Ductile fracture in tube impact problem using a Lode angle dependent failure criterion

Impact problems are an important class of problems usually accompanied by large deformations and sometime fracture of the impacting bodies. In many fields such automotive crashworthiness analysis and design, turbine design, metal forming problems etc. one has to invariably consider the possibility of fracture and study its effect on the component/structure. Fracture in these applications is mostly happens after considerable plastic deformation and is referred to as ductile fracture. A lot of research work has being carried out in the area of ductile fracture under impact loads. Recently, a new coupled elasto-plastic damage model for ballistic applications incorporating effect of Lode angle in the Johnson and Cook failure criterion using a Lode angle dependent function has been proposed. In the present work, this model is employed to study the ductile fracture of tubes impacted against a rigid surface using Abaqus/Explicit through a user input subroutine VUMAT. The effect of Lode angle on the fracture pattern is studied. It is shown that the Lode angle significantly affects the failure pattern. (C) 2019 The Authors. Published by Elsevier B.V.