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	* Qualification of basic mechanical tests for [[Polymer Testing \| polymer testing]] to demonstrate stress-induced property changes that can lead to loss of [[Ductility Plastics\| ductility]] or a decrease in [[Strength\|strength]],		* Qualification of basic mechanical tests for [[Polymer Testing \| polymer testing]] to demonstrate stress-induced property changes that can lead to loss of [[Ductility Plastics\| ductility]] or a decrease in [[Strength\|strength]],
	* Determination of material damage as a precursor to the ultimate failure of plastic components (see: [[Plastic Component \| plastic component]] and [[Component Testing \| component testing]]) and		* Determination of material damage as a precursor to the ultimate failure of plastic components (see: [[Plastic Component \| plastic component]] and [[Component Testing \| component testing]]) and
	* Representation of damage kinetics and dominant structurally influenceable [[Deformation ~~Mechanism~~\|damage mechanisms]] to describe material limit states or diagnostic functions for damage mechanics.		* Representation of damage kinetics and dominant structurally influenceable [[Deformation Mechanisms\|damage mechanisms]] to describe material limit states or diagnostic functions for damage mechanics.

	==Hybrid methods and Instrumentation of testing methods==		==Hybrid methods and Instrumentation of testing methods==

Oluschinski: Created page with "{{Language_sel|LANG=ger|ARTIKEL=Hybride Methoden}} {{PSM_Infobox}} Hybrid methods of plastic diagnostics FORCETOC ==Limitations of conventional polymer testing== In addition to suitable material properties that can be used in design, knowledge of stress-induced material damage is an essential prerequisite for the dimensioning of plastic components and the practical use of Plastics | pl..."

2025-12-02T08:52:50Z

Created page with "{{Language_sel|LANG=ger|ARTIKEL=Hybride Methoden}} {{PSM_Infobox}} Hybrid methods of plastic diagnostics __FORCETOC__ ==Limitations of conventional polymer testing== In addition to suitable material properties that can be used in design, knowledge of stress-induced material damage is an essential prerequisite for the dimensioning of plastic components and the practical use of Plastics | pl..."

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{{Language_sel|LANG=ger|ARTIKEL=Hybride Methoden}}
{{PSM_Infobox}}
Hybrid methods of plastic diagnostics
__FORCETOC__

==Limitations of conventional polymer testing==

In addition to suitable material properties that can be used in design, knowledge of stress-induced material damage is an essential prerequisite for the dimensioning of [[Plastic Component | plastic components]] and the practical use of [[Plastics | plastics]]. In-depth information about damage processes and [[Deformation Mechanisms|deformation mechanisms]] is required, especially from the perspective of consistent, optimal use of material resources. The damage-specific [[Material Parameter | parameters]] determined under mechanical, media and thermal stress provide material developers and designers with information about relevant [[Stress | stress]] limits and users with information about the remaining service life or functionality of a component. On the other hand, damage and accidents attributable to the [[Failure Analysis – Basics | failure of plastic components]] prove that material characterisation is often too one-sided and that the safety and quality characteristics used to date are not yet sufficient.

From the perspective of modern materials development, there is therefore a need for material-descriptive, structurally or morphologically based parameters that provide information about stress limits depending on complex load conditions and, in conjunction with suitable material laws, enable the selection and dimensioning of plastics in a manner appropriate to the material. Conventional test methods such as [[Tensile Test | tensile testing]] or [[Bend Test | bending testing]] cannot meet these requirements, as the parameters determined are not always structurally or physically justifiable. One example of this is microdamage (see [[Micro-Damage Limit | micro-damage limit]]), which occurs in the non-linear viscoelastic deformation range (see: [[Elasticity | elasticity]]) and cannot be derived from the stress–strain diagrams (see: [[Tensile Test|tensile test]]) determined.

==Development trends in the application of mechanical methods==

The development of innovative new [[Plastics | plastics]] and [[Composite Materials Testing|composite materials]] tailored to specific requirements is currently giving rise to the following trends in the application of conventional mechanical testing methods:

* Qualification of basic mechanical tests for [[Polymer Testing | polymer testing]] to demonstrate stress-induced property changes that can lead to loss of [[Ductility Plastics| ductility]] or a decrease in [[Strength|strength]],
* Determination of material damage as a precursor to the ultimate failure of plastic components (see: [[Plastic Component | plastic component]] and [[Component Testing | component testing]]) and
* Representation of damage kinetics and dominant structurally influenceable [[Deformation Mechanism|damage mechanisms]] to describe material limit states or diagnostic functions for damage mechanics.

==Hybrid methods and Instrumentation of testing methods==

Methodologically, there are two main approaches, which are sometimes used in combination:

* Application of hybrid experimental methods, i.e. the in-situ coupling of basic mechanical and [[Fracture Mechanical Testing|fracture mechanics tests]] with [[Non-destructive Testing (NDT)|non-destructive testing methods]] to increase the informative value of material properties and to formulate damage functions or limit values, e.g. by means of mechanodielectrometry, [[Acoustic Emission|acoustic emission analysis]], [[Thermography|thermography]], computed tomography (radiographic testing) or [[Ultrasound Testing|ultrasonic testing]], and
* Qualification of basic mechanical experiments through [[Electronic Instrumentation|instrumentation]] and the application of improved measurement and evaluation techniques such as video extensometry, [[Laser Extensometry|laser extensometry]] or field measurement techniques in conjunction with event- and structure-related interpretation of the [[Deformation|deformation phases]] of [[Plastics|plastics]], which simultaneously results in increased requirements for the experimental control of these tests.

The overview in the '''Figure''' shows that, regardless of the selected [[Stress|stress]] conditions for such hybrid experimental investigations, continuous recording of the stress parameters is necessary. The test methods shown in the sensor block as examples must meet the following requirements:

* sufficient sensitivity and applicability of the test method for the plastic to be investigated,
* sufficient structural sensitivity or selectivity for the dominant [[Deformation Mechanisms|damage mechanisms]], and
* the deformation behaviour of the plastic should not be influenced by the sensors used as far as possible.

[[file:HybridMethods_Figure.jpg|650px]]
{|
|- valign="top"
|width="50px"|'''Figure''':
|width="600px" |Hybrid methods for [[Polymer Testing|polymer testing]] and [[Polymer Diagnostic|polymer diagnostics]]
|}

==Requirements for test specimens==

In [[Polymer Testing|polymer testing]], experimental investigations are carried out in the field of conventional mechanical testing on [[Multipurpose Test Specimen | multipurpose test specimens]] in accordance with ISO 3167 and in the field of fracture mechanics testing (see: [[Fracture Mechanical Testing | fracture mechanical testing]]) on CT-specimens (see: [[Compact Tension (CT) Specimen | compact tension (CT) specimens]]).

Measuring marks (targets) are attached to the tensile test specimen ([[Multipurpose Test Specimen|multipurpose test specimen]]), for example, to enable the use of the [[Laser Extensometry|laser extensometry]] method. Up to 63 targets can be applied to the test specimen to determine the local deformation behaviour. The minimum target spacing is 1 mm. When 10 targets are applied, the integral stress–strain diagram and 9 local stress–strain diagrams for each measurement zone or a selected number of zones are obtained. The CT test specimen can be prepared in a similar manner, but a different laser extensometer ([[Laser Double-Scanner|laser double-scanner]] or [[Laser Multi-Scanner|laser multi-scanner]]) is used.

==Increasing the informativeness of hybrid methods==

'''Parameter block'''

The parameter block contains, for example, the applied force or the cross-sectional stress. To determine the [[Material Value|characteristic values]] on [[Compact Tension (CT) Specimen|CT test specimens]], the load-line displacement and [[Crack Initiation|crack expansion]] are required as direct [[Measured Variable|measured variables]]. In addition to time and [[Velocity|speed]], the stress variables listed include temperature and air humidity (see: [[Test Climate|test climate]]), which have a decisive influence on the characteristic value.

'''Sensor block'''

Due to the limited [[Energy Release Rate | energy release rate]] in [[Plastics|plastics]], the use of various [[Non-destructive Testing (NDT)|non-destructive testing (NDT)]] methods is appropriate.

The sensor block lists the following examples:

* [[Acoustic Emission|Acoustic emission]]
* [[Laser Extensometry|Laser extensometry]]
* [[Ultrasound Testing|Ultrasound method]]
* Video thermography
* Dielectrometry and
* Volume dilatometry

The aim of this approach is to meet the increasing demands on the informative value of mechanical material properties from [[Quasi-static Test Methods|quasi-static test methods]]. A further aim is to enable an event-related interpretation of [[Deformation|deformation]] and [[Fracture Behaviour|fracture behaviour]], regardless of the approach and load conditions.

Although many [[Non-destructive Polymer Testing|non-destructive testing methods]] meet these requirements in principle, contactless and inertial sensor technologies should be preferred whenever possible. In hybrid methods, examples, the advantages and informative potential of such hybrid testing methods for [[Polymer Testing|polymer testing]] and [[Polymer Diagnostic|diagnostics]] are illustrated using various examples.

==See also==

* [[Hybrid Methods, Examples|Hybrid methods, examples]]
* [[Polymer Diagnostic | Polymer diagnostic]]
* [[Non-destructive Polymer Testing | Non-destructive polymer testing]]
* [[Non-destructive Testing (NDT)|Non-destructive testing (NDT)]]

'''References'''

* [[Bierögel,_Christian|Bierögel, C.]]: Hybrid Methods of Polymer Diagnostics. In: [[Grellmann, Wolfgang|Grellmann, W.]], [[Seidler, Sabine|Seidler, S.]] (Eds.): Polymer Testing. Carl Hanser, Munich (2022) 3rd Edition, pp. 497 – 513 (ISBN 978-3-446-44718-9; E-Book: ISBN 978-3-446-48105-3; see [[AMK-Büchersammlung | AMK-Library]] under A 23)
* [https://www.researchgate.net/profile/Wolfgang-Grellmann Grellmann, W.], Langer, B.: Methods for Polymer Diagnostics for the Automotive Industry. Materialprüfung 55 (2013) pp. 17–22 [https://www.polymerservice-merseburg.de/fileadmin/inhalte/psm/veroeffentlichungen/Methods_for_Polymer_Diagnostics_for_the_Automotive_Industry__Grellmann_Langer_2013_.pdf Download as pdf]
* [https://de.wikipedia.org/wiki/Wolfgang_Grellmann Grellmann, W.]: New Developments in Toughness Evaluation of Polymers and Compounds by Fracture Mechanics. In: Grellmann, W., Seidler, S. (Eds.): Deformation and Fracture Behaviour of Polymers. Springer, Berlin Heidelberg (2001) pp. 3–26, (ISBN 3-540-41247-6; see [[AMK-Büchersammlung | AMK-Library]] under A 6)
* Osswald, T. A., [[Menges, Georg|Menges, G.]]: Materials Science of Polymers for Engineers. Carl Hanser, Mnich Vienna 3rd Edition (2012) (ISBN 978-1-56990-514-2; see [[AMK-Büchersammlung | AMK-Library]] under G 55)
* Roberts, J.: A Critical Strain Design Limit for Thermoplastics. Materials & Design 4 (1983) pp. 791–793
* [[Menges, Georg|Menges, G.]], Wiegand, E., Pütz, D., Maurer, F.: Ermittlung der kritischen Dehnung teilkristalliner Thermoplaste. Kunststoffe 65 (1975) pp. 368–371
* Schreyer, G. W., Bartnig, K., Sander, M.: Bewertung von Schädigungseffekten in Thermoplasten durch simultane Messung der Spannungs-Dehnungs-Charakteristik und der dielektrischen Eigenschaften. Teil 1: Schädigungseffekte während der mechanischen Belastung und Möglichkeiten der experimentellen Bewertung. Materialw. und Werkstofftechnik 27 (1996) pp. 90–95
* Bierögel, C., Grellmann, W.: Evaluation of Thermal and Acoustic Emission of Composites by Means of Local Strain Measurements. ECF 9, European Confrence on Fracture, Varna 21.–25. September 1992, Proceedings Vol. 1 (1992) pp. 242–247
* Cowley, K. D., Beaumont, P. W. R.: Modeling Problems of Damage at Nothes and the Fracture Stress of Carbon-fiber/Polymer Composites: Matrix, Temperature and Residual Stress Effects. Composites Science and Technology 57 (1997) pp. 1309–1329
* Bartnig, K., Bierögel, C., Grellmann, W., Rufke, B.: Anwendung der Schallemission, Thermografie und Dielektrometrie zur Bewertung des Deformationsverhaltens von Polyamiden. Plaste und Kautschuk 39 (1992) pp. 1–8
* Bierögel, C., Grellmann, W.: Determination of Local Deformation Behaviour of Polymers by Means of Laser Extensometry. In: Grellmann, W., [[Seidler,_Sabine|Seidler, S.]] (Eds.): Deformation and Fracture Behaviour of Polymers. Springer, Berlin Heidelberg (2001) pp. 365–384, (ISBN 978-3-540-41247-2; siehe [[AMK-Büchersammlung | AMK-Library]] under A 7)
* Busse, G.: Hybride Verfahren in der zerstörungsfreien Prüfung (ZfP): Prinzip und Anwendungsbeispiele. In: Buchholz, O. W., Geisler, S. (Eds.): Herausforderung durch den industriellen Fortschritt. Verlag Stahleisen GmbH, Düsseldorf (2003) pp. 18–25, (ISBN 3-514-00703-9; see [[AMK-Büchersammlung | AMK-Library]] under M 11)
* Grellmann, W., Bierögel, C.: Laserextensometrie anwenden. Materialprüfung 40 (1998) pp. 452–459
* Markowski, W.: Ein neues Prinzip der Werkstoffprüfmaschine. Materialprüfung 32 (1990) pp. 144–148
* Bierögel, C., Fahnert, T., Grellmann, W.: Deformation Behaviour of Reinforced Polyamide Materials Evaluated by Laser Extensometry and Acoustic Emission Analysis. Strain Measurement in the 21St Century, Lancaster (UK) 5.–6. September 2001, Proceedings (2001) 56–59 [https://www.polymerservice-merseburg.de/fileadmin/inhalte/psm/veroeffentlichungen/Bieroegel_Deformation_Behaviour_of_Reinforced_Polyamide_Materials.pdf Download as pdf]

[[category: Hybrid Methods | Hybrid Methods]]
[[category: Laser Extensometry | Laser Extensometry]]
[[category: Morphology and Micromechanics | Morphology and Micromechanics]]

Hybrid Methods - Revision history

Oluschinski at 05:24, 15 December 2025