Stress wave propagation in composite materials

The linear constitutive relations and the failure criteria of composite materials made of<br />thermoviscoelastic solids are presented. The post-failure material behavior is proposed and the dynamic<br />finite element equations are formulated. However, a nonlinear term is kept in the energy equation because<br />it represents the effect of the second law of thermodynamics. A general purpose nonlinear three-dimensional<br />dynamic finite element program COMPASS is upgraded and employed in this work to investigate the<br />interdependence among stress wave propagation, stress concentration, failure progression and temperature<br />elevation in composite materials. The consequence of truthfully incorporating the second law of thermodynamics is<br />clearly observed: it will always cause temperature rise if there exists a dynamic mechanical process.