Modelling and Computation of Silicone Rubber Deformation Adapting Neo-Hookean Constitutive Equation

Abstract

In skin research area particularly on the development of skin substitutes or synthetic skin, the determination of the mechanical properties of skin and hyperelastic materials has always been challenging but yet interesting to be explored. To date there is no appropriate model ideally used to denote the skin. Known as a potential skin substitute material, Silicone rubber behaviour is also difficult to characterise. Therefore, this study for the first time attempts to assess the deformation behaviour of silicone rubber materials via the experimental approach, along with modelling and computation adapting hyperelastic constitutive model (i.e. neo-Hookean). Initially, uniaxial tensile test is performed to measure the stress-stretch response silicone rubber based materials employing ASTM D412 testing standards. All samples behave in a similar way and this data is acceptable as it possesses a slight percentage of variance which is less than 5% showing the consistency of the experiment performed. Neo- Hookean hyperelastic constitutive equation has been adopted to represent the materials behaviour in terms of materials constant. The experimental stress-stretch data were used as an input in order to analytically compute the materials constant of silicone rubber. Engineering stress-stretch (δE-λ) curve plot from analytical results has been fitted to the experimental data curve plot. Results indicate that the neo-Hookean model is capable to provide reliable data in describing the deformation behaviour of Silicone Rubber based materials. The neo- Hookean material constant (C1) value is found to be 1.3078 MPa. Therefore it can be concluded that neo-Hookean constitutive model is suitable in representing the deformation behaviour of silicone rubber materials. Also the current study has contributed significantly to the knowledge of potential skin substitute materials especially for silicone rubber materials in modelling and computing its deformation behaviour.