A simple implementation of localizing gradient damage model in Abaqus

Abstract

With the localizing gradient enhancement, a damage model for quasi-brittle materials is able to achieve regularized softening responses, with localized damage profiles corresponding to the development of macroscopic cracks, to resolve the numerical spurious effects induced by the conventional gradient enhancement. The typical implementation strategy for a gradient enhanced model is to solve the system of governing equations simultaneously. Focusing on the finite element (FE) package Abaqus, a user element subroutine is required to define the finite elements with additional degrees of freedom for the nonlocal field. Moreover, with user elements, additional effort is required to visualize the numerical results. To an inexperienced engineer/researcher, these requirements can be challenging. In this paper, a simple implementation of the localizing gradient damage model is elaborated. By utilizing the in-built coupled thermo-mechanical elements in Abaqus, the user only needs to define the material constitutive laws, as well as the sensitivity terms with respect to the field variables. Post-processing of results can be done directly in Abaqus. The applicability and ease of implementation are demonstrated via several examples, including those that utilize the Abaqus features of element deletion, contact between surfaces, as well as the incorporation of cohesive elements. Sample files can be downloaded from https://github.com/leonghien/Localizing-Gradient-Damage-with-UMAT-UMATHT

A simple and efficient implementation of localizing gradient damage method in COMSOL for fracture simulation

“…Notable works on the computer implementation of discrete methods include extended FEM (XFEM) (Giner et al, 2009;Shi et al, 2010;Rokhi and Shariati, 2013;Sutula et al, 2018;Ding et al, 2020;Jafari et al, 2022) and cohesive zone method (Park and Paulino, 2012). For smeared methods, the popular works on computer implementation include the phase field method (Msekh et al, 2015;Molnar and Gravouil, 2017;Zhou et al, 2018;Fang et al, 2019;Molnar et al, 2020;Chen and Wu, 2022;Rahaman, 2022), peridynamics (Huang et al, 2019;Bie et al, 2020, Jenabidehkordi andRabczuk, 2022) and gradient damage method (Seupel et al, 2018;Sarkar et al, 2019a, Sarkar et al, 2019b, Sarkar et al, 2022bZhang et al, 2022).…”