Analysis Of Cracked Bodies By Boundary Element Method

In this thesis, rock-like cracked materials were studied by boundary element method(BEM) with self-consistent schemes. The behavior of rock with orderly distributed cracks has been investigated. The propagating process of crack was simulated by marching the crack tip step by step.By means of computation of the instant equivalent elastic modulus with a self-consistent schemes and sub-domain BEM, the overall response of cracked body was analyzed by analyzing the propagation of one main crack.In the first place, some research methods such as Continuum Damage Mechanics, self-consistent scheme and other approaches had been examined. The previous works of other researchers have been reviewed.Secondly,the cracked body with single crack was investigated by sub-domain BEM. The cohesive crack model was introduced to the analysis of rock-like materials. An incremental iteration algorithm which has marching crack tip as the increment control variable had been established.Thirdly, the self-consistent schemes to determine the equivalent elastic modulus were discussed. The general formulations for the computation of equivalent elastic modulus were given.Finally, sub-domain BEM for analyzing cracked body had been investigated. The existence of friction sliding between crack surfaces leads to the non-symmetric and anisotropical equivalent elastic matrix, thus the relevant fundamentalsolutions should be found. Discontinuous boundary elements were used at the corners of sub-domains. An increment algorithm with three layer iterations was given. Some numerical examples were studied. The results seem to be satisfactory as comparing with the experimental data.