Modeling cracks in nonlinear viscoelastic media subjected to thermal loading

Abstract

This thesis study deals with the crack initiation and propagation analyses in nitely deforming viscoelastic media. The main goal of the study is to obtain a methodology for crack propagation analyses in bulk material and interface debonding using Extended Finite Elements (XFEM) and Cohesive Zone Modeling (CZM). Firstly several benchmark analyses were performed using CZM, XFEM and conventional crack propagation method based on J integral and the results were evaluated. Then using an analog rocket motor from literature, stress analyses were performed for bore cracking and debonding under monotonic temperature loading. The results were compared qualitatively and quantitatively with the test results of related studies from literature to verify the model to be used for propagation analyses. Finally, crack propagation was analyzed under cyclic temperature loadings for several initial defect sizes and crack growth was calculated as a function of loading. It is concluded that, XFEM and CZM are e cient and appropriate methods for crack propagation analysis in nonlinear viscoelastic media.