Publications / SAND Report

Lagrangian Material Tracers (LMT) for Simulating Material Damage in ALEGRA

Sanchez, Jason J.; Luchini, Christopher B.; Strack, Otto E.

A method for providing non-diffuse transport of material quantities in arbitrary Lagrangian- Eulerian (ALE) dynamic solid mechanics computations is presented. ALE computations are highly desirable for simulating dynamic problems that incorporate multiple materials and large deformations. Despite the advantages of using ALE for such problems, the method is associ- ated with diffusion of material quantities due to the advection transport step of the computa- tional cycle. This drawback poses great difficulty for applications of material failure for which discrete features are important, but are smeared out as a result of the diffusive advection op- eration. The focus of this work is an ALE method that incorporates transport of variables on discrete, massless points that move with the velocity field, referred to as Lagrangian material tracers (LMT), and consequently prevents diffusion of certain material quantities of interest. A detailed description of the algorithm is provided along with discussion of its computational aspects. Simulation results include a simple proof of concept, verification using a manufac- tured solution, and fragmentation of a uniformly loaded thin ring that clearly demonstrates the improvement offered by the ALE LMT method.