Oluschinski: Created page with "{{Language_sel|LANG=ger|ARTIKEL=ELS-Prüfkörper}} {{PSM_Infobox}} ELS-specimen FORCETOC ==General remarks== The Anglo-Saxon abbreviation ELS stands for ‘End-Loaded Split’. The ELS-specimen is used to determine the interlaminar fracture toughness of Mode II loading [1]. ==Test specimen shape== Similar to the double cantilever beam (DCB) test (see also: DCB-specimen), a..."

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Created page with "{{Language_sel|LANG=ger|ARTIKEL=ELS-Prüfkörper}} {{PSM_Infobox}} ELS-specimen __FORCETOC__ ==General remarks== The Anglo-Saxon abbreviation ELS stands for ‘End-Loaded Split’. The ELS-specimen is used to determine the interlaminar fracture toughness of Mode II loading [1]. ==Test specimen shape== Similar to the double cantilever beam (DCB) test (see also: DCB-specimen), a..."

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{{Language_sel|LANG=ger|ARTIKEL=ELS-Prüfkörper}}
{{PSM_Infobox}}
ELS-specimen
__FORCETOC__

==General remarks==

The Anglo-Saxon abbreviation ELS stands for ‘End-Loaded Split’. The ELS-specimen is used to determine the interlaminar fracture toughness of [[Fracture Modes|Mode II loading]] [1].

==Test specimen shape==

Similar to the double cantilever beam (DCB) test (see also: [[DCB-Specimen|DCB-specimen]]), a 50 mm long film is inserted. The dimensions are 170 x 20 mm². For carbon-fibre reinforced polymer (CFRP) laminates, B = 3 mm and glass-fibre reinforced polymers (GFRP) B = 5 mm are used to account for delamination growth in test specimens with different stiffnesses (if the test specimens are too thin, there is a risk of premature [[Fracture|fracture]] in the crack initiation area). CCD cameras (CCD = charged coupled device) are used for visual assessment of [[Crack Propagation|crack growth]].

[[File:els.jpg|450px]]
{|
|- valign="top"
|width="50px"|'''Fig.''':
|width="600px" |End-Loaded Split (ELS) testing according ESIS TC 4
|}

The force is applied uniformly via a load block and the test specimen is loaded at [[Crosshead Speed|crosshead speeds]] of 1 to 5 mm/min. At the same time, the deflection is determined using a suitable measuring system and the [[Specimen Compliance|compliance]] of the test specimen changes due to [[Crack Propagation|crack growth]] in the middle layer.

==Equation for determining the energy release rate==

The [[Energy Release Rate|energy release rate]] is calculated by evaluating the recorded load–deflection diagrams [2].

{|
|-
|width="20px"|
|width="500px" | <math>G_{IIc}=\frac{18 \cdot F^2 \cdot a^2}{B^2 \cdot d^3 \cdot E_f}</math>
|}

mit:
{|
|-
|''F''
|width="15px" |
|load (force)
|-
|''B''
|
|specimen width
|-
|''a''
|
|delaminations length
|-
|''d''
|
|specimen thickness
|-
|''E''f
|
|[[Flexural Modulus|flexural modulus]]
|}

A prerequisite for applying the equation is that the loading and unloading curves match. Otherwise, the correction factors described in the ESIS TC 4 test specification [3] for this test must be determined (non-linearities are caused, for example, by friction effects between the opposing [[Crack|crack]] [[Surface|surfaces]]).

A comprehensive overview of suitable test specimens for [[Fracture Mechanical Testing|fracture mechanics tests]] on [[Plastics|plastics]] and [[Composite Materials Testing|composites]] can be found in [[Specimen for Fracture Mechanics Tests|fracture mechanics test specimens]].

==See also==

* [[Fracture Mechanical Testing|Fracture mechanical testing]]
* [[Specimen for Fracture Mechanics Tests|Specimen for fracture mechanics tests]]
* [[DCB-Specimen|DCB-specimen]]
* [[FRMM-Specimen|FRMM-specimen]]
* [[Energy Release Rate|Energy release rate]]

==References==

{|
|-valign="top"
|[1]
|[[Altstädt, Volker|Altstädt, V.]]: Testing of Composite Materials. In: [[Grellmann,_Wolfgang|Grellmann, W.]], [[Seidler,_Sabine|Seidler, S.]] (Eds.): Polymer Testing. Carl Hanser, Munich (2022) 3rd Edition, pp. 548/549 (ISBN 978-1-56990-806-89; E-Book: ISBN 978-1-56990-807-5; see [[AMK-Library]] under A 22)
|-valign="top"
|[2]
|Wang, H., Vu-Khanh, T.: Use of End-Loaded-Split (ELS) Test to Study Stable Fracture Behaviour of Composites under Mode II Loading. Composite Structure 36 (1996) 71–79; DOI: [https://doi.org/10.1016/S0263-8223(96)00066-9 https://doi.org/10.1016/S0263-8223(96)00066-9]
|-valign="top"
|[3]
|ESIS TC 4 (1995): Protocol for Interlaminar Fracture Testing of Composites (Mode I DCB-ISO 15024 and Mode II ELS-ESIS TC 4)
|}

[[Category:Fracture Mechanics]]
[[Category:Specimen]]

ELS-Specimen - Revision history