Oluschinski at 08:00, 12 January 2026

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	{{Language_sel\|LANG=ger\|ARTIKEL=Schallemission}}		{{Language_sel\|LANG=ger\|ARTIKEL=Schallemission Experimentelle Bedingungen}}
	{{PSM_Infobox}}		{{PSM_Infobox}}
	<span style="font-size:1.2em;font-weight:bold;">Sound emission experimental conditions</span>		<span style="font-size:1.2em;font-weight:bold;">Sound emission experimental conditions</span>

Oluschinski at 13:25, 12 December 2025

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	It can be seen from '''Fig. 4''' that the mass of the sensor has a significant influence on the result of the [[Sound Emission ~~Test~~\|sound emission test]]. Up to an additional mass of 36 g, the hit numbers drop sharply and, with a further increase, result in an almost constant level of hit numbers.		It can be seen from '''Fig. 4''' that the mass of the sensor has a significant influence on the result of the [[Sound Emission Testing\|sound emission test]]. Up to an additional mass of 36 g, the hit numbers drop sharply and, with a further increase, result in an almost constant level of hit numbers.

	==Linear location measurements==		==Linear location measurements==
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	\|[3]		\|[3]
	\|Bierögel, C.: Zur Problematik der Schallemissionsanalyse an verstärkten Thermo- und Duroplasten. Dissertation, Technische Hochschule Leuna-Merseburg (1984)		\|[[Bierögel, Christian\|Bierögel, C.]]: Zur Problematik der Schallemissionsanalyse an verstärkten Thermo- und Duroplasten. Dissertation, Technische Hochschule Leuna-Merseburg (1984)
	\|-valign="top"		\|-valign="top"
	\|[4]		\|[4]
	\|Wessolek, U.: Untersuchungen zur Berücksichtigung der Dämpfung auf die Ergebnisse der Schallemissionsanalyse bei kurzfaserverstärkten Plasten. Master Thesis, Technische Hochschule Leuna-Merseburg (1981)		\|Wessolek, U.: Untersuchungen zur Berücksichtigung der Dämpfung auf die Ergebnisse der Schallemissionsanalyse bei kurzfaserverstärkten Plasten. Master Thesis, [https://de.wikipedia.org/wiki/Technische_Hochschule_Leuna-Merseburg Technische Hochschule Leuna-Merseburg] (1981)
	\|}		\|}

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

Oluschinski: Created page with "{{Language_sel|LANG=ger|ARTIKEL=Schallemission}} {{PSM_Infobox}} Sound emission experimental conditions FORCETOC ==General== Sound emission testing is used on plastics to investigate damage behaviour and locate sources of acoustic emissions in components, and in materials testing and development to characterise dominant Deform..."

2025-12-05T13:31:50Z

Created page with "{{Language_sel|LANG=ger|ARTIKEL=Schallemission}} {{PSM_Infobox}} Sound emission experimental conditions __FORCETOC__ ==General== Sound emission testing is used on plastics to investigate damage behaviour and locate sources of acoustic emissions in components, and in materials testing and development to characterise dominant Deform..."

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{{Language_sel|LANG=ger|ARTIKEL=Schallemission}}
{{PSM_Infobox}}
Sound emission experimental conditions
__FORCETOC__

==General==

[[Sound Emission Testing|Sound emission testing]] is used on [[Plastics|plastics]] to investigate damage behaviour and locate sources of acoustic emissions in [[Plastic Component|components]], and in [[Materials Testing|materials testing]] and development to characterise dominant [[Deformation Mechanisms|damage mechanisms]], to represent the temporal damage kinetics and to determine damage limits, the results of which can be applied constructively in damage mechanics. For this purpose, various evaluation methods of [[Sound Emission Analysis|sound emission analysis]], such as amplitude, energy or [[Frequency Analysis|frequency analysis]], as well as simple characteristic values (hits, events or impulses) are used to represent damage development [1, 2].

[[Sound Emission|Sound emissions]] or [[Acoustic Emission|acoustic emissions]] always occur in solids when certain critical material stresses are exceeded ([[Crack|microcracks]], fibre breaks, delamination and debonding, see: [[Fibre-reinforced Plastics Fracture Model|fibre-reinforced plastics fracture model]]), elastic energy is emitted in the form of mechanical stress waves, which propagate in the test object primarily as spherical volume waves ('''Fig. 1''') [1]. In geometrically limited test objects, a mode conversion then occurs at the [[Surface|surface]], which makes it possible to register the [[Acoustic Emission|acoustic emission]] by means of surface or Rayleigh waves even at a greater distance from the sound emission source location.

[[File:Sound Emission ExpCond-1.jpg]]
{|
|- valign="top"
|width="50px"|'''Fig. 1''':
|width="600px"|Wave mode conversion in confined test objects (a) and surface wave behaviour (b)
|}

==Frequency response of ultrasonic sensors==

However, the propagation of ultrasonic waves in the [[Material & Werkstoff|material]] (see: [[Ultrasound Testing|ultrasound testing]]) depends largely on the transmission behaviour of the measuring chain, which consists of the ultrasonic receiver, the preamplifier and main amplifier, and the filters used. As a result, the original signal undergoes numerous changes due to frequency [[Dispersion|dispersion]], [[Ultrasonic Waves Reflection|reflection]] and scattering, causing the recorded measurement signal to differ significantly from the source signal. This means that the original square wave pulse becomes a long signal that slowly rises and falls.

Other reasons for changes to the original signal include:

* Material-inherent loss mechanisms
* [[Ultrasonic Sensors|Sensor influences]], especially directional characteristics and frequency ('''Fig. 2''')
* Interference with the useful signal by extraneous noise
* [[Viscosity]], layer thickness and damping behaviour of the coupling medium
* Surface quality of the [[Plastic Component|component]] or [[Specimen|test specimen]]
* Contact pressure between transducer and [[Surface|surface]]

[[File:Sound Emission ExpCond-2.jpg|450px]]
{|
|- valign="top"
|width="50px"|'''Fig. 2''':
|width="600px"|Frequency response of different sensors (a) and their directional characteristics (b)
|}

==Distance between the measuring point and the sound source==

However, the signal received is also significantly influenced by the measurement location and the mass of the sensor in relation to the test specimen [3]. '''Figure 3''' shows the influence of the change in measurement location distance x from a specified predetermined breaking point for polypropylene ([[Plastics – Symbols and Abbreviated Terms|abbreviation]]: PP) and polyamide 6 ([[Plastics – Symbols and Abbreviated Terms|abbreviation]]: PA), each with 30 m.-% short glass fibres.

[[File:Schallemission_exp_Bedingungen_3.jpg|450px]]
{|
|- valign="top"
|width="50px"|'''Fig. 3''':
|width="600px"|Dependence of registered hits on measurement distance x
|}

If the sensor is located directly above the sound source, the maximum number of hits is measured for both [[Material & Werkstoff|materials]] with [[Notch|notches]], which is mainly based on the registered volume waves. As the distance increases, the heat number decreases significantly and approaches an asymptote at x = 30 mm. Since small changes in the exact position near the source location have a greater effect, the scatter of the [[Measured Value|measured values]] is significantly higher here. If the sensitivity of the sensor is sufficient, the sensor should therefore always be at a sufficient distance from the known sound source.

==Influence of the intrinsic mass of the sound emission sensor==

When a BRÜEL&KJAER 8313 resonant acoustic emission sensor with an intrinsic mass of 16 g is positioned centrally, a heat count of approx. 7,500 is recorded for polyamide with 20 m-% short glass fibres until [[Fracture|fracture]] of the test [[Specimen|specimen]] in the [[Tensile Test|tensile test]] ('''Fig. 4'''). By attaching an additional mass ''m''z to the opposite side of the test specimen, the increase in the dead weight of the sensor used is simulated in the [[Tensile Test|tensile tests]].

[[File:Schallemission_exp_Bedingungen_4.jpg|450px]]
{|
|- valign="top"
|width="50px"|'''Fig. 4''':
|width="600px"|Dependence of registered hits on the mass mz of the sound detector
|}

It can be seen from '''Fig. 4''' that the mass of the sensor has a significant influence on the result of the [[Sound Emission Test|sound emission test]]. Up to an additional mass of 36 g, the hit numbers drop sharply and, with a further increase, result in an almost constant level of hit numbers.

==Linear location measurements==

If two identical BRÜEL&KJAER 8313 sensors (pair) are used to measure the [[Acoustic Emission|acoustic emissions]], the result for polyamide with 25 % glass fibres is shown in '''Fig. 5'''. One sensor ''m''af is fixed directly near the clamping point, taking into account the injection point, while the location of the other sensor ''m''av is varied up to the centre of the test specimen ''l''/2. It can be seen that comparable hit numbers are only measured in the centre of the test specimen and when both sensors are positioned at the [[Specimen Clamping|clamping point]], which is particularly important to note when performing linear location measurements.

[[File:Schallemission_exp_Bedingungen_5.jpg|450px]]
{|
|- valign="top"
|width="50px"|'''Fig. 5''':
|width="600px"|Dependence of registered hits on the position of the sound sensors
|}

==See also==

* [[Acoustic Emission|Acoustic emission]]
* [[Sound Emission|Sound emission]]
* [[Sound Emission Analysis|Sound emission analysis]]
* [[Sound Emission Testing|Sound emission testing]]
* [[Sound Velocity|Sound velocity]]
* [[Ultrasound Birefringence|Ultrasound birefringence]]
* [[Ultrasonic Sensors|Ultrasonic sensors]]

'''References'''

{|
|-valign="top"
|[1]
|Bardenheier, R.: Schallemissionsuntersuchungen an polymeren Verbundwerkstoffen – Part I: Das Schallemissionsmessverfahren als quasi-zerstörungsfreie Werkstoffprüfung. Zeitschrift für Werkstofftechnik 11 (1980) 41–46
|-valign="top"
|[2]
|Bohse, J.: Acoustic Emission Characteristics of Micro-Failure Processes in Polymer Blends and Composites. Composites Science and Technology 60 (2000) 1213–1226; https://doi.org/10.1016/S0266-3538(00)00060-9
|-valign="top"
|[3]
|Bierögel, C.: Zur Problematik der Schallemissionsanalyse an verstärkten Thermo- und Duroplasten. Dissertation, Technische Hochschule Leuna-Merseburg (1984)
|-valign="top"
|[4]
|Wessolek, U.: Untersuchungen zur Berücksichtigung der Dämpfung auf die Ergebnisse der Schallemissionsanalyse bei kurzfaserverstärkten Plasten. Master Thesis, Technische Hochschule Leuna-Merseburg (1981)
|}

[[Category:Acoustic Test Methods_Ultrasonics]]

Sound Emission Experimental Conditions - Revision history

Oluschinski at 08:00, 12 January 2026

Oluschinski at 13:25, 12 December 2025