Speaker
Description
In recent years polymer materials experienced a high amount of interest for their exceptional suitability within lightweight engineering applications. To model their thermomechanical behavior it is crucial to sufficiently capture relaxation effects in mechanical as well as caloric quantities [1]. Possible approaches to handle these effects within a thermodynamically consistent framework are e.g. the introduction of internal variables such as a viscous strain [2] or the extension of the variable space by additional non-equilibrium fluxes such as the heat flux or the viscous stress tensor [3], both of which are related to dissipative effects. In this talk we present a summary of different views onto relaxation equations governing thermo-visco-elastic material behavior [3, 4]. Special focus will be put on the connection to standard rheological models, e.g. the generalized Maxwell model or the Poynting-Thomson model, since they have been proven effective to deliver reasonable results for basic cases under certain assumptions. Additionally, possible approaches for non-linear generalizations extending the validity for a wider spectrum of applications shall be addressed.
REFERENCES
[1] Kehrer, L., Keursten, J., Hirschberg, V. and Böhlke, T., 2023. Dynamic mechanical analysis of PA 6 under hydrothermal influences and viscoelastic material modeling, Journal of Thermoplastic Composite Materials, Volume 36.
[2] Maugin, G. and Muschik, W., 1994. Thermodynamics with Internal Variables. Part II. Applications, Journal of Non-Equilibrium Thermodynamics, Volume 19.
[3] Jou, D., Lebon, G. and Casas-Vázquez, J., 2010. Extended Irreversible Thermodynamics, Springer Netherlands, Dordrecht.
[4] Šilhavý, M., 1997. The Mechanics and Thermodynamics of Continuous Media, Springer Berlin Heidelberg, Heidelberg.
