FIB manufactured microstructures with low coefficients of thermal expansion

Abstract

This study presents a novel method to describe the microscale phenomenon of cracks initiation based on sensitivity analysis in laminate fiber-reinforced composites. The failure of fiber-reinforced composite laminates often roots in the microscale phenomenon of fiber/matrix interfacial debonding. The micro-cracking and interfacial debonding in composites are difficult to detect both experimentally and numerically. This paper shows that the sensitivity of the stress response in a transverse ply with respect to individual fiber/matrix interface cohesive properties follows a normal distribution before cracks initiate. The distribution of the sensitivities rapidly deviates from a normal distribution from crack initiation to the formation. Several realistic microstructural representations of a fiber-reinforced composite laminate are simulated to validate the proposed method of detecting crack initiation. This proposed prediction method of crack initiation can be used as a failure risk indicator to increase the reliability of laminates’ designs.