Grellmann, W.: Übermolekulare Struktur und mechanische Eigenschaften von isotaktischem Polypropylen. In: Grellmann, W., Seidler, S. (Eds.): Deformation und Bruchverhalten von Kunststoffen. Springer Berlin Heidelberg (1998) (ISBN 3-540-63671-4; e-Book: ISBN 978-3-642-58766-5; see [[AMK-Library]] under A 6)
|-valign="top"
|[11]
|Monami, A., Langer, B., Sadlik, J., Kucera, J., Grellmann, W.: Fracture mechanics properties of polymorphic molypropylene. Procedia Materials Science 3 (2014) 276−281; DOI: [https://doi.org/10.1016/j.mspro.2014.06.048 https://doi.org/10.1016/j.mspro.2014.06.048]
|-valign="top"
|[12]
|Androsch, R., Monami, A., Kucera, J.: Effect of an alpha-phase nucleating agent on the crystallization kinetics of a propylene/ethylene random copolymer at largely different supercooling. Journal of Crystal Growth 408 (2014) 91−96; DOI: https://doi.org/10.1016/j.jcrysgro.2014.09.028
|-valign="top"
|[13]
|Hale, G. E., Ramsteiner, F.: A Testing protocol for conducting J-crack growth resistance curve on plastics. In: Moore, D. R., Pavan, A., Williams, J. G. (Eds.): Fracture Mechanics Testing Methods for Polymers Adhesives and Composites, Elsevier, Amsterdam, London, New York, Oxford, Paris, Shannon, Tokyo (2001) 123–157 (ISBN 0-0804-3689-7)
|}

[[Category:Fracture Mechanics]]

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Oluschinski:

Lexicon Polymer Testing & Diagnostics

2026-09-07T12:32:31Z

Oluschinski: Created page with "<big>Informations to Lexikon Polymer Testing & Diagnostics</big> <templatestyles src="Hauptseite/styles.css" />__NOTOC__ <div id="hauptseite"> <div id="spalten"> <div id="l" style="float:left; margin-right: 3em;"> <div id="PSM_Deckblatt>300px Cover page for the Lexicon Polymer Testing & Diagnostics Version 16.0</div> </div> <div id="r" style="float:left;"> '''Editors''' *Grellmann,_Wolfgang|Prof. Dr. rer...."

<big>Informations to Lexikon Polymer Testing & Diagnostics</big>

<templatestyles src="Hauptseite/styles.css" />__NOTOC__

<div id="hauptseite">

<div id="spalten">
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<div id="PSM_Deckblatt>[[File:Cover_Polymer-Wiki_(engl.)_Wiki16.jpg|300px]] Cover page for the Lexicon Polymer Testing & Diagnostics Version 16.0</div>
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<div id="r" style="float:left;">
'''Editors'''

*[[Grellmann,_Wolfgang|Prof. Dr. rer. nat. habil. Wolfgang Grellmann]] 
*[[Bierögel, Christian|Prof. Dr.-Ing. Christian Bierögel]] 
*[[Reincke, Katrin|Prof. Dr.-Ing. habil. Katrin Reincke]] 

'''Authors and coworkers'''

*Prof. Dr.-Ing. Ines Kotter 
*Dr.-Ing. Ralf Lach 
*Dipl.-Ing. Andreas Oluschinski 
*Dr.-Ing. Katja Oßwald 
*Dr.-Ing. Marcus Schoßig 
*Dipl.-Phys. Christian Sirch 
</div>
</div>

==Editorial board==

Please direct any enquiries regarding articles in this online encyclopaedia to the scientific editorial board.

*Lach, Ralf Dr.-Ing. (Vors.) [mailto:ralf.lach@psm-merseburg.de ralf.lach@psm-merseburg.de] 
*Oluschinski, Andreas Dipl.-Ing. [mailto:andreas.oluschinski@psm-merseburg.de andreas.oluschinski@psm-merseburg.de] 
*Sirch, Christian Dipl.-Phys. [mailto:christian.sirch@psm-merseburg.de christian.sirch@psm-merseburg.de] 

==Foreword==

The scientific basis for the Wiki Lexicon of Polymer Testing & Diagnostics is provided by the textbooks and specialist books published by the Merseburg School (see also [[AMK-Library]]) on polymer testing and diagnostics as well as on the technical fracture mechanics of plastics and composite materials with a polymer matrix. These include, among others:
 
'''Polymer Testing'''
 
[[Grellmann,_Wolfgang|Wolfgang Grellmann]] and [[Seidler,_Sabine|Sabine Seidler]] (Eds.) 
1st Edition 2007 
Carl Hanser, Munich, Vienna 
ISBN 978-1-56990-410-7 
ISBN 978-3-446-40900-2 
 
2nd Edition 2013 
Carl Hanser, Munich 
ISBN 978-1-56990-548-7 
 
3rd Edition 2022 
Carl Hanser, Munich 
ISBN 978-1-56990-806-8 
 
With the collaboration of 
[[Altstädt, Volker|Volker Altstädt]], Monika Bauer, [[Bierögel, Christian|Christian Bierögel]], Gert Busse, Klaus Friedrich, Henrick Höninger, Thomas Lüpke, Bernd Michel, [[Radusch, Hans-Joachim|Hans-Joachim Radusch]], Falko Ramsteiner, Andreas Schönhals, Jörg Trempler

Other reference books published by Springer-Verlag on the deformation and fracture behaviour of plastics are:
{|
|-valign="top"
|1.
|[[Grellmann,_Wolfgang|Grellmann, W.]], [[Seidler,_Sabine|Seidler, S.]] (Eds.): '''Deformation und Bruchverhalten von Kunststoffen'''. Springer, Berlin Heidelberg (1998), (ISBN 3-540-63671-4; e-Book: ISBN 978-3-642-58766-5; see [[AMK-Library]] under A 6)
|-valign="top"
|2.
|Grellmann, W., Seidler, S. (Eds.): '''Deformation and Fracture Behaviour of Polymers'''. Springer, Berlin Heidelberg (2001) (ISBN 978-3540412472; see [[AMK-Library]] under A 7)
|-valign="top"
|3.
|Grellmann, W., [[Reincke,_Katrin|Reincke, K.]]: '''Technical Material Diagnostics – Fracture Mechanics of Filled Elastomer Blends'''. In: Grellmann, W., Heinrich, G., Kaliske, M., Klüppel, M., Schneider, K., Vilgis, T. (Eds.): Fracture Mechanics and Statistical Mechanics of Reinforced Elastomeric Blends. Springer, Berlin Heidelberg (2013), (ISBN 978-3-642-37909-3; see [[AMK-Library]] under A 14)
|-valign="top"
|4.
|Grellmann, W., Seidler, S.: '''Mechanical and Thermomechanical Properties of Polymers'''. Landolt-Börnstein. Volume VIII/6A3, Springer, Berlin (2014), (ISBN 978-3-642-55165-9; see [[AMK-Library]] under A 16)
|-valign="top"
|5.
|Grellmann, W., Langer, B. (Eds.): '''Deformation and Fracture Behavior of Polymer Materials'''. Springer Series in Materials Science 247, Springer, Berlin Heidelberg (2017), (ISBN 978-3-319-41877-3; e-Book: ISBN 978-3-319-41879-7; see [[AMK-Library]] under A 19)
|}

'''Co-authors of the lexicon'''

[[File:FELMI_ZFE.PNG| 100px |thumb |[http://www.felmi-zfe.tugraz.at/ FELMI-ZFE]]]

1. Martin-Luther-University Halle-Wittenberg, Centre of Engineer Sciences, professorship Material Diagnostic/Material Testing (Chair '''[[Grellmann,_Wolfgang|Prof. em. Dr. rer. nat. habil. Wolfgang Grellmann]]''') and the University of Technology Graz, Institute of Electron-Microscopy and Nanoanalytics (FELMI) together with the Centre of Electron-Microscopy (ZFE) Graz (director '''Univ.-Prof. Dr. Gerald Kothleitner''', see: [http://www.felmi-zfe.at www.felmi-zfe.at]) with whom we have a long-standing collaboration in the field of [[Microscopic Structure|morphology]] and [[Micromechanics & Nanomechanics|micromechanics]] of plastics. 
The following terms were edited by '''Dr. Armin Zankel''', FELMI-ZFE Graz:
<ul>
<li>[[Energy Dispersive X-Ray Spectroscopy (EDX)]]</li>
<li>[[In-situ ultramicrotomy]]</li>
<li>[[Microtomy]]</li>
<li>[[Scanning Electron Microscopy]] (SEM)</li>
<li>[[Environmental-SEM (ESEM)]]</li></ul>

2. The Editors of the "Lexicon Polymer Testing & Diagnostics" have asked '''[[Michler,_Goerg_Hannes|Prof. em. Dr. rer. nat. habil. Goerg H. Michler]]''', Martin-Luther-Universiy Halle-Wittenberg, Institute for Physics, professurship "General Material Science", because of his professional competence in the field of morphology and micro-mechanics of polymers, to explain some terms. 
Following his retirement, Prof. Dr. Michler is now Honorary Chairman in [http://www.ipw-merseburg.de Institut für Polymerwerkstoffe e.V.], Associated institute at the University of applied Science Merseburg and also chairmen of the foundation [http://bethge-stiftung.de Heinz-Bethge-Stiftung] in Halle.

The following terms were edited from Prof. Dr. Michler:
* [[Craze-Types]]
* [[Electron Microscopy]]
* [[Polymers & Structure]]
* [[Micromechanics & Nanomechanics]]
* [[Transmission Electron Microscopy]]
* [[In-situ Ultramicrotomy]]
* [[Material Science & Plastics]]

3. The following terms were edited from '''[[Radusch,_Hans-Joachim|Prof. em. Dr.-Ing. habil. Hans-Joachim Radusch]]''', Martin-Luther-University Halle-Wittenberg, Cetre for Engineering Science, Chair "Kunststofftechnik":

* [[Elongational Viscosity]]
* [[Capillary Rheometer]]
* [[Surface Tension and Interfacial Tension]]
* [[Rheometry|Rheometry/Viscosimetry]]
* [[Pourability]]
* [[Rotational Rheometer]]
* [[Melt Mass-Flow Rate]]
* [[Melt Volume-Flow Rate]]
* [[Bulk Density]]
* [[Repose Angle]]
* [[Materials Science]]
* [[Materials Technology & Materials Science]]
* [[Materials Science & University Education in Merseburg-Halle|Materials Science & University Education in Merseburg/Halle]]

4. The following terms were edited from '''Prof. Dr.-Ing. habil. Michael Nase''', University of Applied Science, Hof, [https://www.ibp-hof.de/ Institute for Bio-Polymer Science], Professorship for Polymer Technology:
* [[Adhesive Energy Release Rate]]
* [[Peel Properties of Peel Systems]]
* [[Peeling Process]]
* [[Peel Behaviour – Modelling]]

5. The following terms were edited from '''Prof. Dr.-Ing. Stephan Marzi''', [https://www.thm.de/site/en/ Technical University Mittelhessen], [https://www.thm.de/me/ Department of Mechanical Engineering and Energy Technology], Gießen:
* [[Cohesive Zone Models]]
* [[ODCB or MC-DCB-Specimens]]
* [[Adhesive Joints – Determination of Characteristic Values]]

6. There is a long-standing scientific collaboration between Martin [https://www.uni-halle.de/?lang=en Luther University Halle-Wittenberg] and [https://www.tuwien.at/en/ Vienna University of Technology], which has resulted in numerous specialist books and publications in the fields of [[Polymer Testing|polymer testing]], [[Polymer Diagnostic|polymer diagnostics]] and technical [[Fracture Mechanics|fracture mechanics]] of [[Polymer|polymer]] and [[Composite Materials Testing|composite materials]]. 
The authors of this lexicon thank to Frau '''Prof. Dr. Vasiliki-Maria Archodoulaki''' and '''Dr. Lisa Schardt''', Vienna University of Technology, [https://tiss.tuwien.ac.at/adressbuch/adressbuch/orgeinheit/1673?locale=en Institute for Materials Science and Materials Technology], FG Structural Polymers, for the guest article:
* [[Microplastic & Nanoplastic]]
 
{{Kasten|
'''For literary citations in the lexicon, please use:''' 
Grellmann, W., Bierögel , C. (&dagger;), Reincke, K. (Eds.) Wiki "'''Lexicon Polymer Testing & Diagnostics'''" 2026, Version 16, http://wiki.polymerservice-merseburg.de
}}

Wolfgang Grellmann, Merseburg and Halle

Foreword last modified on January, the 27th, 2026

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|TITEL=Welcome to the PSM Wiki-lexicon "Polymer Testing & Diagnostics"
|INHALT=With this lexicon, we would like to explain important terms from the plastics sector to interested readers and our customers. Originating from a small glossary on the [https://www.psm-merseburg.de PSM homepage], a wiki lexicon has been created over the years that has more than 1,000 visitors a day. As with its big sister wikipedia, this wiki is also alive. New articles are regularly added and existing ones revised.
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|TITEL=Overview pages
|INHALT=
<ul>
<li>[[Fracture Mechanical Testing]]</li>
<li>[[Elastic Modulus]]</li>
<li>[[Instrumented Hardness Testing – Method & Material Parameters]]</li>
<li>[[Hardness]]</li>
<li>[[Polymer Testing]]</li>
<li>[[Polymer Diagnostic]]</li>
<li>[[Ultrasound Testing]]</li>
<li>[[Polymers & Structure]]</li>
<li>[[Specimen]]</li>
<li>[[Tensile Test]]</li>
<li>[[Surface Tension and Interfacial Tension]]</li>
<li>[[Laser Extensometry]]</li>
<li>[[J-Integral Evaluation Methods (Overview)]]</li>
<li>[[Content|Content A – Z]]</li>
</ul>
}}
{{Hauptseite/Box
|TITEL=Popular articles
|INHALT=
<ul>
<li>[[SHORE Hardness]]</li>
<li>[[Density]]</li>
<li>[[Processing Shrinkage]]</li>
<li>[[Multipurpose Test Specimen ]]</li>
<li>[[Poisson's Ratio]]</li>
<li>[[Compression Test]]</li>
<li>[[Electrical Strength]]</li>
<li>[[Tensile Strength]]</li>
<li>[[Surface Energy]]</li>
<li>[[Vicat Softening Temperature]]</li>
</ul>
|NAME=beliebt}}

{{Hauptseite/Box
|TITEL=New and revised articles
|INHALT=
<ul>
<li>[[Bio-Plastics]]</li>
<li>[[Bio-Plastics – Impact-Modified]]</li>
<li>[[Differential Scanning Calorimetry (DSC)]]</li>
<li>[[Fatigue Crack Propagation Elastomers]]</li>
<li>[[Glowing Hot-Wire Test]]</li>
<li>[[Instrumented Hardness Testing – Method & Material Parameters]]</li>
<li>[[Instrumented Scratch Testing]]</li>
<li>[[IRHD Hardness]]</li>
<li>[[Melt Mass-Flow Rate]]</li>
<li>[[Thermostability PVC]]</li>
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|TITEL=Categories
|INHALT=
<ul>
<li>[[:Category:Acoustic Test Methods_Ultrasonics|Acoustic Test Methods/Ultrasonics]]</li>
<li>[[:Category:Ageing|Ageing]]</li>
<li>[[:Category:Bend Test|Bend Test]]</li>
<li>[[:Category:Colour and Gloss|Colour and Gloss]]</li>
<li>[[:Category:Compression Test|Compression Test]]</li>
<li>[[:Category:Creep Behaviour Plastics|Creep Behaviour Plastics]]</li>
<li>[[:Category:Damage Analysis_Component Failure|Damage Analysis/Component Failure]]</li>
<li>[[:Category:Deformation engl|Deformation]]</li>
<li>[[:Category:Elastomers|Elastomers]]</li>
<li>[[:Category:Electrical and Dielectrical Testing|Electrical and Dielectrical Testing]]</li>
<li>[[:Category:Fatigue|Fatigue]]</li>
<li>[[:Category:Film Testing|Film Testing]]</li>
<li>[[:Category:Fire Behaviour|Fire Behaviour]]</li>
<li>[[:Category:Fracture Mechanics|Fracture Mechanics]]</li>
<li>[[:Category:Hardness|Hardness]]</li>
<li>[[:Category:Hybrid Methods|Hybrid Methods]]</li>
<li>[[:Category:Impact Tests|Impact Tests]]</li>
<li>[[:Category:Implant Testing|Implant Testing]]</li>
<li>[[:Category:Instrumented Impact Test|Instrumented Impact Test]]</li>
<li>[[:Category:Laser Extensometry|Laser Extensometry]]</li>
<li>[[:Category:Light|Light]]</li>
<li>[[:Category:Material Scientists Polymer Scientists|Material Scientists/Polymer Scientists]]</li>
<li>[[:Category:Materials Science_Materials Engineering|Materials Science/Materials Engineering]]</li>
<li>[[:Category:Measurement Testing Technology|Measurement Testing Technology]] (Measurement Data Aquisition)</li>
<li>[[:Category:Morphology and Micromechanics|Morphology and Micromechanics]]</li>
<li>[[:Category:Optical Field Measurement Methods|Optical Field Measurement Methods]]</li>
<li>[[:Category:Peel Test|Peel Test]]</li>
<li>[[:Category:Plastics|Plastics]]</li>
<li>[[:Category:Process-related Properties|Process-related Properties]]</li>
<li>[[:Category:Scientific Disciplines|Scientific Disciplines]]</li>
<li>[[:Category:Specimen|Specimen]]</li>
<li>[[:Category:Specimen Preparation|Specimen Preparation]]</li>
<li>[[:Category:Stiffness Compliance|Stiffness/Compliance]]</li>
<li>[[:Category:Stress Cracking Resistance|Stress Cracking Resistance]]</li>
<li>[[:Category:Surface Testing Technology|Surface Testing Technology]]</li>
<li>[[:Category:Tensile Test|Tensile Test]]</li>
<li>[[:Category:Thermoanalytical Methods|Thermoanalytical Methods]]</li>
<li>[[:Category:Velocity|Velocity]]</li>
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|INHALT=With this lexicon, we would like to explain important terms from the plastics sector to interested readers and our customers. Originating from a small glossary on the [https://www.psm-merseburg.de PSM homepage], a wiki lexicon has been created over the years that has more than 1,000 visitors a day. As with its big sister wikipedia, this wiki is also alive. New articles are regularly added and existing ones revised.
|NAME=Welcome}}

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|TITEL=Overview pages
|INHALT=
<ul>
<li>[[Fracture Mechanical Testing]]</li>
<li>[[Elastic Modulus]]</li>
<li>[[Instrumented Hardness Testing – Method & Material Parameters]]</li>
<li>[[Hardness]]</li>
<li>[[Polymer Testing]]</li>
<li>[[Polymer Diagnostic]]</li>
<li>[[Ultrasound Testing]]</li>
<li>[[Polymers & Structure]]</li>
<li>[[Specimen]]</li>
<li>[[Tensile Test]]</li>
<li>[[Surface Tension and Interfacial Tension]]</li>
<li>[[Laser Extensometry]]</li>
<li>[[J-Integral Evaluation Methods (Overview)]]</li>
<li>[[Content|Content A – Z]]</li>
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|TITEL=Popular articles
|INHALT=
<ul>
<li>[[SHORE Hardness]]</li>
<li>[[Density]]</li>
<li>[[Processing Shrinkage]]</li>
<li>[[Multipurpose Test Specimen ]]</li>
<li>[[Poisson's Ratio]]</li>
<li>[[Compression Test]]</li>
<li>[[Electrical Strength]]</li>
<li>[[Tensile Strength]]</li>
<li>[[Surface Energy]]</li>
<li>[[Vicat Softening Temperature]]</li>
</ul>
|NAME=beliebt}}

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|TITEL=New and revised articles
|INHALT=
<ul>
<li>[[Bio-Plastics]]</li>
<li>[[Bio-Plastics – Impact-Modified]]</li>
<li>[[Differential Scanning Calorimetry (DSC)]]</li>
<li>[[Fatigue Crack Propagation Elastomers]]</li>
<li>[[Glowing Hot-Wire Test]]</li>
<li>[[Instrumented Hardness Testing – Method & Material Parameters]]</li>
<li>[[Instrumented Scratch Testing]]</li>
<li>[[IRHD Hardness]]</li>
<li>[[Melt Mass-Flow Rate]]</li>
<li>[[Thermostability PVC]]</li>
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<ul>
<li>[[:Category:Acoustic Test Methods_Ultrasonics|Acoustic Test Methods/Ultrasonics]]</li>
<li>[[:Category:Ageing|Ageing]]</li>
<li>[[:Category:Bend Test|Bend Test]]</li>
<li>[[:Category:Colour and Gloss|Colour and Gloss]]</li>
<li>[[:Category:Compression Test|Compression Test]]</li>
<li>[[:Category:Creep Behaviour Plastics|Creep Behaviour Plastics]]</li>
<li>[[:Category:Damage Analysis_Component Failure|Damage Analysis/Component Failure]]</li>
<li>[[:Category:Deformation engl|Deformation]]</li>
<li>[[:Category:Elastomers|Elastomers]]</li>
<li>[[:Category:Electrical and Dielectrical Testing|Electrical and Dielectrical Testing]]</li>
<li>[[:Category:Fatigue|Fatigue]]</li>
<li>[[:Category:Film Testing|Film Testing]]</li>
<li>[[:Category:Fire Behaviour|Fire Behaviour]]</li>
<li>[[:Category:Fracture Mechanics|Fracture Mechanics]]</li>
<li>[[:Category:Hardness|Hardness]]</li>
<li>[[:Category:Hybrid Methods|Hybrid Methods]]</li>
<li>[[:Category:Impact Tests|Impact Tests]]</li>
<li>[[:Category:Implant Testing|Implant Testing]]</li>
<li>[[:Category:Instrumented Impact Test|Instrumented Impact Test]]</li>
<li>[[:Category:Laser Extensometry|Laser Extensometry]]</li>
<li>[[:Category:Light|Light]]</li>
<li>[[:Category:Material Scientists Polymer Scientists|Material Scientists/Polymer Scientists]]</li>
<li>[[:Category:Materials Science_Materials Engineering|Materials Science/Materials Engineering]]</li>
<li>[[:Category:Measurement Testing Technology|Measurement Testing Technology]] (Measurement Data Aquisition)</li>
<li>[[:Category:Morphology and Micromechanics|Morphology and Micromechanics]]</li>
<li>[[:Category:Optical Field Measurement Methods|Optical Field Measurement Methods]]</li>
<li>[[:Category:Peel Test|Peel Test]]</li>
<li>[[:Category:Plastics|Plastics]]</li>
<li>[[:Category:Process-related Properties|Process-related Properties]]</li>
<li>[[:Category:Scientific Disciplines|Scientific Disciplines]]</li>
<li>[[:Category:Specimen|Specimen]]</li>
<li>[[:Category:Specimen Preparation|Specimen Preparation]]</li>
<li>[[:Category:Stiffness Compliance|Stiffness/Compliance]]</li>
<li>[[:Category:Stress Cracking Resistance|Stress Cracking Resistance]]</li>
<li>[[:Category:Surface Testing Technology|Surface Testing Technology]]</li>
<li>[[:Category:Tensile Test|Tensile Test]]</li>
<li>[[:Category:Thermoanalytical Methods|Thermoanalytical Methods]]</li>
<li>[[:Category:Velocity|Velocity]]</li>
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[[file:Deckblatt_Kunststoffpruefung.jpg]] About the [Lexicon Polymer Testing & Diagnostics]]
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AMK-Library

2026-09-07T12:28:31Z

Oluschinski: Created page with "You can find a current list of all works of the AMK-Library here: *[http://amk-merseburg.de/buechersammlung/ www.amk-merseburg.de]"

You can find a current list of all works of the AMK-Library here:

*[http://amk-merseburg.de/buechersammlung/ www.amk-merseburg.de]

File:S E Pruefkoepfe-3.JPG

2026-09-07T12:27:42Z

Oluschinski:

File:Griffith.jpg

2026-09-07T12:25:17Z

Oluschinski:

2026-09-07T12:17:49Z

Oluschinski:

Vickers Hardness

2026-09-07T12:17:29Z

Oluschinski: Created page with "{{Language_sel|LANG=ger|ARTIKEL=Vickers-Härte}} {{PSM_Infobox}} Vickers hardness __FORCETOC__ ==General information== The Vickers hardness testing method (named after the English company Vickers) was developed in 1925 by Smith and Sandland. The decisive factor was that the applicability of Brinell hardness was limited due to the flattening of the steel ball, and carbide balls were not yet available at that time...."

{{Language_sel|LANG=ger|ARTIKEL=Vickers-Härte}}
{{PSM_Infobox}}
Vickers hardness
__FORCETOC__

==General information==

The Vickers hardness testing method (named after the English company Vickers) was developed in 1925 by Smith and Sandland. The decisive factor was that the applicability of Brinell hardness was limited due to the flattening of the steel ball, and carbide balls were not yet available at that time.

==Measurement principle of Vickers hardness==

The Vickers method is very similar to the Brinell method. Instead of a ball, a regular, four-sided diamond pyramid with a square base and an angle of 136° between the opposite areas is used as the [[Indenter|indenter]]. The indenter is pressed vertically into the test specimen or sample with a test load ''F'', and the impression is normally measured under a light microscope in the manner illustrated in the image after the load is removed:

[[File:Vickers Hardness.jpg]]
{|
|- valign="top"
|width="50px"|'''Fig.''':
|width="600px" |Schematic illustration of Vickers [[Hardness|hardness]] testing with measurement technology (a), indentation creation (b), and indentation measurement (c)
|}

The test load must be adapted to the respective geometric and morphological conditions; as a rule, tests are performed with loads ≤ 5 N. Normally, the test load ''F'' in the Vickers hardness test is selected so that the indentation diagonal ''d'' is relatively large compared to the structural components (internal averaging) and can thus be measured more [[Measuring Accuracy|accurately]] (lower relative error). However, the [[Hardness|hardness]] of individual structural components can also be measured specifically, in which case the geometric conditions must be selected in exactly the opposite way.

==Definition of Vickers hardness==

The lengths of the two indentation diagonals are determined as the [[Measured Variable|measured variables]]. From this, the average indentation diagonal ''d'' is calculated, which is used to calculate the Vickers hardness HV.

{|
|-
|width="20px"|
|width="500px" | <math>HV\,=\,\frac{F}{A}\,=\,\frac{0{.}1891 \; F}{d^2}</math>
|}

with
{|
|-
|HV
|width="15px" |
|Vickers hardness in N mm-2
|-
|''F''
|
|test load in N
|-
|''A''
|
|Indentation surface in mm2
|-
|''d''
|
|Average value of indentation diagonal in mm
|}

''Comment:''

''In the hardness testing of [[Plastics|plastics]], the physically exact unit of measurement N mm-2 is always specified for the hardness value. When testing the hardness of metallic materials, the test force F is multiplied by 0.102 (≈1/9.80665 = 1/gn) (gn – acceleration due to gravity). The resulting value has the dimension kp. However, since the kp was removed from the hardness designation, this unit is no longer specified; only the hardness value without dimension is given. The kp can still be found as a specification for the test force levels, especially on older hardness testing machines.''

When performing the Vickers test, the resulting indentation is normally measured after unloading, but there are also ways to determine it under load. In this case, the test specimen surface and thus the indentation diagonal are observed through the diamond [[Indenter|indenter]], which allows, for example, real-time conclusions to be drawn about [[Creep Plastics|creep behaviour]].

While the Vickers method is standardized for metallic materials and therefore test load recommendations exist for the micro, small load, and macro ranges, the Vickers method is not standardized for [[Plastics|plastics]].

==Instrumented hardness testing with Vickers indenter==

In [[Hardness#Instrumented hardness testing|instrumented hardness testing]] with Vickers indenters, the entire indentation process is recorded during loading and load–indentation depth diagrams are recorded. Due to the pyramid geometry, the indentation depth ''h'' is related to the indentation diagonal ''d'' by the relationship ''h'' = ''d''/7.0006.

In addition to the hardness value, [[Hardness#Instrumented hardness testing|instrumented hardness testing]] can be used to determine other mechanical [[Material Parameter|material parameters]] such as the modulus of elasticity ([[Indentation Modulus|indentation modulus]]), work hardening exponents, and [[Viscoelastic Material Behaviour|viscoelastic properties]].

==See also==

* [[Conventional Hardness Testing|Conventional hardness testing]]
* [[Ball Indentation Hardness|Ball indentation hardness]]
* [[Scratch Hardness|Scratch hardness]]
* [[TABOR Relationship|TABOR relationship]]
* [[Instrumented Scratch Testing|Instrumented scratch testing]]

==References==

* [[Blumenauer, Horst]] (Ed.): Werkstoffprüfung. Deutscher Verlag für Grundstoffindustrie, Leipzig Stuttgart (1994) 6th Edition, (ISBN 978-3-342-00547-6; see [[AMK-Library]] under M 3)
* [[Grellmann,_Wolfgang|Grellmann, W.]], [[Seidler,_Sabine|Seidler, S.]] (Eds.): Kunststoffprüfung. Carl Hanser, Munich (2022) 3rd Edition, p. 180 (ISBN 978-1-56990-806-8; e-Book ISBN 978-1-56990-807-5; see [[AMK-Library]] under A 22)

[[Category:Hardness]]

Vicat Softening Temperature

2026-09-07T12:17:08Z

Velocity

2026-09-07T12:14:13Z

Ultrasound Testing

2026-09-07T10:43:46Z

Oluschinski:

{{Language_sel|LANG=ger|ARTIKEL=Ultraschallprüfung}}
{{PSM_Infobox}}
Ultrasound testing
__FORCETOC__

==History of ultrasound==

Flaw detection based on ultrasound is one of the oldest [[Non-destructive Testing (NDT) | non-destructive testing methods]] alongside X-ray gross structure analysis. Following the discovery of the [[Piezoelectric Force Transducer|piezoelectric effect]] (1880–1881) by the Curie brothers for measuring and generating non-stationary pressures and vibrations, the beginnings of the technical utilisation of ultrasound can be dated to around 1940. It was recognised that ultrasound interacts with the workpiece to be tested and reacts with a change in intensity and transit time. In 1942, the technical foundations were laid for time-of-flight measurement with separate transmitter and receiver sensors in through-transmission mode (Trostzange) and later for pulse-echo technology. In the years 1949–1950, Krautkrämer, Hürth, developed the first analogue ultrasonic testing device for non-destructive fault detection using [[Pulse-Echo Ultrasonic Technique | pulse-echo ultrasonic technique]]. In 1973, Karl Deutsch released the first device with a digital display and in 1982 the Echograph with an integrated microprocessor.

Following the development of angle beam sensors (approx. 1952) and [[Ultrasonic Transmitter(S)-Receiver(E) Sensors|transmitter-receiver sensors]] (approx. 1957), welded joints and thin components could be analysed for specific manufacturing or processing-related defects. The development of [[Ultrasonic Immersion Bath Technique | ultrasonic immersion bath technology]] using imaging ultrasound can be dated to around 1970 and squirter technology and [[Air-Ultrasound | air-ultrasound]] to around 1980 [1, 2]. More recent developments in digital testing technology, phased array technology, the TOFD testing and evaluation method (Time of Flight Diffraction Technique) or guided waves prove that the physical limits of ultrasonic testing technology are far from exhausted.

==Ultrasonic testing technology==

Ultrasonic testing is an active acoustic testing method in which ultrasonic waves (longitudinal or transverse waves) are transmitted into a test piece using one or more sensors (sensor field) to detect internal defects (imperfections) or determine geometric dimensions (wall thickness). Using a second sensor (receiver in through-transmission technology) or after switching the transmitter to receive ([[Pulse-Echo Ultrasonic Technique|pulse-echo technology]]), the sound waves, which have changed in transit time, frequency and intensity, are received and further processed for display purposes, utilising the inverse piezoelectric effect.

Ultrasonic testing, known in medicine as sonography, is based on the use of ultrasonic waves with a frequency > 20 kHz, whereby technical applications use the frequency range from approx. 100 kHz to 100 MHz. As the sound waves propagate in different media at different ultrasound velocities (see: [[Ultrasonic Runtime Measurement | ultrasonic runtime measurement]]) and are reflected, shadowed, refracted or scattered and weakened at media interfaces with different sound impedance (air, water, metal), these physical effects can be used to detect defects or imperfections (blowholes, inclusions), whereby generally only defects that are greater than half the wavelength (''λ''/2) are recognisable. These methods can be used to determine the type and size of defects based on known target values and the depth of the discontinuity in the test piece can be determined using time-of-flight measurement. However, due to different acoustic impedances at external interfaces, coupling agents (oil, water) are usually required to introduce the ultrasound into the test piece, which minimise the [[Ultrasonic Waves Reflection | reflection]] of the ultrasound at the [[Surface|surface]] [3−6] or improve the [[Transmission Sound Waves|transmission]] of sound waves into the solid.

==Ultrasonic sensors==

Depending on the application and type of wave, different [[Ultrasonic Sensors|ultrasonic sensors]] are used in practice:

* [[Ultrasonic Standard Sensors|Standard sensors]]
* [[Ultrasonic Angle Beam Sensors|Angle sensors]]
* [[Ultrasonic Transmitter(S)-Receiver(E) Sensor | Transmitter (S)-receiver (E) sensors]]
* [[Ultrasonic Composite Sensors|Composite sensors]]
* [[Ultrasonic Shock Wave Sensors|Shock wave sensors]]
* [[Ultrasonic Immersion Bath Sensors|Immersion bath sensors]]
* [[Ultrasonic Phased Array Sensors|Phased array sensors]]

==Imaging visualisation==

The simplest display method in ultrasonic testing is the [[A-Scan Technique|A-scan]], which represents the square of the [[HF-Scan|HF-scan]]. Scanning imaging test methods ([[Ultrasonic Immersion Bath Technique | immersion bath]], phased array technology or air ultrasound) can be used to generate the [[B-Scan Technique|B-]], [[C-Scan Technique|C-]] and [[D-Scan Technique|D-scan]] or the [[F-Scan Technique|F-scan]] with significantly improved informative value through frequency-related evaluation. Special inspection and evaluation techniques such as [[Ultrasonic Time-of-Flight Diffraction (TOFD) Technique|TOFD]] (time-of-flight diffraction technique) or SAFT (Synthetic Aperture Focusing Technique) are also available.

In principle, ultrasonic testing is standardised in ISO 16810 and the terminology used is standardised in DIN EN 1330-4, whereby special standards apply for the various applications on [[Ultrasonic Weld Inspection|welded joints]], forgings or [[Ultrasonic Wall Thickness Measurement | wall thickness measurement]], although mostly only for metallic materials [7, 8]. There are currently no binding standards for ultrasonic testing of [[Plastics | plastics]].

==Qualification of ultrasonic inspectors==

A personnel certification (DPZ certificate), usually from the [https://en.wikipedia.org/wiki/German_Research_Foundation German Society for Non-Destructive Testing – DGZfP], is required to carry out ultrasonic testing and is valid for 5 years for a specific testing method [9]. There are 3 qualification levels 1 to 3 (Level) for ultrasonic testing UT, which are also adapted to the various areas of application (e.g. aerospace industry, welding technology or cast part and pipe production).

==See also==

* [[Non-destructive Polymer Testing | Non-destructive polymer testing]]
* [[Acoustic Properties | Acoustic properties]]
* [[Ultrasound – Elastic Parameters | Ultrasound – Elastic parameters]]
* [[Air-Ultrasound | Air-ultrasound]]
* [[Ultrasonic Runtime Measurement | Ultrasound runtime measurement]]

==References==

{|
|-valign="top"
|[1]
|Husarek, V., Castel, J. G.: [https://www.ndt.net/article/dgzfp01/papers/v03/v03.htm Beitrag zur Geschichte der Ultraschallprüfung in Deutschland und Frankreich]. DGZfP-Jahrestagung „Zerstörungsfreie Werkstoffprüfung“ 2001, Sofranell, Frankreich, Proceedings 75-CD
|-valign="top"
|[2]
|Guicking, D.: Erwin Meyer – Ein bedeutender deutscher Akustiker – Biographische Notizen. Universitätsdrucke, Universitätsverlag, Göttingen (2012), ([http://www.guicking.de/dieter/Erwin-Meyer.pdf http://www.guicking.de/dieter/Erwin-Meyer.pdf]) (accessed on 26/05/2025)
|-valign="top"
|[3]
|Krautkrämer, J., Krautkrämer H.: Werkstoffprüfung mit Ultraschall. Springer, Berlin (1986), (ISBN 978-3-662-10909-0)
|-valign="top"
|[4]
|Deutsch, V., Platte, M., Vogt, M.: Ultraschallprüfung – Grundlagen und industrielle Anwendungen. Springer, Berlin (1997), (ISBN 3-540-62072-9; see [[AMK-Library]] under M 45)
|-valign="top"
|[5]
|Matthies, K. u. a.: Dickenmessung mit Ultraschall. DVS-Verlag GmbH, 2nd Edition, Berlin (1998), (ISBN 3-87155-940-7; see [[AMK-Library]] under M 44)
|-valign="top"
|[6]
|Schiebold, K.: Zerstörungsfreie Werkstoffprüfung – Ultraschallprüfung. Springer, Berlin (2014), (ISBN 978-3-662-44699-7)
|-valign="top"
|[7]
|ISO 16810 (2024-10): Non-destructive Testing – Ultrasonic Testing – General Principles
|-valign="top"
|[8]
|DIN EN 1330-4 (2010-05): Non-destructive Testing – Terminology – Part 4: Terms Used in Ultrasonic Testing (withdrawn; replaced by ISO 5577 (2025-09))
|-valign="top"
|[9]
|ISO 9712 (2021-12): Non-destructive Testing – Qualification and Certification of NDT Personnel
|-valign="top"
|}

[[Category:Acoustic Test Methods_Ultrasonics]]
[[Category:Velocity]]

File:US gefuehrte Wellen-2.jpg

2026-09-07T10:43:20Z

Oluschinski:

File:US gefuehrte Wellen-1.jpg

2026-09-07T10:43:11Z

Oluschinski:

Ultrasound-guided Waves

2026-09-07T10:42:42Z

Oluschinski: Created page with "{{Language_sel|LANG=ger|ARTIKEL=Ultraschall-Geführte-Wellen}} {{PSM_Infobox}} Ultrasound guided waves __FORCETOC__ ==Definition of guided waves== By definition, ‘guided waves’ are types of waves that propagate in the main axis direction of a comparatively thin medium, i.e. they are conducted or guided through the medium. The distance or thickness ''d'' of the confining surface layers in the normal direction is..."

{{Language_sel|LANG=ger|ARTIKEL=Ultraschall-Geführte-Wellen}}
{{PSM_Infobox}}
Ultrasound guided waves
__FORCETOC__

==Definition of guided waves==

By definition, ‘guided waves’ are types of waves that propagate in the main axis direction of a comparatively thin medium, i.e. they are conducted or guided through the medium. The distance or thickness ''d'' of the confining surface layers in the normal direction is approximately in the order of magnitude of the wavelength ''λ'', i.e. ''d'' ≈ ''λ''. The term ‘guided waves’ is therefore justified by the ‘guidance’ of the waves through the geometry of the tested [[Plastic Component|component]], although [https://en.wikipedia.org/wiki/Lamb_waves Lamb] or plate waves are generally a vibration-related property of thin plates or membranes, as is the hat wave.

==Types of waves and their propagation==

The plate waves or guided waves, which propagate differently from Rayleigh waves (surface waves, see '''Fig. 1a'''), Stoneley waves and Love waves ('''Fig. 1b''') in the presence of [[Phase Boundary Surface|interface surfaces]], are divided into symmetric and asymmetric plate or Lamb waves ('''Fig. 2''') and represent their vibration modes. Stoneley and Love waves, which are also known from seismology [1], have so far been of little significance in [[Non-destructive Testing (NDT)|non-destructive testing (NDT)]], but are already being used for special applications in [[Ultrasound Testing|ultrasound testing]] [2−4]. Surface waves (Fig. 1a) are very important for [[Sound Emission Testing|sound emission testing]] (SEP) and acousto-ultrasonics testing, as these waves are only slightly attenuated in their direction of propagation and can therefore be received over long distances, whereby special AE probes are used [5, 6]. The symmetric plate wave ('''Fig. 2a''') is also referred to as the S-type and the asymmetric wave as the A-type ('''Fig. 2b''') with different vibration modes (index 1, 2, 3) if the wavelength becomes very small. With such geometric wave types, the propagation velocity generally depends on the wavelength and leads to [[Dispersion|dispersion]] phenomena in the [[Material & Werkstoff|material]].

[[File:US_gefuehrte_Wellen-1.jpg]]
{|
|- valign="top"
|width="50px"|'''Fig. 1''':
|width="600px"|Direction of propagation (AR) and direction of vibration (SR) of (a) Rayleigh waves and (b) Love waves
|}

[[File:US_gefuehrte_Wellen-2.jpg]]
{|
|- valign="top"
|width="50px"|'''Fig. 2''':
|width="600px"|Examples of guided waves: (a) symmetric plate wave, (b) asymmetric plate wave (Lamb waves) with the direction of propagation (AR) and direction of vibration (SR)
|}

Plate waves with limited geometries, as shown in '''Figure 2a''', are also referred to as expansion or compression waves, whereby it can be seen that the neutral fibre of the plate does not change its geometric position (pure longitudinal vibration), in contrast to the asymmetrical wave in '''Figure 2b''', where the neutral fibre performs a transverse vibration. It is typical for Lamb waves that also harmonics can occur, although their amplitude decreases significantly with increasing order.

==Requirements for component testing==

The guided surface waves do not emerge from the [[Material & Werkstoff|material]] but remain ‘attached’ to the geometry, similar to light waves in glass fibres. This means that possible geometric changes, such as component curvatures or edges, do not pose an obstacle for these waves and (due to ''d'' ≈ ''λ'') no [[Ultrasonic Waves Reflection|reflection]] of sound waves occurs at them. As a result, the loss of sound energy into the adjacent media is considerably lower than with established methods of [[Ultrasound Testing|ultrasound testing]], such as the [[Pulse-Echo Ultrasonic Technique|pulse-echo method]]. The guided waves therefore propagate almost undamped in the tested medium and can therefore be transmitted over relatively long distances to perform tests on [[Plastic Component|components]] that are inaccessible in places, such as pipe penetrations under roads or buildings [7]. Guided waves are actively excited in the component to be tested by means of a suitable transmitter and received by the identical receiver (echo mode) or an additional ultrasonic probe ([[Ultrasonic Transmission Technique|transmission mode]]).

When propagating guided waves, however, it should be noted that different wave modes can be excited depending on the excitation frequency and the component thickness, and [[Dispersion|dispersions]] can occur [8], which can sometimes make it considerably more difficult to interpret structural damage that has occurred.

==Application examples for guided waves==

However, guided waves have a wide range of applications and are particularly useful when sections of large [[Component Testing|components]], such as pipes or tanks, are difficult to access. Current technical literature cites the following areas of application [9−13]:

* Inspection of plates,
* Pipe inspection,
* Inspection of [[Adhesive Joints – Determination of Characteristic Values|adhesive joints]],
* Airfoil inspection,
* Structural monitoring for early damage detection (permanent),
* Inspection of wind turbines (rotor blades),
* Container and tank inspection.

==See also==

* [[Ultrasonic Direct Coupling|Ultrasonic direct coupling]]
* [[Ultrasound – Elastic Parameters|Ultrasound – Elastic parameters]]
* [[Ultrasonic Modulation|Ultrasonic modulation]]
* [[Ultrasonic Transmitter(S)-Receiver(E) Sensors|Ultrasonic transmitter(S)-receiver(E) sensors]]
* [[Ultrasonic Wall Thickness Measurement|Ultrasonic wall thickness measurement]]

==References==

{|
|-valign="top"
|[1]
|Clauser, C.: Einführung in die Geophysik. Springer, Berlin Heidelberg, 2nd Edition (2016), (ISBN 978-3-662-46883-8)
|-valign="top"
|[2]
|Malischewsky, P. G., Schnapp, J.-D.: Oberflächenwellen und Materialprüfung aus seismologischer Sicht. DGZfP-Dach Jahrestagung, Salzburg (2004)
|-valign="top"
|[3]
|Wendrich, A.: Zerstörungsfreie Ortung von Anomalien in historischem Mauerwerk mit Radar und Ultraschall – Möglichkeiten und Grenzen. ([https://e-pub.uni-weimar.de/opus4/frontdoor/index/index/start/0/rows/10/sortfield/score/sortorder/desc/searchtype/simple/query/Zerst%C3%B6rungsfreie+Ortung+von+Anomalien+in+historischem+Mauerwerk+mit+Radar+und+Ultraschall+%E2%80%93+M%C3%B6glichkeiten+und+Grenzen/docId/1397 Dissertation]), Bauhaus-Universität Weimar (2008)
|-valign="top"
|[4]
|Jüngert, A.: Untersuchung von GFK-Bauteilen mit akustischen Verfahren am Beispiel der Rotorblätter von Windenergieanlagen. ([https://www.deutsche-digitale-bibliothek.de/item/OP6NMQB4ID6D36DV2L6L32K4JFFSD7IE?isThumbnailFiltered=true&query=Untersuchung+von+GFK-Bauteilen+mit+akustischen+Verfahren+am+Beispiel+der+Rotorbl%C3%A4tter+von+Windenergieanlagen&rows=20&offset=0&viewType=list&firstHit=OP6NMQB4ID6D36DV2L6L32K4JFFSD7IE&lastHit=lasthit&hitNumber=1 Dissertation]), Universität Stuttgart (2010) (access on November 30, 2025)
|-valign="top"
|[5]
|Meyer, E., Neumann, E.-G.: Physikalische und technische Akustik. Springer Verlag, Berlin, 2nd Edition, (2013), (ISBN 978-3-322-91086-8)
|-valign="top"
|[6]
|Grosse, C. U., Ohtsu, M. (Eds.): Acoustic Emission Testing. Springer Verlag, Berlin (2008), (ISBN 978-3-540-69895-1)
|-valign="top"
|[7]
|Prager, J., Gravenkamp, H., Rahman, M.-U., Köppe, E.: Einsatz geführter Wellen für die Ultraschallprüfung. tm − Technisches Messen Plattform für Methoden, Systeme und Anwendungen der Messtechnik. 79 (2012) 5, pp. 251–261, DOI: https://www.degruyter.com/document/doi/10.1524/teme.2012.0168/html
|-valign="top"
|[8]
|Schmidt, D.: Modenselektive Übertragung von Lambwellen in Faserverbundstrukturen. [https://www.gbv.de/dms/bs/toc/795057849.pdf Dissertation], Technische Universität Braunschweig (2014) (access on November 30, 2025)
|-valign="top"
|[9]
|Prager, J., Köppe, E. Bartholmai, M.: Früherkennung von Strukturschäden mittels geführter Lamb-Wellen. GMA/ITG-Fachtagung Sensoren und Messsysteme. Proceedings (2012) pp. 531–540
|-valign="top"
|[10]
|Schubert, L., Klesse,T., Weihnacht, B., Schulze, E., Lieske, U., Frankenstein, B.: Aktuelle Entwicklungsarbeiten zu aktiv angeregten geführten Wellen (Acousto-Ultrasonics) für SHM-Anwendungen. 20. Kolloquium Schallemission, DGZfP (2015) https://www.ndt.net/search/docs.php3?id=20941
|-valign="top"
|[11]
|Rau, E., Bamberg, J., Berwig, P.: Ultraschallprüfung an Turbinenschaufeln mittels Oberflächenwellen. DGZfP-Seminar FA Ultraschallprüfung (2015), Lecture No. 8; https://www.ndt.net/article/dgzfp-ut-2015/papers/8.pdf
|-valign="top"
|[12]
|Prager, J., Brackrock, D., Dohse, E., Gaal, M., Homann, T., Grezeszkowski, M.: Anwendung geführter Ultraschallwellen für die Prüfung von Klebeverbindungen. DGZfP-Dach Jahrestagung, Potsdam (2014)
|-valign="top"
|[13]
|Schiebold, K.: Zerstörungsfreie Werkstoffprüfung – Ultraschallprüfung. Springer, Berlin (2014), (ISBN 978-3-662-44699-7)
|}

==Weblink==

* Wikipedia – The free encyclopedia: https://en.wikipedia.org/wiki/Lamb_waves (access on February 25, 2026)

[[Category:Acoustic Test Methods_Ultrasonics]]

Ultrasound – Elastic Parameters

2026-09-07T10:42:24Z

Oluschinski:

{{Language_sel|LANG=ger|ARTIKEL=Ultraschall-Elastische Kennwerte}}
{{PSM_Infobox}}
Ultrasound – Elastic parameters

Determination of the elastic parameters with ultrasound
__FORCETOC__

==General==

The determination of elastic [[Material Value | material values]] by means of ultrasonic measurement technology is a measurement method of non-destructive plastics testing which, under certain conditions, provides more accurate results compared to the tensile test with longitudinal and transverse extensometers than is possible in the material testing machine with mechanical or optical extensometers. In addition, this method is very economical, as it is not only non-destructive, but can also be carried out relatively quickly.

The calculation equations of the modulus of elasticity, the shear modulus, the compression modulus and the [[Poisson's Ratio | Poisson's ratio]] are derived from the theory of elasticity, which contain the mass density and the longitudinal and transverse sound velocities of the tested material [1].

These equations apply exactly to materials with linear-elastic behaviour such as metals and ceramics and can therefore only be used approximately for heterogeneous materials. For plastics, it should be noted that due to their viscoelasticity – and also the heterogeneity of the semi-crystalline polymers – a high sound attenuation is generally to be expected, and stronger scattering occurs in the measurement series [2, 3]. That's why lower measuring frequencies are to be used for these materials, whereby the inhomogeneities should be several times smaller than the wavelength, so that the calculation equations, as listed below, are still valid.

==Specimen==

In order to carry out the measurements, a special geometry of test [[Specimen | specimens]] is necessary, which allows an accurate determination of the longitudinal and transverse ultrasonic velocities. The following figure ('''Fig. 1''') shows a possible geometry.

[[file:US_Elastische_Kennwerte-1.jpg]]
{|
|- valign="top"
|width="50px"|'''Fig. 1''':
|width="600px"|Prismatic test specimen with bevelled edge
|}

The geometry of a cuboid allows the measurement of both sound velocities, with the bevel adapted to the direction of the sound beam incident from the angle probe (the main axis of the sound field forming) (cf. '''Fig. 2b'''). This adjustment is made so that the transverse wave (see also: Refraction of sound waves) hits the bevel perpendicularly.

==Measurement of sound velocities==

For the measurement of the longitudinal sound velocity ''c''L, a normal probe (also called perpendicular transducer) is used according to the [[Pulse-Echo Ultrasonic Technique | pulse-echo method]]. It is coupled to the test specimen (according to '''Fig. 2a''') in such a way that the main axis (= acoustic axis) of the developing sound field meets the two opposite plane-parallel surfaces of the test specimen perpendicularly. This means that the acoustic axes of the sound fields of the incoming sound beam and the sound beam returning from the wall are the same, and the speed of sound can be calculated using the formula

{|
|-
|width="20px"|
|width="500px" | <math> c_{L} = \frac{2 d}{t_{S}}</math>.
|(1)
|}

Within the time ''t''S (sound travel time), the sound wave travels through twice the thickness ''d''.

[[file:US_-_Elastic_Parameters_2.jpg|700px]]
{|
|- valign="top"
|width="50px"|'''Fig. 2''':
|width="600px"|Prismatic specimen with bevelled edge and coupling of a normal ('''a''') and an angle probe ('''b''')
|}

To measure the transverse sound velocity ''c''T, the angle probe is aligned so that the sound beam, i.e. the main axis of the sound field, is perpendicular to the bevelled surface ('''Fig. 2b'''). The longitudinal sound velocity is determined completely analogously according to formula (1).

==Determining the elastic material parameters==

The material's moduli ([[Elasticity|elasticity]] (''E''), shear (''G''), compression (''K'') modulus) as well as the [[Poisson's Ratio|Poisson's ratio]] ''μ'' result from the relationships between the linear-elastic material parameters and the density ''ρ'' as well as the speed of sound. They have the following form:

{|
|-
|width="20px"|
|width="500px" | <math>E = \varrho \frac{3 \ c_{L}^{2} c_{T}^{2} - 4 c_{T}^{4}}{\ c_{L}^{2}-\ c_{T}^{2}}</math>
|(2)
|}

{|
|-
|width="20px"|
|width="500px" | <math>G = \varrho\ c_{T}^{2}</math>
|(3)
|}

{|
|-
|width="20px"|
|width="500px" | <math>K = \frac{G\ E}{9G-3E^{'}}</math>
|(4)
|}

{|
|-
|width="20px"|
|width="500px" | <math>\mu = \frac{1}{2} \frac{c_{L}^{2} -2 c_{T}^{2}} {\ c_{L}^{2}-\ c_{T}^{2}}</math>
|(5)
|}

Strictly speaking, these relations apply to isotropic solids. Thus, these equations are exactly valid for homogeneous (non-porous) ceramics [4]. However, they can also be used as a good approximation to determine the elastic properties of heterogeneous materials. This is always the case when the inhomogeneities (see: [[Failure Analysis – Basics|damage analysis]] and [[Component Failure|component failure]]) in the materials are small compared to the wavelength at which ultrasonic waves propagate in the material.

==Comments on the accuracy of the procedure==

The structure of the sound field is different for normal and angle beam probes. The normal probe has an axially symmetrical sound field that tapers off as the nominal frequency of the probe increases. This makes it possible to measure the speed of sound very accurately if both the surface on which the transducer is placed and the sounded boundary surface (see: [[Phase Boundary Surface | phase boundary surface]]) are normal to the axis of the sound field. Here, if the sound attenuation is not too high, the multiple echo method is recommended (see: [[Ultrasonic Wall Thickness Measurement | ultrasonic wall thickness measurement]]).

The inaccuracies are more likely to occur with the angle probe, whose sound field has a larger divergence angle (see: [[Ultrasonic Standard Sensors| ultrasonic standard sensors]]). Thus, according to the distance law <math>I = I_0 \cdot r^{-2}</math>, the reflected amplitude of the wave emitted by the angle probe is significantly lower than that of the normal probe. Here ''I''0 represents the intensity of the wave emitted by the probe, I that of the received wave and r the double distance between probe and reflecting surface. This sound attenuation is therefore greater with the angle probe. In addition, the nominal frequency of angle probes is limited to a maximum of 5 MHz [5], which means that the same accuracy cannot be achieved as with a normal probe (≥ 10 MHz). Therefore, the angle probe should first be calibrated to measure the transverse sound velocity.

==See also==

* [[Ultrasonic Direct Coupling | Ultrasonic direct coupling]]
* [[Pulse-Echo Ultrasonic Technique | Pulse-echo ultrasonic technique]]
* [[Ultrasonic Weld Inspection | Ultrasonic weld inspection]]
* [[Ultrasonic Runtime Measurement | Ultrasonic runtime measurement]]
* [[Ultrasonic Immersion Bath Technique | Ultrasonic immersion bath technique]]

==References==

{|
|-valign="top"
|[1]
|Landau, L. D., Lifschitz, E. M.: Lehrbuch der theoretischen Physik – Elastizitätstheorie Bd. 7, Akademieverlag Berlin (2009)
|-valign="top"
|[2]
|Krautkrämer, J., Krautkrämer, H.: Die Schwächung von Ultraschallwellen in festen Stoffen. In: Krautkrämer, J., Krautkrämer, H. (Hrsg.): Werkstoffprüfung mit Ultraschall. Springer Verlag Berlin, Heidelberg (1990) (ISBN 978-3-662-1082-2)
|-valign="top"
|[3]
|[[Grellmann, Wolfgang|Grellmann, W.]], [[Bierögel, Christian|Bierögel, C.]], [[Reincke, Katrin|Reincke, K.]] (Eds.): Wiki „Lexikon Kunststoffprüfung und Diagnostik“ 2025, Version 15, https://wiki.polymerservice-merseburg.de/index.php/Absorption_Schallwellen
|-valign="top"
|[4]
|DIN EN 843-2 (2007): Hochleistungskeramik – Mechanische Eigenschaften monolithischer Keramik bei Raumtemperatur – Teil 2: Bestimmung des Elastizitätsmoduls, Schubmoduls und der Poissonzahl
|-valign="top"
|[5]
|Waygate Technologies – Baker Hughes Company.: Ultraschallprüfköpfe für Fehlernachweise und Größenbestimmungen. Baker Hughes Company (2020) https://www.bakerhughesds.com/sites/g/files/cozyhq596/files/2020-07/bhcs34592-de_ultrasonic_transducers_catalog_r9.pdf (Zugriff am 06.02.2023)
|}

[[Category:Acoustic Test Methods_Ultrasonics]]

Ultrasonic Weld Inspection

2026-09-07T10:42:01Z

Oluschinski:

{{Language_sel|LANG=ger|ARTIKEL=Ultraschall-Schweißnahtprüfung}}
{{PSM_Infobox}}
Ultrasonic weld inspection
__FORCETOC__

==Weld inspection with ultrasound==

In the weld inspection with ultrasound on metals, especially on steels, testing methods are successful and established for decades in practical use. Weld inspection with polymers have diverse problems, which results of its visco-elasticity, the high damping and scattering inside the materials.

Thereby, the ultrasound experiences a high absorption (sound damping) during transmission through the polymer and comparatively low refraction of sound waves at the transition from the ultrasonic transducer over the coupling medium in the polymer.

==Principle of the angular beam==

A favoured method for the weld inspection is the angular radiation by angle-beam probes. Though the angles are mostly fixed depending on the material, which is to be tested. At the interface of transducer/material, a transformation of wave modes happens. According to the law of refraction by Snellius at the interface of two media the longitudinal wave is refracted (and reflected) as well as is also converted in a transversal wave.

[[file:Ultrasonic Weld Inspection 1.jpg|600px]]
{|
|- valign="top"
|width="50px"|'''Fig. 1''':
|width="600px"|Schematic drawing of (a) an angular radiation by means of an angle-beam probe and (b) the transformation of wave modes at the interface between probe (transducer) and the test object
|}

Therefore, in a solid specimen, two types of wave propagating: 1. the longitudinal wave (compression wave) and 2. the transversal wave (shear wave). The longitudinal wave propagates lengthwise and the transversal wave crosswise to the direction of propagation.

This process for the critical angle of the total reflectance is shown in '''Fig. 1a'''. There the refracted longitudinal wave have the critical angle of the total reflectance (red arrow) and only the transversal wave (blue arrow) propagates in the object volume, wherewith only the transversal wave exists in the material, which simplified the interpretation of the received signal. The general case for an incident angle, which deviated from the critical angle, is shown in '''Fig. 1b'''.

==Angular beaming on polymers==

The disadvantage of the angular radiation on polymers over metals is founded in the relative low difference of impedance among the transducer (with matching layer) and the polymer. Therewith, two wave modes exist in the polymeric material, which complicate the interpretation notably. Here, an analysis of the beam path helps. A normal-beam probe is shown in '''Fig. 2''' that simulate an angle-beam probe by intro-mission in a defined angle to the surface of the specimen. By means of the law of refraction by SNELLIUS (Equation (1)) and the geometrical conditions, the sound paths are calculated.

{|
|-
|width="20px"|
|width="500px"|<math>\frac{Sound velocity\; in\; the\; medium}{Angle\; in\; the\; medium}= const.</math>
|(1)
|}

For minimising the sound loss at direct coupling on polymers, between probe and specimen water will be used as coupling medium. The longitudinal wave emitted from the probe or transducer (red beam) is refracted on the sample surface and hive the incident wave in a longitudinal wave (red) and a transversal wave (green). Both sound beams are reflected at the back wall and the weld joint (dark stripe) and get off the specimen reach the ultrasound probe partly. Though, it is to see that the diameter of the probe influences importantly the size of the measurable surface of the weld joint. It is assumed, that flaws in the weld joint trigger a signal off at the ultrasound probe, because these flaws begins to oscillate with the ultrasound and beam in all directions, then more small transducer can be used.

[[file:Ultrasonic Weld Inspection 2.jpg|400px]]
{|
|- valign="top"
|width="50px"|'''Fig. 2''':
|width="600px"|Principle of ultrasonic weld inspection; the red beams stand for the incident longitudinal wave, the green ones for the transversal waves and the blue ones the reflected waves back in the coupling medium
|}

==Example for ultrasonic weld inspection on poly(methylmethacrylate) (PMMA)==

Which interpretative difficulties a measurement of weld joints is making, shows the following example. In '''Fig. 3''' the upper surface of a welded polymer sample (of two identical materials) is shown. The welding joint (WJ) is manufactured by hot plate butt welding method.

[[file:Ultrasonic Weld Inspection 3.jpg|450px]]
{|
|- valign="top"
|width="50px"|'''Bild 3''':
|width="600px"|Schema of a specimen on poly(methylmethacrylate) (abbr.: PMMA) with weld joint where copper stripes are embedded as flaws (top view)
|}

In the '''Figure 3''' the welded influence zone (WIZ) is shown (reddening), which makes difficult the evaluation of the measurement's result by changed material properties. Because of the high sound absorption and the inclined incidence of sound, the signal ('''Fig. 4''') is very noisy. By means of a sound beam analysis, the individual echoes can be assigned to the defined incidents.

[[file:Ultrasonic Weld Inspection 4.jpg|550px]]
{|
|- valign="top"
|width="50px"|'''Fig. 4''':
|width="600px"|Example of a HF-Scan at angular radiation with [[Ultrasonic Immersion Bath Technique | immersion bath technique]] in a PMMA specimen with weld joint and embedded copper stripes as flaws
|}

According to the measuring set-up, four surface echoes are found in different depths whereby one of that interfere with a (simulated) flaw, which can be confirmed by an analysis of the sound beam.

==See also==

* [[Ultrasonic Direct Coupling | Ultrasonic direct coupling]]
* [[Pulse-Echo Ultrasonic Technique | Pulse-echo ultrasonic technique]]
* [[Ultrasonic Immersion Bath Technique | Ultrasonic immersion bath technique]]
* [[Ultrasonic Runtime Measurement | Ultrasonic runtime measurement]]
* [[Ultrasound – Elastic Parameters | Ultrasound – Elastic parameters]]

==References==

{|
|-valign="top"
|[1]
|Leger, A., Deschamps, M.: Ultrasonic Wave Propagation in Non-Homogeneous Media. Springer Berlin Heidelberg (2009), (ISBN 978-3-540-89104-8)
|-valign="top"
|[2]
|Krautkrämer, J., Krautkrämer, H.: Attenuation of Ultrasonic Waves in Solids. In: Ultrasonic Testing of Materials. Springer Berlin (1990), (ISBN 978-3-662-10682-2)
|-valign="top"
|[3]
|Deutsch, V., Platte, M., Vogt, M.: Ultrasonic Testing. Fundamentals and Industrial Applications. Springer Berlin (1997), (ISBN 978-3-540-62072-9)
|}

[[Category:Acoustic Test Methods_Ultrasonics]]

Ultrasonic Waves Reflection

2026-09-07T10:41:38Z

Oluschinski:

{{Language_sel|LANG=ger|ARTIKEL=Reflexion Schallwellen}}
{{PSM_Infobox}}
Ultrasonic waves reflection
__FORCETOC__

==Physical fundamentals==

Alongside [[Transmission Sound Waves|transmission]] and [[Absorption Sound Waves|absorption]], the reflection of sound waves is a phenomenon that occurs at the external or internal [[Phase Boundary Surface|boundary surfaces]] of materials or test pieces.

The law of reflection ('''Eq. 1''') means that the angle of reflection ''β'' is identical to the angle of incidence ''α'', and both lie with the normal (plumb line) in one plane, the so-called plane of incidence. To fulfil this, the wavelength ''λ'' must be considerably greater than the distances between the scattering centres in the material.

{|
|-
|width="20px"|
|width="500px"| ''α'' = ''β'' or sin ''α'' = sin ''β''
|(1)
|}

The ultrasonic waves are altered at interfaces in terms of their wave propagation type (longitudinal or transverse wave), size or amplitude, and the direction and frequency of wave propagation ([[Dispersion|dispersion]] and mode conversion). The interface itself is formed by adjacent layers (e.g. metal or air with water) that have different characteristic impedances or acoustic impedances W or Z.

An incident sound wave is thus partially reflected at an interface and also partially transmitted or transferred to the neighbouring layer (overcoupling). The prerequisite for this is that both neighbouring layers have different sound impedances ''W'', whereby it is not the absolute value but the difference in sound impedances Δ''W'' that is decisive. In the general case, the volumes and thus the adjacent layer thicknesses are large compared to the wavelength ''λ'' of the ultrasound, which is why the sound propagation here depends only on the angle of incidence of the sound wave and the difference in sound impedances.

However, if the second medium is limited in thickness ''d'' in the direction of wave propagation (''d'' ≈ ''λ''), then the interface effectively doubles ([[Crack|cracks]], doublings and delaminations) and the behaviour of the sound waves then depends on the ratio of thickness to wavelength ''d''/''λ''.

The sound wave resistance or sound impedance of materials, as the product of [[Density|density]] ''ρ'' and [[Sound Velocity|sound velocity]] ''c'' with ''Z'' or ''W'' = ''ρ'' ''c'', is of particular importance for the reflection and [[Transmission Sound Waves|transmission behaviour]] of sound waves. This [[Material Parameter|parameter]] therefore describes the [[Elasticity|elastic]] material properties typical of the material, whereby [[Material & Werkstoff|materials]] with a high ''W'' value are described as sound-hard (Fe, Cu, Ni) and those with low ''W'' values (PMMA, Al, H2O) as sound-soft [1–4].

==Reflection of sound waves at interfaces==

When an ultrasonic wave enters from a sound-hard (''W''1) to a sound-soft (''W''2) medium or vice versa, reflection and transmission will occur, provided that the longitudinal wave strikes the interface between the two media perpendicularly ('''Fig. 1''').

[[File:Reflection_Sound-1.jpg]]
{|
|- valign="top"
|width="50px"|'''Fig. 1''':
|width="600px"|Reflection and [[Transmission Sound Waves|transmission]] at the interface between two media a) and between the [[Ultrasonic Sensors|ultrasonic sensor]] and the specimen surface b) with perpendicular sound incidence [9]
|}

The transmission content is greater when the differences between the sound impedances ''W''1 and ''W''2 are smaller. However, if the difference between ''W''1 and ''W''2 is very large, as is the case with a vacuum or air as the second medium, then a large to total content of the incident sound wave is reflected. This effect has a major influence on the detectability of [[Errors|defects]] in [[Ultrasound Testing|ultrasound testing technology]], both in the [[Pulse-Echo Ultrasonic Technique|pulse-echo ultrasonic technique]] and [[Transmission Sound Waves|transmission]] technique methods.

The reflection factor R ('''Eq. 2''') indicates how much of the incident [[Sound Pressure|sound pressure]] ''P''0 is reflected and how large the transmitted or passed content ''P''D is ('''Fig. 1a'''), whereby this [[Material Parameter|parameter]] depends significantly on the difference between the sound impedances ''W''1 and ''W''2 [4].

{|
|-
|width="20px"|
|width="500px"|<math>R=\frac{W_{2}-W_{1}}{W_{2}+W_{1}}</math>
|(2)
|}

When using longitudinal waves with vertical sensors, a large part of the sound waves can also be reflected at the [[Phase Boundary Surface|interface]] between the [[Ultrasonic Sensors|sensor]] and the workpiece if the [[Surface|surface]] is very rough and uneven and unsuitable coupling agents are used ('''Fig. 1b'''). This problem does not occur with the [[Ultrasonic Immersion Bath Technique|immersion bath]] and [[Squirter Technique|squirter techniques]] or when using [[Air-Ultrasound|air-ultrasound]]. However, since a part of the sound is always reflected back into the sensor depending on the sound impedances, the influence on the transmission signal (SE) must be minimised by using suitable damping layers [5–9]. 
By relating ''R'' to the [[Sound Pressure|sound pressure]] ''P'', this characteristic value can take on positive or negative values, whereby a negative sign for ''R'' (acoustically soft medium) indicates the reversal of the phase compared to the incident wave. When sound waves strike flat boundary surfaces perpendicularly, no wave conversion occurs, and for identical media (''W''1 = ''W''2), ''R'' = 0 and ''T'' or ''D'' = 1, i.e. there is unimpeded sound transmission.

[[File:Reflection_Sound-2.jpg]]
{|
|- valign="top"
|width="50px"|'''Fig. 2''':
|width="600px"|Reflection and [[Transmission Sound Waves|transmission]] at the interface between two media a) and between the [[Ultrasonic Sensors|ultrasonic sensor]] and the specimen surface b) with oblique sound incidence [9]
|}

If the ultrasound strikes oblique interfaces ('''Fig. 2'''), mode conversion or wave conversion, reflection, [[Transmission Sound Waves|transmission]] and [[Refraction Sound Waves|refraction]] occur in conjunction with frequency dispersion. Mode conversion is very important for some ultrasonic testing techniques, such as [[Ultrasonic Angle Beam Sensors|angle sensors]]. In this case, a transverse wave is additionally generated for both the reflected and transmitted waves. In the case of the angle sensor, depending on the difference in acoustic impedances and the angle of incidence, the longitudinal wave in medium 2 is totally reflected and the reflected transverse and longitudinal waves are attenuated in the sensor by an intermediate layer. In this case, the reflection factor ''R'' is calculated according to '''Eq. (3)''' as:

{|
|-
|width="20px"|
|width="500px"|<math>R=\frac{P_{R}}{P_{0}}=\sqrt{\frac{\frac{1}{4}[\frac{W_{1}}{W_{2}}-\frac{W_{2}}{W_{1}}]^{2} \sin ^{2}\frac{2\pi d}{\lambda}}{1+\frac{1}{4}[\frac{W_{1}}{W_{2}}-\frac{W_{2}}{W_{1}}]^{2} \sin ^{2}\frac{2\pi d}{\lambda}}}</math>
|(3)
|}

==Detectability of defects in ultrasound testing==

In ultrasonic defectoscopy, defects or discontinuities in the [[Material & Werkstoff|material]] are more easily detectable the greater the differences in sound waves (echo detectability) are (e.g. steel − air: ''R'' >> -1). On the other hand, thin layers of air already result in complete reflection of the ultrasonic wave at 1 MHz due to the large differences in ''W'', even with plane-parallel air gaps of 10 nm between the test sensor (steel) and a rough [[Surface|surface]] (air). In [[Pulse-Echo Ultrasonic Technique|pulse-echo ultrasonic technique]], the detection of the test piece thickness or the fault depth (voids, inclusions, delaminations, doublings or [[Crack|cracks]]) of discontinuities is based on the reflection of the pulsed transmitter pulse to the [[Ultrasonic Sensors|sensor]], which thus serves as both transmitter and receiver. A signal image ([[A-Scan Technique|A-scan]]) is generated from the measured time or path difference and displayed on a monitor. This A-scan (see: [[Imaging Ultrasonic Testing|imaging ultrasonic testing]]) shows the location and size of the [[Errors|defect]] in comparison to a substitute reflector (e.g. circular disc reflector). This normally allows defects (discontinuities) with a size of approx. 0.6 mm to be detected. If there are no defects, the wall thickness is determined on the basis of the rear wall echo (RE) or the defect location is indicated by total or partial reflection of the defect echo (FE) ('''Fig. 3'''). The [[Pulse-Echo Ultrasonic Technique|pulse-echo method]] can be used in [[Ultrasonic Standard Sensors|standard]], [[Ultrasonic Transmitter(S)-Receiver(E) Sensors|transmitter-receiver (SE)]] and [[Ultrasonic Angle Beam Sensors|angle testing techniques]].

[[File:Reflection Sound-3.jpg]]
{|
|- valign="top"
|width="50px"|'''Fig. 3''':
|width="600px"|Pulse-echo ultrasonic method on a test piece with [[Errors|defect]] a) and [[A-Scan Technique|A-scan]] of the surface defect (imperfection) with partial coverage of the rear wall b) with perpendicular sound incidence [9]
|}

==See also==

* [[Refraction Sound Waves|Refraction sound waves]]
* [[Dispersion]]
* [[Transmission Sound Waves|Transmission sound waves]]
* [[Absorption Sound Waves|Absorption sound waves]]
* [[Sound Emission Experimental Conditions|Sound emission experimental conditions]]

==References==

{|
|-valign="top"
|[1]
|Krautkrämer, J., Krautkrämer, H.: Ultrasonic Testing of Materials. Springer, Berlin (1990) 4th Edition, (ISBN 978-3-540-51231-8)
|-valign="top"
|[2]
|Lerch, R., Sessler, G., Wolf, D.: Technische Akustik – Grundlagen und Anwendung. Springer, Berlin (2009) (ISBN 978-3-540-49833-9)
|-valign="top"
|[3]
|Möser, M.: Technische Akustik. Springer, Berlin (2015) (ISBN 978-3-662-47704-5)
|-valign="top"
|[4]
|Matthies, K. u. a.: Dickenmessung mit Ultraschall. DVS Media Verlag, Berlin (1998) 2nd Edition (ISBN 978-3-87155-940-2; see [[AMK-Library]] under M 44)
|-valign="top"
|[5]
|Šutilov, V. A.: Physik des Ultraschalls. Springer, Berlin (2013) p. 155 ff. (ISBN 978-3-70918-750-0)
|-valign="top"
|[6]
|Deutsch, M.; Platte, V.; Vogt, M.: Ultraschallprüfung. Grundlagen und industrielle Anwendungen. Springer, Berlin (1997) (ISBN 3-540-62072-9; see [[AMK-Library]] under M 45)
|-valign="top"
|[7]
|Steeb, S. (Eds.): Zerstörungsfreie Werkstück- und Werkstoffprüfung. Expert Publishing, Ehningen (1993), 2nd p. 253 (ISBN 3-8169-0964-7; see [[AMK-Library]] under M 42)
|-valign="top"
|[8]
|Busse, G.: Non-destructive Polymer Testing. In: [[Grellmann, Wolfgang|Grellmann, W.]], [[Seidler, Sabine|Seidler, S.]] (Eds.): Polymer Testing. Carl Hanser, Munich (2022) 3rd Edition, pp. 431–495 (ISBN 978-1-56990-806-8; E-Book: ISBN 978-1-56990-805-5; see [[AMK-Library]] under A 22)
|-valign="top"
|[9]
|[[Bierögel, Christian|Bierögel, C.]]: Lecture Notes: Materials Diagnostics – Hybrid Testing Methods. Vienna University of Technology (2015)
|}

[[Category:Acoustic Test Methods_Ultrasonics]]

Ultrasonic Wall Thickness Measurement

2026-09-07T10:41:10Z

Oluschinski:

{{Language_sel|LANG=ger|ARTIKEL=Ultraschall-Wanddickenmessung}}
{{PSM_Infobox}}
Ultrasonic wall thickness measurement
__FORCETOC__

==Technical requirements==

The most important practical applications of [[Ultrasound Testing|ultrasonic testing technology]] are the [[Non-destructive Testing (NDT)|non-destructive characterisation]] of [[Material & Werkstoff|materials]] for [[Errors|defect]] detection, [[Ultrasonic Weld Inspection|weld seam testing]] and the measurement of the thickness or wall thickness of [[Plastic Component|components]] [1], some of which require special testing technology for the testing application.

Ultrasonic wall thickness measurement is an established and industrially used testing method, which has been greatly simplified and improved in terms of measurement technology, particularly through digital technology, but still requires solid knowledge and practical experience on the part of the tester [1, 2].

For test objects that are not accessible from both sides, such as pipes or containers, which may also contain production media, wall thickness measurement is only possible using [[Non-destructive Polymer Testing|non-destructive polymer testing]] methods, whereby ultrasonic wall thickness measurement has become established here, regardless of the material. The [[Pulse-Echo Ultrasonic Technique|pulse-echo technique]] with [[Ultrasonic Standard Sensors|normal]] or [[Ultrasonic Transmitter(S)-Receiver(E) Sensors|S/E sensor]] is particularly relevant from a technical point of view, although [[Ultrasonic Transmission Technique|ultrasonic transmission measurement technique]] is also applicable, but is preferred in laboratory operations and is used for [[Air-Ultrasound|air-ultrasound]].

==Physical fundamentals==

The test method for determining the wall thickness ''d'' is based on determining the sound running time ''t'' from the test head to the wall and back again, but requires knowledge of the longitudinal wave velocity ''c''L of the material to be tested at a specified test temperature ('''Eq. 1''').

{|
|- valign="top"
|width="350px"|<math>d=\frac{c_{L} \cdot t}{2}</math>
|width="50px"|(1)
|}

After converting '''Eq. (1)''', the [[Sound Velocity|sound velocity]] can then be determined from the known thickness of a test object, whereby calibration on identical material is required in both cases.

==Experimental methods and evaluation procedures==

The classic testing technique for wall thickness measurement uses either [[Pulse-Echo Ultrasonic Technique|ultrasonic pulse excitation]] with a defined pulse repetition frequency or quasi-stationary excitation of ultrasound using [[A-Scan Technique|A-scan]] display or the ''λ''/2 thickness resonance frequency ''f''R0 to determine thickness characteristics. While the resonance method is used in particular for very thin components, analogue and now digital [[A-Scan Technique|A-scan]] technique was previously the preferred method for industrial applications [1]. Simple wall thickness measurement using the single echo method is used especially for highly damping or scattering materials ('''Fig. 1a'''), as no multiple echoes are registered here. The runtime ''t'' of the ultrasound between the transmitted and reflected echoes (RE) from the back wall is evaluated on the monitor display, whereby influences from [[Adjustment|adjustment]], reading inaccuracy and echo height scaling can distort the measurement result.

[[File:US_Wall_Thickness-1.jpg]]
{|
|- valign="top"
|width="50px"|'''Fig. 1''':
|width="600px"|Ultrasonic wall thickness measurement using the pulse-echo technique as (a) single echo method and (b) multiple echo method
|}

In addition, there is the system dead time and, in the case of small thicknesses, overlaps between the high-voltage pulse of the transmitter and the first back wall echo (RE), which means that no foot point can be determined for the transmitted echo. If multiple [[Reflection Sound Waves|reflections]] occur between the [[Ultrasonic Sensors|ultrasonic sensors]] and the rear wall in homogeneous and isotropic materials, the multiple echo method ('''Fig. 1b''') can be used. In this case, the wall thickness is determined over several echoes, whereby the multiplication of the running path length must also be taken into account. One of the back wall echoes can then also be used as the starting point for the measurement. However, this preferred method can only be used when multiple echoes occur (homogeneous metallic materials) and is generally not usable in cases of high attenuation or strong scattering. For very thin walls and to suppress the transmission pulse, delay lines can also be used, which improve the close-range resolution and also allow applications on curved geometries (pipes or containers) [1–3]. In both cases, the measurement becomes much more complicated if there are corners and edges in the immediate vicinity of the measuring position [3, 4] and if there is severe erosive or corrosive damage to the rear wall. If [[Ultrasonic Transmitter(S)-Receiver(E) Sensors|S/E sensors]] are used for wall thickness measurement to increase the local resolution, a correction of the reverse path length is necessary, as the ultrasound is transmitted into the test object at an angle corresponding to the roof angle. When using the [[Ultrasonic Immersion Bath Technique|immersion bath technique]] or delay line bodies, the respective interface echo (e.g. between the delay line and the test object surface) can also be included in the evaluation.

==FreqScan evaluation method==

Even when using the immersion technique, evaluation problems arise in wall thickness measurement with highly scattering composite materials, as the actual back wall echo is difficult to separate from the signal noise [5]. It can be seen that without the use of delay distances, a highly noisy back wall signal ('''Fig. 2 a''') occurs. With a delay line ('''Fig. 2b'''), there is a significant improvement in the signal-to-noise ratio, which can be further improved by using the FreqScan evaluation method developed by [https://de.wikipedia.org/wiki/Polymer_Service_Merseburg Polymer Service GmbH Merseburg] [6].

[[File:US_Wall_Thickness-2.jpg]]
{|
|- valign="top"
|width="50px"|'''Fig. 2''':
|width="600px"|Ultrasonic wall thickness measurement using the pulse-echo ultrasonic technique on GFRP (''d'' = 34.4 mm) in direct coupling as (a) without delay and (b) with delay [5]
|}

==Equipment technology for ultrasonic wall thickness measurement==

Compared to analogue measuring systems with [[A-Scan Technique|A-scan technique]], modern digital wall thickness devices are small and handy, and the wall thickness can be read directly from the integrated monitor. These devices ('''Fig. 3a''') simplify calibration, can be switched from thickness to sound velocity measurement and, in the case of [[Ultrasonic Transmitter(S)-Receiver(E) Sensors|S/E sensors]], include correction of the path error, taking into account the respective roof angle. However, devices that include a digital display of the A-scan in addition to the alphanumeric display ('''Fig. 3b''') are preferable, as they allow the tester to check the [[Measured Value Accuracy|correctness of the measurement]]. Regardless of these advantages, the influences of coupling agent thickness, corrosion on the rear wall, fluctuating contact pressure or the test temperature must of course also be taken into account, whereby modern [[Ultrasonic Sensors|ultrasonic sensors]] often already have integrated temperature sensors [7].

[[File:US_Wanddickenmessung-3.jpg|500px]]
{|
|- valign="top"
|width="50px"|'''Fig. 3''':
|width="600px"|Digital ultrasonic wall thickness gauges (a) from [https://www.karldeutsch.de/?lang=en Karl Deutsch Prüf- und Messgeräte Bau GmbH und Co KG], Wuppertal and (b) from [https://ims.evidentscientific.com/en/flaw-detectors Olympus IMS]
|}

==Application examples==

Ultrasonic wall thickness measurement is used in the chemical industry to check wall thickness erosion, especially in pipelines, containers and tanks, as well as in shipbuilding for servicing purposes. This allows, for example, [[Surface|surface]] or selective corrosion (pitting), cavitation (voids) or erosion to be detected, differentiated and quantitatively specified.

[[File:US_Wall_Thickness-4.jpg]]
{|
|- valign="top"
|width="50px"|'''Fig. 4''':
|width="600px"|Wall thickness measurement on metal and plastic pipes and use of the results for service life prediction
|}

In pipelines used in the chemical industry or in nuclear power plants, which form a significant part of the infrastructure, increased [[Material & Werkstoff|material]] wear is recorded, regardless of the material used, particularly in the impact area ('''Fig. 4''') at pipe curvatures or bends and in the vicinity of welded joints (flow turbulence) when abrasive or erosive media are transported. In the case of metallic pipes, erosion or corrosive effects often occur here, while in the case of plastic pipes or containers, damage to the inliner occurs, which leads to exposure of the [[Fibre-reinforced Plastics#Types of reinforcing plastics|reinforcing fibre]] and a reduction in the initial wall thickness ''d''0 (see '''Fig. 4'''). With prescribed cyclical inspection (3 to 6 months) of the residual wall thickness, these pipe sections can be replaced prophylactically if the permissible residual wall thickness ''d''zul is known, thereby avoiding any consequential damage. If these measuring positions are difficult to access due to design conditions and/or thermal insulation, these [[Ultrasonic Sensors|ultrasonic sensors]] can also be installed in a stationary manner, analogous to the acoustic emission sensor technology used in nuclear power plants, and the wall thickness is determined permanently or cyclically at an identical position [8].

A special form of thickness measurement is the determination of the layer thicknesses of paint coatings or plastic insulation on metallic base materials using ultrasound, which, however, requires a special measurement and evaluation methodology [3].

==See also==

* [[Acoustic Properties|Acoustic properties]]
* [[Ultrasound Modulation|Ultrasound modulation]]
* [[Air-Ultrasound − Device Technology|Air-Ultrasound − Device technology]]
* [[HF-Scan|HF-scan]]
* [[Sound Pressure|Sound pressure]]

==References==

{|
|-valign="top"
|[1]
|Matthies, K. u. a.: Dickenmessung mit Ultraschall. DVS-Verlag GmbH, Berlin, 2nd Edition (1998), (ISBN 3-87155-940-7; see [[AMK-Library]] under M 44)
|-valign="top"
|[2]
|Deutsch, V., Platte, M., Vogt, M.: Ultraschallprüfung – Grundlagen und industrielle Anwendungen. Springer, Berlin (2012), (ISBN 978-3-642-63864-0; see [[AMK-Library]] under M 45)
|-valign="top"
|[3]
|Gevatter, H.-J., Grünhaupt, U. (Eds.): Handbuch der Mess- und Automatisierungstechnik in der Produktion. Springer, Berlin, 2nd Edition (2006), (ISBN 978-3-540-21207-2)
|-valign="top"
|[4]
|DIN EN 14127 (2011-04): Non-destructive Testing – Ultrasonic Thickness Measurement (withdrawn; replaced by DIN EN ISO 16809 (2025-09)
|-valign="top"
|[5]
|Sirch, C., Oluschinski, A., [[Bierögel, Christian|Bierögel, C.]], [[Grellmann, Wolfgang|Grellmann, W.]]: Ultraschallprüfung von Kunststoffbauteilen. 12. Tagung „Problemseminar Deformation und Bruchverhalten von Kunststoffen“, Merseburg, June 24–26, 2009, Proceedings CD-ROM
|-valign="top"
|[6]
|Sirch, C., Oluschinski, A., Bierögel, C., Rufke, B., zur Horst-Meyer, S., [https://www.researchgate.net/profile/Wolfgang-Grellmann Grellmann, W.]: Ultraschall-Messungen an Grenzflächen in GfK-Thermoplast-Verbunden. 11. Tagung „Problemseminar Deformation und Bruchverhalten von Kunststoffen“, Merseburg, June 20–22, 2007, Proceedigs CD-ROM (ISBN 978-3-86010-918-2) pp. 429−430
|-valign="top"
|[7]
|zur Horst-Meyer, S.: SONOWALL – Wanddickenmessungen mit Ultraschall. DGZfP-Jahrestagung „Zerstörungsfreie Werkstoffprüfung“ (2010), Erfurt, P54 [http://jt2010.dgzfp.de/Portals/jt2010/BB/p54.pdf Download as pdf]
|-valign="top"
|[8]
|Mück, A., Imhof, D.: Dauerüberwachung der Wanddicke von Rohrleitungen mit Ultraschall. DGZfP-Jahrestagung „Zerstörungsfreie Werkstoffprüfung“ (2015), Salzburg, Österreich, A1
|}

[[Category:Acoustic Test Methods_Ultrasonics]]