Cryogenic interface strength testing method for carbon fiber composite materials based on crack propagation representative volume model
QIAN Wenxin
GAO Weijian
ZHU Bin
YIN Bo
NIU Yinjie
ZHANG Xiaowen
Abstract：[Objective]To address the challenge of directly and accurately measuring the interfacial strength of carbon fiber composites in cryogenic environments such as liquid hydrogen,an indirect testing method based on inverse identification of interfacial shear strength through crack propagation behavior was proposed,aiming to support the strength design and reliability assessment of cryogenic composite structures.[Methods]Firstly,a representative volume element model for crack propagation was established,characterizing the relationship of energy release rate among the fiber,matrix,and interface.Secondly,longitudinal tensile tests of the T700/TDE-85M composite unidirectional laminates were conducted at different temperatures(from-196℃to 25℃)to obtain fracture surface morphologies.Then,the occurrence probabilities of crack propagation paths(including deflection,penetration,and their combination)were statistically analyzed.Finally,the interfacial shear strength was inversely identified based on the aforementioned model and test data.[Results]The research demonstrates that the interfacial shear strength measured by this method within the temperature range of-196℃to 25℃shows errors within±10%compared to results from the single-fiber pull-out method,verifying the model's validity.Concurrently,it was found that the interfacial strength decreases with decreasing temperature,and cracks are more prone to interface deflection at low temperatures.
Keywords：Carbon fiber composite materialInterface strengthCrack extensionCryogenic testRepresentative volume model
Publication Date：2026-05-31
Online Publishing Date：2026-09-12(First online date of this platform, not the publication date of the document)
Pages：7( 90-96 )