Rock cracking simulation in tension and compression by peridynamics using a novel contact-friction model with a twin mesh and potential functions

Peridynamics (PD) is an effective method for simulating the spontaneous initiation and propagation of tensile cracks in materials. However, it faces great challenges in simulating compression-shear cracking of geomaterials due to the lack of efficient contact-friction models. This paper introduces an original contact-friction model that leverages twin mesh and potential function principles within PD to model rock cracking under tensile and compressive stresses. The contact detection algorithm, based on space segmentation axis-aligned bounding box (AABB) tree data structure, is used to address the significant challenge of highly efficient contact detection in compression and shear problems. In this method, the twin mesh and potential function are utilized to quantify contact detection and contact degree, as well as friction behavior. This is in contrast to the distance and circular contact area model, which lacks physical significance in the classical PD method. As demonstrated by the tests on specimens containing cracks, the proposed model can capture 8 types of secondary fractures, reduce the contact detection error by about 29%–56%, and increase the contact retrieval efficiency by over 1600 times compared to the classic PD models. This significantly enhances the capability of PD to simulate the initiation, expansion, and coalescence of intricate compression-shear cracks.