Showing papers on "Extended finite element method published in 2019"
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04 Jun 2019
180 citations
TL;DR: In this article, a composite double cantilever beam (DCB) specimen is modeled in ABAQUS and delamination propagation is simulated using three numerical methods: Virtual crack closure technique (VCCT), cohesive zone modeling (CZM), and extended finite element method (XFEM).
107 citations
TL;DR: In this paper, a hybrid approach combining the EDFM (embedded discrete fracture model) and XFEM (extended finite element method) is proposed to investigate the effects of poroelastic properties and permeability on hydraulic fracturing in an anisotropic medium.
79 citations
TL;DR: Comparisons show that XIGA-Jaya performs the best of all considered techniques, and is demonstrated by using various NURBS orders to reduce the number of elements, provide fast simulation and achieve best convergence compared with XFEM.
67 citations
TL;DR: In this paper, Wu et al. compared the PF-CZM with the XFEM for the modeling of cohesive fracture induced localized failure in solids, and showed that the latter is more suitable for complex crack propagation.
66 citations
TL;DR: In this paper, an efficient numerical model is proposed to simulate the hydro-mechanical coupling in the fractured vuggy porous media containing multi-scale fractures and vugs.
65 citations
TL;DR: In this paper, a mechanistic methodology for simulating microstructurally-sensitive (tortuosity and propagation rate) fatigue crack growth in ductile metals is introduced which utilises the recently introduced dislocation configurational stored energy as the measure of the driving force.
Abstract: A mechanistic methodology for simulating microstructurally-sensitive (tortuosity and propagation rate) fatigue crack growth in ductile metals is introduced which utilises the recently introduced dislocation configurational stored energy as the measure of the driving force. The model implements crystal plasticity finite element simulations using the eXtended Finite Element Method (XFEM) to represent the crack. Two methods of predicting the direction of growth (based on the crystallographic slip or the maximum principal stress) are compared. The crystallographic slip based direction model is shown to predict microstructurally-sensitive fatigue crack growth in single crystals which displays many features of path tortuosity that have been observed experimentally. By introducing a grain boundary, the crystallographic model is shown to capture behaviour similar to that observed experimentally including crack deflection and retardation at the grain boundaries. Finally, two experimental examples of fatigue cracks growing across three grains are analysed, and the model is shown to capture the correct crystallographic growth paths in both cases.
65 citations
TL;DR: A simple procedure for the local near-orthogonalization of enrichment functions is introduced, which significantly improves the conditioning of the resulting system matrices, while requiring only minor modifications to the initial method.
62 citations
TL;DR: A novel multi-grid (MG) reanalysis method is formulated under the framework of the extended finite element method (XFEM) and it is shown that the presented algorithm is very accurate and can efficiently reduce the computational cost.
59 citations
TL;DR: In this paper, the authors provide a critical literature review, emphasizing on the mathematical, conceptual and implementation particularities that lead to the specific advantages and disadvantages of each method, as well as to offer numerical examples that help illustrate these features.
Abstract: Three alternative approaches, namely the extended/generalized finite element method (XFEM/GFEM), the scaled boundary finite element method (SBFEM) and phase field methods, are surveyed and compared in the context of linear elastic fracture mechanics (LEFM). The purpose of the study is to provide a critical literature review, emphasizing on the mathematical, conceptual and implementation particularities that lead to the specific advantages and disadvantages of each method, as well as to offer numerical examples that help illustrate these features.
56 citations
TL;DR: In this article, a continuum damage mechanics (CDM) based methodology for high cycle fatigue crack growth simulations is proposed and implemented in the framework of extended finite element method (XFEM), a new criterion is proposed based on damage evolution to identify the appropriate definition of stress triaxiality for acquiring the constraint effect on the stress state correctly.
TL;DR: A novel and effective computational approach based on polygonal XFEM (named as PolyXFEM) for the analysis of two-dimensional (2D) linear elastic fracture mechanics problems, equipped with a new numerical integration technique that uses the concept of Cartesian transformation method (CTM) overpolygonal domains.
TL;DR: In this article, elasto-plastic creep crack growth simulations are performed using continuum damage mechanics and extended finite element method using Liu-Murakami creep damage model and explicit ti...
Abstract: In the present work, elasto-plastic creep crack growth simulations are performed using continuum damage mechanics and extended finite element method. Liu–Murakami creep damage model and explicit ti...
TL;DR: In this paper, a computational approach to simulate the influence of intra-laminar voids on cracking in composite laminates is developed, which combines finite element models of two scales: a micro-scale model, where the fibers and voids are modeled explicitly, and a meso-scale one where the cracking phenomenon is captured on the ply scale.
Abstract: Voids are an important type of manufacturing defects in fiber-reinforced composites. Matrix cracking is sensitive to the presence of voids. Although this cracking occurs at the ply scale, its dynamics is strongly affected by ply’s microstructure, in particular, fiber distribution, fiber content, and the presence of voids. In the current study, a computational approach to simulate the influence of intra-laminar voids on cracking in composite laminates is developed. The approach combines finite element models of two scales: a micro-scale model, where the fibers and voids are modeled explicitly, and a meso-scale model, where the cracking phenomenon is captured on the ply scale. The micro-scale model, incorporating plasticity and damage in the matrix, provides input for the meso-scale model, which simulates the progressive cracking by means of the extended finite element method. The methodology is applied to investigate the effect of voids on the density of transverse cracks in cross-ply laminates in function of the quasi-static tensile load. Different sizes and contents of voids, which are chosen based on experimental micro-computed tomography data, are simulated. The numerical experiments show that the presence of voids leads to earlier start of the cracking, with the crack density evolution less sensitive to voids.
TL;DR: In this article, the authors investigated the impact of stress shadowing effects on the required pressure for crack propagation and the resulting fracture geometry in multilayered formations, and proposed an extended finite element method (XFEM) to simulate hydraulic fracturing processes considering the propagation of several vertical nonplanar fluid-driven fractures.
TL;DR: In this article, the phase field method (PFM) is integrated with multiscale extended finite element method (MsXFEM) to simulate crack growth in highly heterogeneous materials i.e. matrix with periodically distributed voids and particles.
TL;DR: In this article, the authors investigated the brittle failure mechanism of rock slopes with non-persistent en-echelon joints using the extended finite element method (XFEM) and proposed a novel geometrical method distinguished from the conventional level set method is proposed to describe the cracks in the XFEM.
TL;DR: In this paper, the recently proposed linear smoothed extended finite element method (LSmXFEM) is employed to simulate the fatigue crack growth, which does not require special numerical integration technique to integrate the terms in the stiffness matrix.
TL;DR: In this article, the results of a series of high cycle fatigue (HCF) experiments on steel welded T-joints, tested under constant amplitude three-point bending, were reported.
TL;DR: By coupling the phantom node method with the mesh cut technique in the framework of the extended finite element method (XFEM), an enhanced XFEM for the propagation of complex branched cracks is proposed as discussed by the authors.
Abstract: By coupling the phantom node method with the mesh cut technique in the framework of the extended finite element method (XFEM), an enhanced XFEM for the propagation of complex branched cracks is proposed. The proposed method aims to solve the complex branched crack problems. Additionally, instead of the constant crack propagation length, a novel crack propagation scheme is introduced into the XFEM, in which the crack propagation length is a variable which is determined by two trial calculations. The feasibility and the accuracy of the proposed method are validated by numerical tests. The numerical results show that the enhanced XFEM can easily handle the complex branched crack problems, and it has the higher accuracy than the standard XFEM. Meanwhile, a smooth crack path can be obtained using the novel crack propagation scheme.
TL;DR: The implementation of an XFEM element for hydraulic fracturing in porous medium in Abaqus has the capability of intersecting fractures inside an element and includes coupled hydro-mechanical behaviour and fluid exchange between fracture and the porous medium.
TL;DR: By applying these techniques to different types of enrichment functions, namely polynomial, discontinuous and singular, higher order convergence rates can be obtained while keeping condition number growth rates similar to the ones corresponding to standard finite elements.
TL;DR: In this paper, a phantom nodes-based extended finite element method is used to predict the fatigue crack initiation of steel material, considering a prediction by XFEM of coupon tests made of steel grades S355 and S690.
TL;DR: In this article, the authors present a fatigue analysis of a type of fillet welded joint representative of one main joint of the steel box girder of the railway bridge of the Alcacer do Sal railway bridge.
TL;DR: In this paper, a fracture process zone ahead of the physical crack tip is represented by means of cohesive tractions from which the energy release rate, and thus the stress intensity factor can be extracted for an elastic-plastic material.
Abstract: Structures are subjected to cyclic loads that can vary in direction and magnitude, causing constant amplitude mode I simulations to be too simplistic. This study presents a new approach for fatigue crack propagation in ductile materials that can capture mixed-mode loading and overloading. The extended finite element method is used to deal with arbitrary crack paths. Furthermore, adaptive meshing is applied to minimize computation time. A fracture process zone ahead of the physical crack tip is represented by means of cohesive tractions from which the energy release rate, and thus the stress intensity factor can be extracted for an elastic-plastic material. The approach is therefore compatible with the Paris equation, which is an empirical relation to compute the fatigue crack growth rate. Two different models to compute the cohesive tractions are compared. First, a cohesive zone model with a static cohesive law is used. The second model is based on the interfacial thick level set method in which tractions follow from a given damage profile. Both models show good agreement with a mode I analytical relation and a mixed-mode experiment. Furthermore, it is shown that the presented models can capture crack growth retardation as a result of an overload. A© 2019 The Authors. InternationalA JournalA forA NumericalA MethodsA inA Engineering Published by John Wiley & Sons, Ltd.
TL;DR: In this paper, a numerical manifold method (NMM) model was developed to analyze the fully dynamic consolidation of fractured porous media in terms of Biot's theory of saturated porous media with incompressible solid and fluid phases.
TL;DR: In this article, a data transfer scheme is proposed to evaluate the stresses at the spatial mirror point and the derivative of strain energy density is calculated by surface approximation of the strain energy densities.
01 Mar 2019-Microsystem Technologies-micro-and Nanosystems-information Storage and Processing Systems
TL;DR: In this article, an extended finite element method (XFEM) is used to simulate two-dimensional and three-dimensional microcracks initiation and propagation through versatile material models for structures.
Abstract: Various methodologies and
frameworks have been developed for extended finite element method (XFEM) to simulate two-dimensional and three-dimensional microcrack initiation and propagation through versatile material models for structures. In addition, mixed-mode cohesive zone is investigated and estimated for delamination, matrix cracking and fiber breakage in composite laminate models. The validation of Multiscale modeling for the fiber uniformity during the tensile behavior, prediction of crack and properties of composite material analyzed by XFEM modeling for the damage modes and comparison with the experimental work and the author’s recent experimental case study is presented. The further development is application of extended cohesive damage modelling (ECDM) without the additional complications of degrees of freedom and effective simulation of multicrack propagation and damage model. The capabilities of ECDM to work for single mode delamination and mixed mode delamination with a better efficiency and accuracy are well explained. The study simplifies the application of extended FEM for the prediction of multiple cracks applied to carbon fiber reinforced composites (CFRCs), hence provides a better understanding for extended cohesive damage modelling for the recent developments.
TL;DR: A model for crack propagation in 2D at the microscale in cortical bone was developed using the extended finite element method by combining the maximum principal strain criterion with an additional interface damage formulation in the cement line to capture crack deflections at the osteon boundaries as observed in experiments.
Abstract: Reliable tools for fracture risk assessment are necessary to handle the challenge with an aging population and the increasing occurrence of bone fractures. As it is currently difficult to measure local damage parameters experimentally, computational models could be used to provide insight into how cortical bone microstructure and material properties contribute to the fracture resistance. In this study, a model for crack propagation in 2D at the microscale in cortical bone was developed using the extended finite element method (XFEM). By combining the maximum principal strain criterion with an additional interface damage formulation in the cement line, the model could capture crack deflections at the osteon boundaries as observed in experiments. The model was used to analyze how the Haversian canal and the interface strength of the cement line affected the crack trajectory in models depicting osteons with three different orientations in 2D. Weak cement line interfaces were found to reorient the propagating cracks while models with strong interfaces predicted crack trajectories that penetrated the cement line and propagated through the osteons. The presented model is a promising tool that could be used to analyze how local, age-related material changes influence the crack trajectory and fracture resistance in cortical bone.
TL;DR: A weak Galerkin (WG) finite element method for the Navier–Stokes equations in the primal velocity–pressure formulation and optimal-order error estimates are established for the corresponding numerical approximations.