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

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