岩石类材料直接拉伸破坏的FDEM数值模拟OA北大核心CSTPCD

The combined finite-discrete element method(FDEM)is widely employed in simulating rock crack propagation,especially in direct tensile simulations for parameter validation.However,simulation results are often influenced by the tensile rate and mesh size.Firstly,the fundamental principles of FDEM was elucidated.Secondly,a direct tensile numerical model was established to investigate the effects of tensile rate,mesh size,and height-to-diameter ratio on failure patterns and mechanical parameters.Finally,recommendations for the appropriate tensile rate and mesh size in direct tensile simulations were provided.The results show that as the tensile rate increases,the tensile strength,degree of failure and peak strain rate of the specimen also increase,while the average elastic modulus decreases.When tensile rates are lower(v≤0.01 m/s),the specimen develops only a single main tensile crack.When the tensile rates are higher,branch cracks appear on the upper side of the main tensile crack.The mesh size has a minimal impact on tensile strength,peak strain rate and average elastic modulus,but it significantly affects the failure pattern and degree of failure.With the increase of height-to-diameter ratio,the tensile strength,degree of failure and peak strain rate of the specimen increase,whereas the average elastic modulus shows an opposite trend.Moreover,the height-to-diameter ratio significantly influences the degree of failure.It is recommended to use a tensile rate of 0.01 m/s and limit the mesh size to within 1.5 mm in direct tensile simulations.