Velocity mode transition of dynamic crack propagation in hyperviscoelastic materials: A continuum model study

Atsushi Kubo,Yoshitaka Umeno

doi:10.1038/srep42305

Abstract

Experiments of crack propagation in rubbers have shown that a discontinuous jump of crack propagation velocity can occur as energy release rate increases, which is known as the “mode transition” phenomenon. Although it is believed that the mode transition is strongly related to the mechanical properties, the nature of the mode transition had not been revealed. In this study, dynamic crack propagation on an elastomer was investigated using the finite element method (FEM) with a hyperviscoelastic material model. A series of pure shear test was carried out numerically with FEM simulations and crack velocities were measured under various values of tensile strain. As a result, our FEM simulations successfully reproduced the mode transition. The success of realising the mode transition phenomenon by a simple FEM model, which was achieved for the first time ever, helped to explain that the phenomenon occurs owing to a characteristic non-monotonic temporal development of principal stress near the crack tip.

Highlights

Rubbers, or elastomers, have exotic mechanical properties, such as entropic elasticity, viscosity and incompressibility
No numerical simulation has successfully explained or reproduced the mode transition phenomenon far while some simulations have been performed for the dynamic crack propagation in rubber materials[12]
We aim at revealing the nature of the mode transition phenomenon by performing numerical simulation based on the finite element method (FEM)

Summary

Introduction

Elastomers, have exotic mechanical properties, such as entropic elasticity, viscosity and incompressibility. The mode transition phenomenon is industrially important because it is empirically known that the property of the mode transition is related to lifetime of rubber products; i.e., the higher the transition energy (energy release rate at the mode transition) becomes, the higher durability the rubber has There is another kind of transition of the crack propagation in rubber materials that occurs at the vicinity of the sound speed (subsonic-supersonic transition) and has been investigated intensively[16,19,20,21,22]. No numerical simulation has successfully explained or reproduced the mode transition phenomenon far while some simulations have been performed for the dynamic crack propagation in rubber materials[12] It is unknown what relationship exists between the transition energy and the mechanical properties. We discuss the relationship between the mode transition phenomenon and the mechanical response at the crack tip

Methods

Results

Conclusion