Users should refer to the original published version of the material for the full abstract. No warranty is given about the accuracy of the copy. However, users may print, download, or email articles for individual use. Copyright of Continuum Mechanics & Thermodynamics is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission.Nevertheless, application of the standardized ENF procedure to determination of the fracture toughness of laminates exhibiting elastic couplings is still possible, provided assistance of additional data reduction schemes and techniques or numerical analysis. Results revealed that the effect of elastic couplings might influenced on intense bridging phenomena, more extensive fracture process zone and contribution of the mode III in total delamination resistance.
Delamination surfaces of coupled laminates after the ENF tests were investigated by using the scanning electron microscopy. Greater values of the fracture toughness obtained by using the non-standardized methods can be explained by the effect of the fracture process zone which was taken into account in the CBBM calculation scheme.
End notch flexture test crack#
A special displacement gage has been developed for direct measurement of crack shear displacement (CSD) that is the relative shear slip between the upper and lower crack surfaces of the ENF specimen. Results obtained by using the classical data reduction schemes were compared with the compliance-based beam method (CBBM). A stabilized end notched flexure (ENF) test has been proposed for experimental characterization of Mode II interlaminar crack growth. Data analysis of the ENF test was performed by using both the direct beam theory and the corrected beam theory. Determination of crack initiation was supported by the acoustic emission technique. All experiments were performed according to the ASTM D7905 Standard. Influence of elastic coupling phenomena on behavior of laminates subjected to the bending moment as well as on fracture toughness and delamination surfaces after the ENF tests was discussed. In addition, multidirectional laminates with different delamination interfaces were tested. The object of research were carbon/epoxy composite laminates with specific stacking sequences exhibiting the bending–extension and the bending–twisting couplings.
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