Rajasekar Gopalsamy | Searcharxiv

arXiv2026

Dynamic brittle fracture using Lip-field approach in an explicit dynamics context

This paper aims to investigate the dynamic response of a material body undergoing fracture subjected to high strain rate loading conditions such as impact or explosion. In particular, our focus is limited to softening elastic damage models using Lip-field regularization. The Lip-field approach is a new technique to introduce length scale into the softening damage models. It was first presented for the quasi-static case and then extended to a one-dimensional dynamic case. This paper extends the application of the Lip-field approach to dynamic fracture in two-dimensional cases. Lip-field approach is a variational approach, in which the potential to be minimized is a non-regularized one. A potential without regularization can result in spurious strain localization, but the Lip-field approach resolves this issue by imposing Lipschitz constraints on the damage field. Our focus is limited to utilizing an explicit staggered scheme to determine the displacement and damage fields. Numerical studies are conducted for two-dimensional cases to assess the dynamic behavior of the proposed model.

cs.CE↗

arXiv2023

Variational Approach to Viscoelastic Fracture : Comparison of a phase-field and of a lip-field approach

Fracture of viscoelastic materials is considered to be a complex phenomenon due to their highly rate sensitive behavior. In this context, we are interested in the quasi-static response of a viscoelastic solid subjected to damage. This paper outlines a new incremental variational based approach and its computational implementation to model damage in viscoelastic solids. The variational formalism allows us to embed the local constitutive equations into a global incremental potential, the minimization of which provides the solution to the mechanical problem. Softening damage models in their local form are known to result in spurious mesh-sensitive results, and hence non-locality (or regularization) has to be introduced to preserve the mathematical relevance of the problem. In the present paper, we consider two different regularization techniques for the viscoelastic damage model : a particular phase-field and a lip-field approach. The model parameters are calibrated to obtain some equivalence between both these approaches. Numerical results are then presented for the bidimensional case and both these approaches compare well. Numerical results also demonstrate the ability of the model to qualitatively represent the typical rate-dependent behaviour of the viscoelastic materials. Besides, the novelty of the present work lies in the use of lip-field approach for the first time in a viscoelastic context.

cs.CE↗