Ernst Viehböck,
"Practical viscoelastic characterization and numerical modelling of polyamide compounds"
, 2022
Original Titel:
Practical viscoelastic characterization and numerical modelling of polyamide compounds
Sprache des Titels:
Englisch
Original Kurzfassung:
The use of polymeric materials has become more and more popular in highly demanding structural engineering applications. Due to the molecular structure of plastics, most of them show a pronounced intrinsic viscoelasticity. Consequently, engineering with such materials requires not only a deep understanding of the underlying mechanisms, but also the tools to use this knowledge in application. The viscoelastic nature of polymers leads to creep and relaxation processes in the material, which must be considered when designing structural components. To do so, there is a variety of approaches for experimental and computational modelling of creep available. The standard procedure for investigating the creep behaviour of plastics is a very time-consuming and cost-intensive creep experiment. Since creep is a viscoelastic property, it is reasonable to assume that the time-temperature superposition principle (TTSP) could be used to obtain quicker results. In the field of FE modelling, DMA is widely used in combination with the Prony series to describe viscoelasticity. Unfortunately, the results from the DMA cannot directly be used to describe the creep behaviour of such engineering polymers. However, by combining the results from creep and DMA tests, a sufficient description can be achieved. The resulting novel modeling process is less time consuming since the TTSP is applied to creep data. Thereby, the shift factors obtained from the DMA are directly applied to the normalized creep curve, yielding a simple temperature extension for a specific stress level of a regular creep curve. At the current state, the method has some limitations in terms of transferability to non-similar geometries. However, the description and implementation of this non-standard approach is relatively simple and showed highly promising results in the performed benchmark simulations with Abaqus.
Forschungs-