A unified variational framework for phase-field fracture and third-medium contact in finite deformation hyperelasticity

TL;DR

This paper introduces a unified variational framework that models phase-field fracture and third-medium contact in finite deformation hyperelasticity, enabling simulation of complex contact and fracture interactions without explicit interface tracking.

Contribution

It develops a novel regularization-based approach that integrates crack and contact modeling within a single variational framework, simplifying numerical implementation.

Findings

Successfully simulates contact-induced stress concentration and crack propagation.

Reproduces secondary crushing fracture zones near contact regions.

Demonstrates the framework's effectiveness through 2D and 3D validation tests.

Abstract

This paper presents a unified variational framework that integrates phase-field fracture (PFF) and third-medium contact (TMC) within finite deformation hyperelasticity. The key idea is that both crack and contact are treated through regularization: the sharp crack topology is regularized into a diffuse damage field, while the discrete contact interface is regularized by a compliant fictitious medium with auxiliary fields. This strategy eliminates the need for explicit contact detection or crack tracking algorithms. The framework is validated through two-dimensional three-point bending and three-dimensional Brazilian disk test simulations, demonstrating the interplay between contact-induced stress concentration and crack nucleation/propagation. In particular, the Brazilian disk simulation naturally reproduces secondary crushing-type fracture zones near the contact regions -- a phenomenon consistently observed in experiments yet inaccessible to simplified loading models. These results pave the way for predictive simulation of coupled contact-fracture phenomena without recourse to explicit interface tracking.