https://orbilu.uni.lu/bitstream/10993/28037/1/1-s2.0-S0045782516304832-main.pdf

Isogeometric boundary element methods for three dimensional static fracture and fatigue crack growth

Decomposition of the mixed-mode J-integral—revisited

Three-dimensional finite elements of steel bolted connections

A novel computational method for simulating fatigue-driven mixed-mode delamination cracks in laminated structures under cyclic loading is presented. The proposed fatigue method is based on linking a cohesive zone model for quasi-static crack growth and a Paris' law-like model described as a function of the energy release rate for the crack growth rate during cyclic loading. The J-integral has been applied to determine the energy release rate. Unlike other cohesive fatigue methods, the proposed method depends only on quasi-static properties and Paris' law parameters without relying on parameter fitting of any kind. The method has been implemented as a zero-thickness eight-node interface element for Abaqus and as a spring element for a simple finite element model in MATLAB. The method has been validated in simulations of mode I, mode II, and mixed-mode crack loading for both self-similar and non-self-similar crack propagation. The method produces highly accurate results compared with currently available methods and is capable of simulating general mixed-mode non-self-similar crack growth problems

A simulation method for high‐cycle fatigue‐driven delamination using a cohesive zone model

The use of cohesive elements to simulate delamination growth involves modeling the inelastic region existing ahead of the crack tip. Recent numerical and experimental findings indicate that the mixed-mode ratio varies at each material point within the inelastic region ahead of the crack tip during crack propagation, even for those specimens whose mixed-mode ratio is expected to be constant. Although the local variation of the mode mixity may adversely affect the predicted numerical results, most existing formulations do not take it into account. In this work, the mode-decomposed J-integral is implemented as a finite element post-processing tool to obtain the strain energy release rates and the mixed-mode ratio of the inelastic region as a whole, allowing the assessment of crack propagation in terms of energy dissipation and mixed-mode ratio computation. Different cohesive elements are assessed with this method.

Assessment of energy dissipation during mixed-mode delamination growth using cohesive zone models

The extended J-integral for 3D linear elastostatic crack problems and its application to mixed mode problems is investigated. In 3D, the decomposition of the J-integral into its parts corresponding to the symmetric mode I and both antisymmetric modes II and III is derived explicitly. The range of validity of the decomposition method is also discussed in the framework of linear elastic fracture mechanics (LEFM). It is shown analytically that in a general mixed mode case the antisymmetric part of the J-integral can be split into the parts associated with mode II and mode III only in the crack near-field.

J. Nickel

Papers

On the decomposition of the J-integral for 3D crack problems

A micromechanical interpretation of change in poisson's ratio in the presence of isotropic elastic damage