Numerical Studies of Tension Models: Instantaneous Fracture, Plastic Failure, Rate-Dependent Damage Accumulation

摘要

As part of a continuing study of tension models for ground shock calculations, two rate-independent models (instantaneous fracture and plastic failure) are re-examined. Neither model combines the two desired traits of stability-uniqueness and physical realism. Instead, a modified rate-dependent model is proposed for brittle tensile failure in ground shock calculations. It is based on the ductile damage accumulation equations advanced at SRI and Sandia, but in simplified, fully incremental form. Preliminary uniaxial strain calculations show the model to give physically realistic results, close to the predictions of the more complicated rate-dependent model BFRACT. Further testing of the model for more realistic two dimensional problems and an analysis of cost versus benefit is in progress.