Oluschinski at 13:26, 12 December 2025

2025-12-12T13:26:54Z

← Older revision		Revision as of 15:26, 12 December 2025
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	* [[Sound Velocity\|Sound velocity]]		* [[Sound Velocity\|Sound velocity]]
	* [[Non-destructive Testing (NDT)\|Non-destructive testing (NDT)]]		* [[Non-destructive Testing (NDT)\|Non-destructive testing (NDT)]]
	* [[Sound ~~Testing~~\|Sound ~~testing~~]]		* [[Sound Test\|Sound test]]

Oluschinski: Created page with "{{Language_sel|LANG=ger|ARTIKEL=Akustische Eigenschaften}} {{PSM_Infobox}} Acoustic properties FORCETOC ==Fundamentals== The acoustic properties are essentially represented by the material values sound velocity and acoustic damping. They are closely linked to the mechanical [[Material Parameter|material parameters] modulus of elasticity (abbreviated to m..."

2025-11-28T12:06:02Z

Created page with "{{Language_sel|LANG=ger|ARTIKEL=Akustische Eigenschaften}} {{PSM_Infobox}} Acoustic properties __FORCETOC__ ==Fundamentals== The acoustic properties are essentially represented by the material values sound velocity and acoustic damping. They are closely linked to the mechanical material parameters] [[Elastic Modulus|modulus of elasticity (abbreviated to m..."

New page

{{Language_sel|LANG=ger|ARTIKEL=Akustische Eigenschaften}}
{{PSM_Infobox}}
Acoustic properties
__FORCETOC__

==Fundamentals==

The acoustic properties are essentially represented by the [[Material Value|material values]] [[Sound Velocity|sound velocity]] and acoustic damping. They are closely linked to the mechanical [[Material Parameter|material parameters] [[Elastic Modulus|modulus of elasticity]] (abbreviated to modulus ''E'') and [[Poisson's Ratio|Poisson's ratio]], as well as [[Toughness|toughness]]. The relationship between the sound velocity ''v'', the modulus of elasticity ''M'' and the Poisson's ratio ''µ'' is shown in the following equation:

{|
|-
|width="20px"|
|width="500px" | <math> v=\sqrt{\frac{M}{\rho }}\cdot f(\mu)</math>.
|(1)
|}

Here, ''M'' is the modulus, which can be the [[Elastic Modulus|elastic modulus]], [[Shear Modulus|shear modulus]], or [[Energy Elasticity|compression modulus]], depending on the type of excitation, and ''ρ'' is the mass density (see: [[Density|density]]) of the [[Material & Werkstoff|material]]. In the case of longitudinal waves (i.e., wave propagation and particle vibrations are parallel), '''Eq. (1)''' becomes

{|
|-
|width="20px"|
|width="500px" | <math> v=\sqrt{\frac{E}{\rho}\cdot \frac{1-\mu}{(1+\mu)(1-2\mu)}}</math>.
|(2)
|}

==Acoustic damping and acoustic damping coefficient==

Due to the internal friction of the volume elements when the wave passes through the medium, acoustic damping shows an exponential dependence of the sound intensity:

{|
|-
|width="20px"|
|width="500px" | <math> I(x)=I_{0}\ e^{-2\alpha x}</math>.
|(3)
|}

The factor 2 arises from the double sound path in the [[Pulse-Echo Ultrasonic Technique|pulse-echo ultrasonic method]]. The factor ''α'' in the exponent of '''Eq. (3)''' is the acoustic damping coefficient; it has the dimension 1/m and thus represents a material-specific [[Material Value|characteristic value]], which, however, depends on the measurement frequency:

{|
|-
|width="20px"|
|width="500px" | <math> \alpha = \alpha (\omega) \!</math>.
|(4)
|}

==Temperature dependence of acoustic properties==

[[Plastics]] in particular have acoustic and mechanical properties that are highly dependent on temperature, which influences the [[Viscoelastic Material Behaviour|viscoelastic behaviour]] and damping ('''Eq. 5''') of these [[Material & Werkstoff|materials]] in particular.

{|
|-
|width="20px"|
|width="500px" | <math> \alpha = \frac{4\eta (T)}{3\rho c^3}\omega^2</math>.
|(5)
|}

The following '''Table''' lists some [[Sound Velocity|sound velocities]] and specific damping values for selected [[Material & Werkstoff|materials]].

{| border="1px" style="border-collapse:collapse"
!! style="width:200px; background:#DCDCDC" | material
!! style="width:200px; background:#DCDCDC" | sound velocity (long.) vs (m s-1)
!! style="width:200px; background:#DCDCDC" | specific damping V (dB mm-1)
|-
|steel
|style="text-align:center" | 5,900
|style="text-align:center" | 0.25
|-
|aluminium
|style="text-align:center" | 6,400
|style="text-align:center" | 0.13
|-
|brass
|style="text-align:center" | 4,300
|style="text-align:center" | 0.15
|-
|synthetic rubber
|style="text-align:center" | 1,460
|style="text-align:center" | 4.12
|-
|PMMA
|style="text-align:center" | 2,540
|style="text-align:center" | 0.31
|-
|PS
|style="text-align:center" | 2,350
|style="text-align:center" | 2.07
|-
|PVC
|style="text-align:center" | 2,300
|style="text-align:center" | 1.85
|-
|PA 6
|style="text-align:center" | 2,570
|style="text-align:center" | 2.38
|-
|PP
|style="text-align:center" | 2,550
|style="text-align:center" | 2.26
|-
|PE
|style="text-align:center" | 1,800
|style="text-align:center" | 2.26
|-
|Derakane 411
|style="text-align:center" | 2,400
|style="text-align:center" | 0.55
|-
|Derakane 470
|style="text-align:center" | 2,700
|style="text-align:center" | 0.33
|-
|Derakane 411 (36 M.-% GF)
|style="text-align:center" | 2,510
|style="text-align:center" | 0.70
|-
|Derakane 411 (70 M.-% GF)
|style="text-align:center" | 3,050
|style="text-align:center" | 0.50
|}

==See also==

* [[Acoustic Emission|Acoustic emission]]
* [[Sound Velocity|Sound velocity]]
* [[Non-destructive Testing (NDT)|Non-destructive testing (NDT)]]
* [[Sound Testing|Sound testing]]

'''References'''

* Šutilov, V. A.: Physik des Ultraschalls. Akademie Verlag, Berlin (1984) (ISBN 978-3-7091-8750-0)
* Šutilov, V. A.; Hauptmann, P.: Physik des Ultraschalls. Springer Wien (2012) (ISBN 978-3-7091-8751-7)
* Kuttruff, H.: Akustik – Eine Einführung. S. Hirzel Verlag, Stuttgart Leipzig (2004)(ISBN 978-3-7776-1244-7)
* Koschkin, N. I., Schirkewitsch, M. G.: Elementare Physik. Akademie Verlag, Berlin (1987) (ISBN 978-3-4461-4893-2)

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

Acoustic Properties - Revision history

Oluschinski at 13:26, 12 December 2025