The numerical prediction of material failure based on the material point method.

摘要

A new discrete constitutive model for predicting the initiation of delamination and simulating the evolution of separation for laminated composites is presented and implemented in a numerical code based on the Material Point Method. Analytical solutions under uniaxial stress are derived and include the possibility of load reversal or snap back. For numerical solutions, parameter regimes are chosen to preclude snap back. The numerical examples are constrained to uniaxial loading for simplicity to illustrate this new approach but the theory behind the constitutive model allows for a general failure simulation. The decohesion constitutive model and numerical algorithm can handle general modes of failure. The pure shear and normal modes are treated as the extreme cases of the general mode. The normal failure mode corresponds to an opening mode in the direction normal to the laminates while shear failure consists of a discontinuity in displacement along the surface of the laminate. Numerical calculations provide solutions with small dissipation and show a good match between theoretical and numerical solutions for energy, the peak load, slopes of load-displacement curve and the stress field.