Removing mesh bias in mixed‐mode cohesive fracture simulation with stress recovery and domain integral

• Published in: International journal for numerical methods in engineering Vol. 120; no. 9; pp. 1047 - 1070
• Main Authors: Choi, Habeun, Park, Kyoungsoo
• Format: Journal Article
• Language: English
• Published: Bognor Regis Wiley Subscription Services, Inc 30.11.2019
• Subjects: Axial stress; Bias; Cohesion; Computer simulation; domain integral; element split; extrinsic cohesive zone model; Finite element method; Integrals; mesh bias; mixed‐mode fracture; Recovery; Representations; Stiffness matrix; Strain energy release rate; Stress distribution; stress recovery
• ISSN: 0029-5981; 1097-0207
• DOI: 10.1002/nme.6170

Summary To remove mesh bias and provide an accurate crack path representation in mixed‐mode investigation, a novel stress recovery technique is proposed in conjunction with a domain integral and element splits. Based on a domain integral and stress recovery technique, a maximum strain energy release rate is estimated to determine a crack path direction. Then, for a given crack path direction, continuum elements are split, and a cohesive surface element is adaptively inserted. One notes that the proposed stress recovery technique provides a more accurate stress field than a standard stress evaluation procedure. The proposed computational framework is verified and validated by solving mode‐I and mixed‐mode examples. Computational results demonstrate that the domain integral with the stress recovery accurately evaluates a crack path, even with a lower‐quality mesh and under a biaxial stress state. Furthermore, the cohesive surface element approach, with the element split in conjunction with the stress recovery and the domain integral, predicts mixed‐mode fracture behaviors while removing mesh bias in the crack path representation. Additionally, the condition numbers of stiffness matrices are within the same order of magnitude during cohesive fracture simulation.