Crack Growth and Residual Strength Prediction of Thin- Walled Aluminum Structures Using XSHELL

摘要

This study is focused on the development and demonstration of the capability of the XFEM shell toolkit for Abaqus (XSHELL) to characterize the fracture pattern and load-deflection of a thin-walled metallic structure subjected to dynamic loading. The mesh independent crack description and fracture energy dissipation characterization are achieved in XSHELL through the implementation of two overlay elements with an embedded cohesive interaction along an arbitrary crack segment without being in conformation to the existing finite element mesh. Both an automatic element reconstruction and a mass allocation module are implemented in XSHELL for kinematic representation of a cracked shell along with its nodal mass redistribution. To enhance the computational efficiency, a Belytschko-Lin-Tsay shell element is implemented with a one point quadrature scheme and an hourglass control in an explicit time integration scheme. Both a critical cumulative plastic strain based fracture criterion and a material instability criterion are implemented in XSHELL to predict the crack initiation while its subsequent growth direction is driven by either a maximum principal stress or strain criterion. The modeling capability and solution fidelity of the XSHELL methodology is verified for crack growth and load deflection prediction of both unstiffened and stiffened steel panels subjected to indentation.