# Investigating the Triaxial Mechanical Behaviour of Silicone Rubber Material

## TL;DR

This paper introduces a new model to better understand how silicone rubber behaves under complex mechanical stresses.

## Contribution

A novel constitutive model is proposed to capture the nonlinear triaxial mechanical behavior of silicone rubber.

## Key findings

- The model accurately represents nonlinear large-deformation behavior and sensitivity to biaxiality ratio.
- Simulation results align well with experimental data in deformation patterns and stress–strain curves.
- The model balances parameter count and fitting accuracy better than classical hyperelastic models.

## Abstract

Silicone rubber is extensively used in engineering applications due to its toughness and impact resistance; however, traditional characterisation methods fail to capture its nonlinear deformation characterisation and triaxial mechanical behaviour. To address this, we derived a constitutive model within the framework of continuum mechanics that assumes a condition of near incompressibility and conducted uniaxial, planar, and equibiaxial tension tests to fit the model parameters. Through systematic analysis of triaxial mechanical responses under these three loading modes, we determined the material’s nonlinear large-deformation behaviour and sensitivity to the biaxiality ratio. Comparative analyses with classical hyperelastic models show that the proposed model achieves a good balance between the number of parameters and fitting accuracy. After the parameter-fitting process, we performed finite element simulations of the three loading modes. The simulation results show good agreement with experimental data in terms of deformation patterns and stress–strain curves. This study provides a novel theoretical tool for evaluating the mechanical properties and structural designs of soft materials.