An adaptive cracking particle method providing explicit and accurate description of 3D crack surfaces

• Published in: International journal for numerical methods in engineering 2018-06, Vol.114 (12), p.1291-1309
• Main Authors: Ai, Weilong, Augarde, Charles E.
• Format: Article
• Language: English
• Subjects: 3D cracks; adaptive; Crack propagation; cracking particles; Finite element method; fracture; Fracture mechanics; meshless; Meshless methods; Particle methods (mathematics); Segments
• ISSN: 0029-5981; 1097-0207
• DOI: 10.1002/nme.5786

Summary Cracks in 3‐dimensions (3D) have arbitrary shapes and therefore present difficulties for numerical modelling. A novel adaptive cracking particle method with explicit and accurate description of 3D cracks is described in this paper. In this meshless method, crack surfaces are described by a set of discontinuous segments, which are associated with particles. This group of particles are assumed all to be “cracked” and split into 2 subparticles with modified support domains. Compared to the original method where the spherical supports at particles are equally divided, the proposed method makes use of nonplanar segments to account for changes in crack face direction. The orientations of those segments and the angular changes of cracks during crack propagation steps are recorded using triangular meshes. Supports of weight functions are modified according to those changes so that quasi‐continuous crack surfaces can be obtained, avoiding the spurious cracking seen in earlier cracking particle methods. An adaptive approach in 3D is then introduced to capture stress gradients around crack fronts. Several 3D crack problems with reference results have been tested to validate the proposed method with good agreement being achieved using the new method, showing it to be potentially a significant advance for 3D fracture prediction problems.