Coupling the theory of viscoelasticity and continuum damage mechanics to model the time dependent behavior of fiber reinforced plastics and particulate composites

Reinforced plastics show a strong time dependent behavior which is due to the time dependent behavior of the matrix whereas their reinforcing fibers or particles are usually show time independent behavior. The aim of the present research project was to model this behavior by the theory of viscoelasticity and non-linear effects within the theory of Continuum Damage Mechanics. Fiber reinforced plastics reinforced both by swirl-mats used as plates and by cut fibers used as pipes were studied. For these materials the long time behavior was modeled (e.g. creep till failure). The particulate composites investigated were solid propellant and asphalt concrete; on these the influence of the loading rate was modeled. Constitutive equations were developed and implemented in the FEM program ABAQUS. The FEM results were compared to analytical and experimental results.