A Mechanism of Failure in Shear Bands

TL;DR

This paper investigates the failure mechanism within shear bands using dilatant plasticity simulations, revealing how softening and void dynamics lead to loss of load capacity, aligning with observed fracture features.

Contribution

It introduces a detailed simulation-based mechanism explaining shear band failure, emphasizing the role of void behavior and softening without volume increase.

Findings

Material softens within shear bands without void volume increase

Failure is driven by softening dependent on shear band width and void spacing

Results align with experimental features like surface roughness and porosity

Abstract

We have carried out dilatant plasticity simulations to investigate the process of failure inside a shear band. The constitutive model accounts for possibly inhomogeneous flow within the band, void rotation and void elongation. We found that the material in the band may soften with no increase in the void volume fraction. For a given matrix hardening capacity, the rate of softening was found to depend strongly on the ratio of shear band width to in-plane void spacing. The emergent softening led to complete loss of load bearing capacity thereby providing a physical mechanism of failure in shear bands. The mechanism is consistent with essential features of shear-fractured specimens in terms of surface roughness, porosity and dimple shape.