Simulation of the Long Term Behavior of Polymers on the Basis of Short Term Data

Abstract

The mechanical long term behavior of polymers is usually determined by long term creep experiments up to 10.000 h which are very time and cost consuming. Therefore these data are often not available for the engineer. But even if long term data is available FEA-tools used in industrial practice usually can not sufficiently represent the nonlinear time, temperature and load-dependency of the mechanical long term behaviour. Hence the dimensioning of polymer parts is still a rather difficult engineering task. As a consequence of this, additional time consuming and expensive component tests in combination with several iterations are often necessary to design a polymer part for long term behaviour.

This paper develops a method for the modeling of the load and temperature-dependent mechanical behaviour of polymers over a wide time, load and temperature range by means of finite element analysis. The method includes a material model as well as the determination of material parameters to calibrate the model. As a special feature of this method the model is calibrated by using creep data generated from short term experiments. The procedure improves the simulation of the long term behaviour of plastic-components and reduces the experimental effort significantly. The simulation results are finally validated by creep experiments performed on an example part.