Micromechanically motivated finite-strain phase-field fracture model to investigate damage in crosslinked elastomers

TL;DR

This paper introduces a micromechanically motivated phase-field damage model for crosslinked elastomers, capturing finite-strain viscoelasticity and damage evolution, validated through numerical and experimental comparisons.

Contribution

It develops a novel coupled micromechanical and phase-field model for fracture in elastomers considering chain breakage and viscoelastic effects.

Findings

The model accurately predicts crack initiation and propagation.

Numerical results agree with experimental force-displacement data.

The approach captures softening due to chain breakage.

Abstract

A micromechanically motivated phase-field damage model is proposed to investigate the fracture behaviour in crosslinked polyurethane adhesive. The crosslinked polyurethane adhesive typically show viscoelastic behaviour with geometric nonlinearity. The finite-strain viscoelastic behaviour is modelled using a micromechanical network model considering shorter and longer chain length distribution. The micromechanical viscoelastic network model also consider the softening due to breakage/debonding of the short chains with increase in deformation. The micromechanical model is coupled with the phase-field damage model to investigate the crack initiation and propagation. Critical energy release rate is needed as a material property to solve phase-field equation. The energy release rate is formulated based on the polymer chain network. The numerical investigation is performed using finite element method. The force-displacement curves from the numerical analysis and experiments are compared to validate the proposed material model.