A plasticity concrete material model for DYNA3D

Lagrangian finite element codes with explicit time integration are extensively used for the analysis of structures subjected to explosive loading. Within these codes, numerous material models have been implemented. However, the development of a realistic but efficient concrete material model has proven complex and challenging. The plasticity concrete material model in the Lagrangian finite element code DYNA3D was assessed and enhanced. The main modifications include the implementation of a third, independent yield failure surface; removal of the tensile cutoff and extension of the plasticity model in tension; shift of the pressure cutoff; implementation of a three invariant formulation for the failure surfaces; determination of the triaxial extension to triaxial compression ratio as a function of pressure; shear modulus correction; and implementation of a radial path strain rate enhancement. These modifications insure that the response follows experimental observations for standard uniaxial, biaxial and triaxial tests in both tension and compression, as shown via single element analyses. The radial path strain rate enhancement insures constant enhancement for all those tests. As a full scale example, a standard dividing wall subjected to a blast load is analyzed and the effects of the modifications assessed.