Despite the remarkable material properties, the thermoplastic components subjected to the stress conditions exhibit considerable dimensional instability. Based on the exact simulation of the creep behavior, the required operating time as well as faultless component function can be achieved. In this context, the development of a suitable material model with a reliable and accurate characterization method is crucial. In order to be able to characterize the long-term creep behavior of thermoplastic materials accurately, the newly developed tensile testing device with optimized measurement conditions is presented. Within the development process, this work deals with the detailed description of testing setup configuration, construction proposal, and the functionality of the user software. Here the functional principle and the optimized design solutions are described in greater detail. Due to the required acceleration of the characterization process, a total of five measuring cells for measuring the long-term creep behavior in the linear and nonlinear deformation region have been constructed. The measuring properties of the designed test devices fulfill the highest test requirements that characterize testing of polymers. This declaration is confirmed by the comprehensive validation process. The repeatability of the creep curves and the comparability of the results measured using different test setups are assumed as evaluation criteria. The accuracy of the testing setups is verified by comparison of the measured creep curves using the developed equipment with the measurements obtained by the commercial machine Q800 (TA Instruments). The experimental part of this work consists of the investigation of the stress-dependent creep behavior of polycarbonate, which is carried out under different constant temperatures, such as 40 °C, 60 °C, 80 °C and 100 °C. The measurement results are evaluated with respect to the time and strain. In the context of the subsequent analysis, a significant influence of crazing on creep behavior could be determined. The stress- and temperature-dependent material behavior is described by the corresponding activation processes. With regard to the surface observations of the stressed tensile specimens, tertiary creep is associated to the isotropic damage concept and successfully fitted. The fitted relationships, which describe the material deformation mechanisms, represent the fundamental basis for the development of the relevant material model. An additional part of this work contains the thermomechanically consistent derivation of the proposed material model. In this context, the fundamentals of continuum mechanics will also be introduced. Furthermore, the material model will be implemented in commercial FEM-Software. It is shown that the model can reproduce the effects observed in the experiment. Simultaneously, the simulation of component example is carried out and discussed here.    «

Despite the remarkable material properties, the thermoplastic components subjected to the stress conditions exhibit considerable dimensional instability. Based on the exact simulation of the creep behavior, the required operating time as well as faultless component function can be achieved. In this context, the development of a suitable material model with a reliable and accurate characterization method is crucial. In order to be able to characterize the long-term creep behavior of thermoplastic...    »