Instabilities in elastomers and soft tissues

TL;DR

This paper compares different instability phenomena in elastomers and soft tissues, revealing that strain-hardening does not always stabilize soft tissues and that stability depends on the specific loading geometry.

Contribution

It provides a comparative analysis of instability behaviors in hyperelastic materials, highlighting differences between elastomers and soft tissues under various loadings.

Findings

Soft tissues can be less stable than elastomers in certain geometries.

Strain-hardening does not universally stabilize soft tissues.

Instability outcomes depend on the specific loading configuration.

Abstract

Biological soft tissues exhibit elastic properties which can be dramatically different from rubber-type materials (elastomers). To gain a better understanding of the role of constitutive relationships in determining material responses under loads we compare three different types of instabilities (two in compression, one in extension) in hyperelasticity for various forms of strain energy functions typically used for elastomers and for soft tissues. Surprisingly, we find that the strain-hardening property of soft tissues does not always stabilize the material. In particular we show that the stability analyses for a compressed half-space and for a compressed spherical thick shell can lead to opposite conclusions: a soft tissue material is more stable than an elastomer in the former case and less stable in the latter case.