Extracting Crack-tip Field Parameters in Anisotropic Elastic Solids From Full-field Measurements Using Least-squares Method and Conservation Integrals

Abstract

This paper presents parameter-estimation methods developed to determine crack-tip field parameters in anisotropic elastic solids from full-field experimental data. The crack-tip field parameters of interest include not only stress intensity factors but also effective crack-tip positions. Two approaches that are based on least-squares method and conservation integrals were presented. In the approach based on the least-squares method, the Stroh representation of anisotropic elasticity was used to determine the coefficients in the asymptotic expansion of crack-tip fields in anisotropic solids. On the other hand, conservation integrals in fracture mechanics, such as J-integral, M-integral, Interaction integrals, were also used to extract the parameters including the effective crack-tip position. Both approaches were employed to analyze crack-tip displacement fields obtained by using Digital Image Correlation technique during translaminar fracture test of a fiber- reinforced polymer matrix composite. The applicability of homogeneous isotropic plane-elasticity models to translaminar fracture processes in laminated composite materials is also discussed.