Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Numerical analysis of dissipation in a large strain thermo-viscoelastic constitutive model
Submission Author:
Péricles Rafael Pavão Carvalho , MA , Brazil
Co-Authors:
Péricles Rafael Pavão Carvalho, Rodolfo Sanches
Presenter: Péricles Rafael Pavão Carvalho
doi://10.26678/ABCM.COBEM2023.COB2023-2181
Abstract
We present a phenomenological large strain thermo-viscoelastic constitutive model, using a total Lagrangian kinematic description based on the multiplicative decomposition of the thermal, elastic and viscous deformation gradients. The model is defined by a Helmholtz free energy, and is thermodynamically-based, meaning that the constitutive equations are derived from the laws of thermodynamics. The thermal component is calculated by an isotropic expansion law in exponential form. The viscoelastic part is represented by Zener’s rheological model. For the elastic part, we apply a neo-Hookean constitutive model. To account for the viscous behaviour, an internal variable model is applied, that is, the viscous deformations are stored as internal variables and updated using the evolution laws, written in terms of the rate of viscous deformation gradient. The equation of heat conduction is derived from the first law of thermodynamics, including the heat generated by viscous dissipation, and the relation between heat fluxes and temperatures is given by Fourier’s law. The constitutive model is applied to a strain-stress example of uniaxial monotonic loading over different strain and stress rates. Graphs such as mechanical dissipation and energy rates over time are presented for each case to characterize the dissipative behaviour of the problem.
Keywords
dissipation, viscoelasticity, thermo-viscoelasticity, large strain, thermo-mechanical
