Numerical analysis of fracture problems with existing computational techniques has always been associated with difficulties due to the weakness of these techniques in assuming continuous deformation. Despite the solutions presented in local theories, the existence of some problems led researchers to use non-local theories. In the meantime, the theory of peridynamics is one of the most useful models in this field, using the characteristics of molecular mechanics and considering long-range forces. The high cost of calculations based on this theory and the confusion of border modeling are effective factors in combining this modeling with local models. With this work, the peridynamic model is used in the areas where non-local effects are effective, and the local model is used in other areas. Considering the optimality of using the finite strip model in solving plate problems, it is possible to use peridynamic theory with this local method in problems in this field. In this thesis, the combination of the finite strip method and peridynamics theory has been done for the first time using a coupled strip. With the present formulation, in addition to using advantage of peridynamcs and finite strip model, optimum time and economy condition are provided. Also, different boundary and loading conditions can be investigated, so more problems can be solved. According to the stated method, the formulation of the coupled method has been extracted for two cases of out-of-plane displacements and in-plane displacements. Based on the presented model, solved examples are presented to eva‎luate the accuracy and validity of the model. In this eva‎luation, the effect of peridynamic parameters, including the distance between material points and neighborhood radius, as well as the parameters of the finite strip, including the number of modes and strips, on the convergence has been investigated. The solved examples have been compared with the results extracted from the modeling in Abaqus software, which shows that peridynamic parameters are more effective in the convergence, and by reducing the distance between points and increasing the neighborhood radius, acceptable results can be achieved. In the following, by solving problems with different boundary conditions and non-uniform loading, it will be shown how to expand the solvable problems by using the finite strip method at the boundaries. The main advantage of peridynamics theory is the analysis of plates with discontinuity, in this thesis, plates with primary cracks and holes are considered, and crack propagation in them is investigated with the proposed coupling method, only by modeling the area with cracks or failure with peridynamics model.

مجتبي ازهري , سعيد صرامي

بيژن برومند

بشير موحديان عطار، حسين عموشاهي، مهدي زندي