USE OF A RATE-DEPENDENT CONTINUUM DAMAGE MODEL TO DESCRIBE STRAIN-SOFTENING IN LAMINATED COMPOSITES

A continuum damage model developed to describe the rate-dependent dyna mic response of laminated polymer composites is investigated for its b ehavior during strain-softening. The formulation is shown to lead to m athematically well-posed wave propagation problems as well as to uniqu e and stable solutions. Numerical simulations of unidimensional wave-p ropagation in the through-thickness direction of a transversely isotro pic laminate are performed. For a realistic range of damage propagatio n time constants the results are shown to be mesh insensitive and conv ergence to a finite amount of dissipated energy is obtained; two issue s of concern in modeling dynamically strain-softening solids. Thus the model is validated with respect to strain-softening regimes.