A Hamiltonian particle-finite element method for elastic-plastic impact simulation

A general energy based system model is needed to accurately simulate high velocity impact type situations e.g. space debris and anti-terrorist defense. Obviously, to design a more optimal structure to overcome the effects of these potentially catastrophic events requires accurate models to predict system performance; especially given that testing is extremely difficult and expensive with current capabilities.; General numerical models of hypervelocity impact problems must account for large strain deformation, isochoric rate dependent plasticity, volumetric and deviatoric damage, and complex energy domain coupling as well as perforation and fragmentation. Although Lagrangian finite element techniques are well suited to model the continuum dynamics aspect of such problems, particle models have inherent advantages in representing the equally important non-continuum effects, including general contact-impact and debris transport. Incorporating all these effects into current damage and fragmentation models is difficult, given their limited thermodynamic framework.; An alternative, systematic approach to the model formulation process results in a new hybrid numerical method using particles and finite elements simultaneously but not redundantly to model contact-impact and volumetric deformation while finite elements are employed to represent interparticle tension forces and elastic-plastic deviatoric deformation. A principal computational cost of the present formulation is the need to incorporate both particle-based and element-based kinematics, although nowhere are the prescribed element and particle based computations redundant. More general elastic-plastic constitutive assumptions, alternative finite element interpolations, or additional internal states could be introduced. Expansion of the formulation to include additional internal states is facilitated by the use of a modeling approach based uniformly on Hamiltonian mechanics. The solid dynamics model demonstrates accurate results in example three-dimensional simulations.