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...n. Rassineux [11] uses an octree procedure to generate internal nodes prior to the element generation. The current algorithm also uses an octree, but only as a node-spacing function. This approach tends to have a better control over the quality of the generated mesh and, apparently, decreases the amount of heuristic cleaning-up procedures. Moreover, the current algorithm specifically handles discontinuities in the domain or boundary of the model, such as evolving cracks. The algorithm has recently been used in realistic fracture simulations such as those presented in the work of Carter et al. [12]. The body of this paper is divided into three main sections. The following section describes the steps of the algorithm in some detail. Section 3 describes empirical measures of the quality of the elements generated for a number of examples. Section 4 describes empirical measures of the algorithm’s asymptotic performance. 2. Description of the Algorithm The input to the algorithm is a faceted description of the boundary of a region to be meshed. This is 77An Algorithm for 3D Mesh Generation given by a list of nodes defined by their coordinates, and a list of triangular faces defined by their ...

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...update level sets for two- and three-dimensional crack propagation. Some of the prominent numerical methods used for planar and non-planar crack growth in three dimensions are: finite element methods =-=[12, 13]-=-, boundary element-based techniques [14–19], and boundary integral equations [20, 21]. Gao and Rice [22] and Lai et al. [23] used perturbation analysis to study planar and non-planar cracks, whereas L...

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...e principles of linear elastic fracture mechanics provide a sound tool to carry out damage tolerant analyses, and hence the development of numerical models for three-dimensional crack growth of multiple cracks and their interactions is important. Exact solutions for the evolution of arbitrary-shaped cracks in 3-dimensional structural components are not available, and hence numerical methods are the only recourse for three-dimensional fatigue crack growth simulations. Some of the prominent numerical methods used for modeling fatigue crack growth are: finite element and boundary element methods [15,21,6,11,7], boundary integral equations [42], finite element alternating method [41,26], and the dislocation distribution approach [18,9]. Much of the progress in finite element remeshing algorithms and the capability to carry out three-dimensional crack modeling and fatigue crack propagation in complex structural components is due to contributions of the Cornell Fracture Group 2 . The finite element framework is particularly attractive for it provides the ease and flexibility of modeling complex structural components with arbitrary boundary conditions, nonlinear material behavior, and anisotropic mater...

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...l changes; and videogames and special effects for feature films often animate exploding and breaking objects. The simulation of cutting and fracture of deformable objects encompasses two main aspects =-=[12]-=-: the geometric and topological aspect, concerned with the synthesis of crack surfaces and how these surfaces affect the discretization of the domain in the physically-based simulation; and the mechan...

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...om She and Guo [20]. The maxima SIF tend to the long crack solution for cracks with very low B/a, and the middle plate SIF KImp tend to the limit 2D solution KI,2D as B/a becomes large and the cracks get shorter. Moreover, the separation of the KImax/KI,2D curve from the KImp/KI,2D curve of the short cracks shows that their KImax value is higher than the reference KI,2D value, about 3% higher for the Poisson coefficient 0.3 used in these numerical simulations, see Góes et al. [16] for details. GROWTH OF EDGE CRACKS WITH INITIALLY STRAIGHT FRONTS IN LARGE PLATES he specialized FRANC3D code [21] was used to simulate the growth of large and small edge cracks with an idealized initially straight front in large plates, supposing LEFM conditions. Since the solution of LE problems is unique and proportional to the imposed load P, the calculated SIF Kcal along the crack front can be interpreted as a shape function, hence Kmax PKcal, Kmin PRKcal, R Kmin/Kmax, and K Kmax – Kmin. Without loss of generality, the analyses developed here considered R 0 and P 1, thus in the propagation cases described below K Kmax Kcal. T R.C.O. Góes et alii, Frattura ed Integrità Strutturale...