Investigation of mesh dependency issues in the simulation of crack propagation in quasi‐brittle materials by using a diffuse interface modeling approach

Abstract

This work proposes an efficient cohesive finite element modeling approach based on a diffuse interelement interface strategy to reproduce the fracture behavior of quasi‐brittle materials under general loading conditions. The proposed model involves zero‐thickness interface elements, whose strength and toughness properties are spatially randomized, thus avoiding the well‐known nonuniqueness issues that can affect the stability of the associated numerical computations, which potentially lead to physically meaningless predictions of the fracture behavior. The reliability of the proposed refined fracture approach is assessed by performing several numerical simulations of the direct tensile test on various quasi‐brittle specimens. Results show that a proper calibration of the cohesive properties of the diffuse embedded interfaces is fundamental to ensure the desired numerical accuracy and stability properties. Besides, comparisons with experimental and numerical data found in the literature are used to fully validate the proposed approach.

Multiscale failure analysis of fiber-reinforced composite structures via a hybrid cohesive/volumetric nonlinear homogenization strategy

“…1a). This solid is damageable, so that fracture is represented via a Diffuse Interface Modeling (DIM) approach, according to which cohesive interfaces, denoted by coh M Γ , are placed along all the internal mesh boundaries (for additional details see, for instance, [18][19][20][21][22][23]). Given the periodic nature of the considered microstructure, a suitable Repeating Unit Cell (RUC) is defined to microscopically derive the bulk and interface constitutive relations, which are valid before and after strain localization, respectively (see Figs.…”

Microgeometrical design of lightweight bioinspired nacre-like composite materials for wave attenuation tuning

“…Due to recent advancements in additive manufacturing, numerous researchers are exploring the high potential for designing nacre-like bioinspired materials with advanced properties finding applications in a wide range of engineering fields [6][7][8]. Due to their complex microstructure, composite materials are heterogeneous media that are susceptible to various nonlinear phenomena, especially if subjected to large deformation, such as instabilities at the microscopic and macroscopic scale [9] or damage mechanisms involving the microscopic scale such as matrix cracking or debonding of the fiber-matrix interfaces [10][11][12][13]. It is widely known that there is a strict correlation between these microscopic mechanisms and macroscopic fracture phenomena such as delamination, interfacial debonding, and multiple crack propagation which are generally considered the most frequent precursors of damage in microstructured composites [14][15][16][17].…”

A moving cohesive interface model for brittle fracture propagation

“…The discrete crack models are often employed to simulate the interfacial crack in adhesive-bonded ductile sheets by using different phenomenological-type traction-separation laws, to describe the mechanical behavior of the cohesive forces acting along a predefined crack path [5,6]. Recently, to predict unknown crack paths, a diffuse interface model has been introduced and employed to investigate the damage phenomena in quasi-brittle materials and masonry structures [7,8]. However, such a model suffers from the well-known artificial compliance effect and requires a suitable calibration of the cohesive properties of the embedded interfaces to ensure the desired numerical accuracy [9,10].…”