Damage Mechanics In The Effective Space In The Boundary Element Theory And Applications

Although recent development in boundary element method (BEM) in solid mechanics has brought the method of a maturity and differential equations of many types have been solved by using boundary element methods, the application in the analysis of damage mechanics problem hasn't been settled yet because damage mechanics is involving the locality and uneven of the region. So few papers about this topic can be found. The latest research results is the basis of this thesis and some further knowledge of BEM was discussed in this thesis, then do some try on the topic of BEM in mechanics. The formulations are gained in term of effective stress so that the combination of BEM and damage mechanics is achieved. The program named EPDBEM is developed for analyzing the damage mechanics problem through revising the program already existing. Some application of this program is present in the thesis. The work is listed below in details:1. The multi-region BEM elastic algorithm is translated to program codes by changing the boundary element program for single region.2. The BEM program that considers the domain integral of body force is developed in the basis of elastic BEM program discarding body force.3. Improved BEMECH so it can deal with anti-symmetry problem.4. Analyzed the rock mass with joint with boundary element method, and the effect of joint in excavations is discussed in contrast to the excavations in the rock mass without joint.5. Derived the elaso-plastic damage constitutive equations and also the system equations of boundary element method in terms of effective stress. With the assumption of effective strain used frequently in damage mechanics, the combination of damage mechanics and BEM is achieved - that is the boundary element method for elasto-plastic damage mechanics. The system equations is written and implemented in effective stress space. The numeric implement and also the algorithm to solve the system equations of matrix is discussed in details in the paper. Finally a program named EPDBEM for elasto-plastic damage problem is developed.6. Elasto-platic damage analysis about the excavation in rock mass is done with EPDBEM. In the meantime, elatic and elasto-platic analysis is done separately. The results of the three conditions is compared.7. The program for twice-excavation problem in rock mass is developed. A application in the large mine is present in the thesis. A Conclusion is that: the boundary displacement is affected by the twice excavation largely, in contrast that the stress distribution in the field of excavation is affect by the twice excavation little.8. Studied the crisp damage mechanics. a BEM program for crisp damage is developed and applied to the large mine problem.