Fatigue Life Prediction of Laminated CFRP Based on Micro Stress Analysis of Resin

Abstract

A versatile methodology for fatigue life prediction is indispensable for establishing fatigue strength design methods that guarantee the long-term reliability of carbon-fiber-reinforced plastics (CFRP), In this study, interfacial normal stress (INS) was determined for unidirectional CFRP specimens. The obtained INS was used for predicting the fatigue life of laminated CFRP specimens, assuming that the fatigue life of CFRP is governed by the microstructural stress in the resin. Fatigue tests were conducted on three types of laminated specimens with stacking sequences of [0/30/－30/90]s, [0/45/－45/90]s, and [0/60/－60/90]s. The INS in the resin part of the microstructure was precisely evaluated by two-scale stress analysis, focusing on two spatial scales: microstructure and macrostructure. The sequential fatigue ruptures in the laminae of the specimen have been successfully predicted using INS based on the results of the fatigue test for the pure resin.