An embedded cohesive crack model for finite element analysis of brickwork masonry fracture

Abstract

This paper presents a numerical procedure for fracture of brickwork masonry based on the strong discontinuity approach. The model is an extension of the cohesive model prepared by the authors for concrete, and takes into account the anisotropy of the material. A simple central-force model is used for the stress versus crack opening curve. The additional degrees of freedom defining the crack opening are determined at the crack level, thus avoiding the need of performing a static condensation at the element level. The need for a tracking algorithm is avoided by using a consistent procedure for the selection of the separated nodes. Such a model is then implemented into a commercial code by means of a user subroutine, consequently being contrasted with experimental results. Fracture properties of masonry are independently measured for two directions on the composed masonry, and then input in the numerical model. This numerical procedure accurately predicts the experimental mixed-mode fracture records for different orientations of the brick layers on masonry panels.

Estudio de la fisuración de paneles sándwich de yeso laminado y alma de lana de roca

“…El valor umbral que limita la adaptabilidad está relacionado con los parámetros de ablandamiento del material. En este trabajo se adopta un valor de 0,1-0,2 G F /f t , empleado satisfactoriamente en trabajos previos (5,6,18). Superado este umbral se considera la grieta consolidada.…”

“…Threshold values of the crack adaptability must be related to the softening properties of the material. In this paper a value of 0.1-0.2 G F /f t is adopted, one that has been used in previous works (5,6,18). Once the threshold is reached, the crack direction is consolidated.…”

“…The model is based on the strong discontinuity approach (17). The procedure has been developed for the simulation of mixed-mode fracture of concrete and mortar (18) and later extended to anisotropic materials such as brickwork masonry (6).…”

An embedded cohesive crack model for finite element analysis of quasi-brittle materials

“…As in previous works [41][42][43][44], based on this approach, the deformation is localised on a line using the concept of the cohesive crack, and the discrete constitutive relation for mixed mode fracture is a cohesive crack with a central-force model. The model avoids crack tracking [45,60] or exclusion zones for crack growing.…”

“…For this purpose the crack is numerically implemented as a discontinuity embedded in a classical FE. The modelling is mainly based on the authors' proposal for concrete [41][42][43] and masonry [44].…”