This work calculates the stress intensity factors (SIFs) at the crack tips, predicts the crack initiation angles, and simulates the crack propagation path in the two-dimensional cracked anisotropic materials using the single-domain boundary element method (BEM) combined with maximum circumferential stress criterion. The BEM formulation, based on the relative displacements of the crack tip, is used to determine the mixed-mode SIFs and simulate the crack propagation behavior. Numerical examples of the application of the formulation for different crack inclination angles, crack lengths, degree of material anisotropy, and crack types are presented. Furthermore, the propagation path in Cracked Straight Through Brazilian Disc (CSTBD) specimen is numerically predicted and the results of numerical and experimental data compared with the actual laboratory observations. Good agreement is found between the two approaches. The proposed BEM formulation is therefore suitable to simulate the process of crack propagation. Additionally, the anisotropic rock slope failure initiated by the tensile crack can also be analyzed by the proposed crack propagation simulation technique.
Itasca Flac 6 0 Cracked
Example 1: Isotropic Cracked Brazilian DiscIn order to compare our results with the existing published results, an isotropic and cracked Brazilian disc with a central slant crack is considered. The geometry of the problem is that of a thin circular disc of radius and thickness with a central crack of length , loaded with a pair of concentrated and diametral compressive load , as shown in Figure 5. The outer boundary and crack surface are discretized with 28 continuous and 10 discontinuous quadratic elements, respectively. Two cases are analyzed: (1) , the crack angle varies between 0 and , and (2) , varies between 0.1 and 0.7. The two normalized SIFs, and , calculated with the BEM program for these two cases, are compared with those obtained numerically by Atkinson et al. [42] and Chen et al. [28]. The results are shown in Tables 1 and 2. In general, a good agreement is found among these three methods.
The proposed BEM formulation combined with the maximum circumferential stress criterion is developed to predict the angle of crack initiation and to simulate the path of crack propagation under mixed-mode loading. The crack propagation process in the cracked materials is numerically estimated by two-dimensional stress and displacement analysis. In order to understand the behavior of cracks under mixed-mode loading, the BEM program is applied.
A formulation of the BEM, based on the relative displacements near the crack tip, is utilized to determine the mixed-mode SIFs of anisotropic rocks. Numerical examples for the determination of the mixed-mode SIFs for a CSTBD specimen are presented for isotropic and anisotropic media. The numerical results obtained by the proposed method are in good agreement with those reported by previously published results. In addition, the SIFs for various crack geometry and loading type such as a curved crack under far-field tensile stress and a cracked body hanging by its own weight are also determined by the proposed BEM formulation. The numerical results obtained by this study are in agreement with those reported by previously published results.
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