Development of the modified V-notched rail shear test for carbon fiber reinforced composites with multi-scale simulation method considering microscopic failure points

초록

In this study, a modified V-notched rail shear test was developed to evaluate the shear properties of unidirectional and plain-woven carbon fiber reinforced plastics (CFRPs) under pure shear conditions. The test apparatus was specifically designed to address issues of in-plane and out-of-plane rotation in specimens, which are commonly encountered in conventional V-notched rail shear test. Experimental results obtained from the modified V-notched rail shear test were compared with those from three conventional ASTM standard shear tests (the ±45° tensile test, the Iosipescu shear test, and the conventional V-notched rail shear test). Strain distribution on each test specimen was analyzed using digital image correlation to verify the uniformity of the shear strain state. To further validate the modified V-notched rail shear test, an advanced multi-scale finite element analysis model was developed. Unlike traditional approaches, where the failure region was fixed to a single point in the micro-scale, the advanced model identified multiple failure regions through micro-scale analysis. These multiple regions were then incorporated into the macro-scale analysis, resulting in a more accurate representation of damage progression and overall material behavior. By providing precise and reliable shear property measurements, the modified V-notched rail shear test establishes a robust method for CFRP characterization with broad applicability in research and industry.

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