A simplified methodology to identify material parameters of a hyperelasto-visco-hysteresis model: application to a fluoro-elastomer

Abstract

This paper presents a method to identify material parameters of a Hyperelasto-Visco-Hysteresis (HVH) model and its application for the simulation of a fluoroelastomer behaviour. This 3D-phenomenological model is based on the additive decomposition of three stress components. Each of these constitutive stresses is related to a physical phenomenon that occurs during mechanical loading: a hyperelastic equilibrium stress response, an irreversible pure hysteresis stress contribution and a rate-dependent viscoelastic stress behaviour.In order to independently identify these parts of the model, an experimental campaign, including multi-step relaxation in traction and compression tests and simple relaxation in tension and compression tests, is used. The hysteretic and hyperelastic contributions are identified considering only the state at the end of the relaxation periods of the multi-step relaxation tests. The viscoelastic response is analytically calculated with the simple relaxation test. As an advantage, the developed identification scheme gives the possibility to discriminate all the stress components of the model. Finally, the numerical simulation of a seal in relaxation is carried out to verify the capability of the proposed HVH model by reproducing the mechanical response of the studied material.

Experimental and numerical study on the temperature-dependent behavior of a fluoro-elastomer

“…Similar tests were performed at room temperature by Vandenbroucke et al (2010) and Laurent et al (2011). An Instron testing machine was used for this purpose with a temperature controlled chamber.…”

“…In this section, the structure of the HVH model previously presented in the studies by Vandenbroucke et al (2010) and Laurent et al (2011) will be briefly recalled. This phenomenological 3D model was implemented in a finite element software program called Herezh++ (2005).…”

“…After several numerical tests and based on previous studies at room temperature (Laurent et al 2011), it turned out that two branches of the Maxwell's model suffice to well describe the viscous behavior during the time taken by the tests used during the identification procedure, which need two stiffnesses E 1 , E 2 and two viscosities η 1 and η 2 to be defined.…”

“…The HVH model, written in a stress decomposition form, makes it easy to identify the material parameters based on the multi-step relaxation test data, as previously described in Laurent et al (2011). The viscous stress σ v , hyperelastic stress σ e and hysteretic stress σ h components are presented in Figs.…”

“…The HVH model has been successfully applied to this rubber at room temperature (Vandenbroucke et al 2010). The procedure originally used to identify the material parameters, which was presented by Laurent et al (2011), was adapted here in order to identify these parameters as a function of the temperature. Special attention was paid to the temperature-dependency of the viscous, hyperelastic and hysteresis parameters.…”