Investigating an Inverse Finite Element Approach for Characterising Soft Materials

ABSTRACT Soft materials, such as soft biological tissue and silicone rubber, are non-linear materials which require the classical uniaxial biaxial tensile testing methods for characterisation. Unfortunately, in special cases, tissue, samples smaller than 10 mm χ size these produce unwanted stress strain gradients due to fastening techniques associated with methods. Micro-indentation is proposed an alternative method characterising materials. Using inverse Finite Element (FE) analysis a known Mooney-Rivlin three parameter material model, six different micro-indentation tests were proposed. A theoretical approach was used determine indentation test best characterised sample, by using two FE models. The results showed that microindentation capable of ideal conditions cylindrical indenter applied diagonal orientation over method. Finally, it observed model can either match displacements smallest objective function or vs. stretch curve be matched 99 % whole range but not both simultaneously. Additional keywords: Inverse Elements analysis, Micro-indentation, Gradient optimisation, hyper-elastic model.