Modeling and Simulation of the long-term Behavior of Thermoplastics in LS-DYNA

Viscoelasticity respectively the time-dependent and the recovery behavior plays an essential role, especially for polymers. Nowadays, it is becoming increasingly important to be able to make service life predictions and forecasts regarding the long-term behavior of components using simulation models. In this context, constant or cyclic loads are usually the decisive mechanisms for deformation. Moreover, the short-term behavior of plastics is also strongly characterized by viscoelastic phenomena. Even in the case of very short-time high loads on polymer components, the corresponding recovery behavior is of great importance and must be correctly represented in the simulation. Material and simulation models must take this long-term but also the short-term behavior into account for a realistic prediction of the deformation behavior in order to be able to make corresponding estimates of the service life of components, which is often designed for years. For this purpose, this behavior must be characterized in the application-specific framework and considered accordingly in the modeling. This article will present and compare some of the currently available material models that can account for the viscoelastic or time-dependent behavior of polymers, as well as the possibilities and effort required to obtain the material data needed for simulation.