Abstract: The simulation technique of materials’ failure has a great influence on the validity of the results. Based on the knowledge of materials’ failure criterion, two easily-overlooked issues in numerical simulation are put forward, which include elements’ erosion and inner contact after erosion during the numerical computation. With the background of cylindrical specimen’s failure test under compression loads and rock tunnel’s collapse test, the influence of the two issues on materials’ fracture are evaluated. Theoretical analysis and numerical computation indicate that, by defining constrained node set with failure and inner contact condition, the failure problem of materials and media can be properly simulated, such as the rock tunnel’s collapse, etc, the erosion algorithm for severe distorted elements has obvious imperfection.

Key words: numerical simulation, failure, erosion, inner contact