A Composite Material Model for High Strain Rates

For polymer matrix composites subjected to large strain rates, it is important to correctly characterize the nonlinear and strain rate dependent response of polymers. For this purpose, viscoplastic constitutive equations originally implemented for metals have been modified to account for the effects of hydrostatic effects and inelastic strains in polymers. The resultant stress in the composite can then be obtained by using a mixture theory that averages the individual stresses of the polymer and fiber (assumed to be elastic) constituents. The implementation of such analytical models using finite element methods constitutes one of the first objectives of the current effort. A continuum model that combines the individual constituents is defined using mixture theory. Experimental tests will be used to validate the preliminary analytical model and verify its efficiency and applicability for engineering applications.