Method for Resolving Contact Indeterminacy in Three-Dimensional Discontinuous Deformation Analysis

Because of the nonlinearity nature of contacts, real contact information in discontinuous computation is unknown before analysis. In standard three-dimensional (3D) discontinuous deformation analysis (3D DDA), the indeterminacies of the contacts arise from two aspects: the singular block boundaries and the nonsmooth frictional behavior. Because the contact occurs only at the first entrance position, the first entrance theory is the general physical law of block contacts. Therefore, the first entrance approach is proposed in this study to select the first entrance plane and to evaluate the related first entrance points, along which the contact forces would be applied. Furthermore, the procedure and criteria of the open-close iteration (OCI) for the 3D frictional contact problem is presented to determine the most suitable status and force of each contact. With this rigorous method, the information of each contact can be determined, such that the two kinds of the contact indeterminacies are resolved. The effectiveness of the proposed method is verified by three numerical tests, suggesting that the proposed method works at a practical level in accuracy and robustness. (c) 2018 American Society of Civil Engineers.