Study On Problems Of Combine Defectiveness Subjected By SH Wave

By using Green's Function method and the method of crack-division, the interaction problems of combined defectiveness including circular cavity, inclusion with double cracks of any limited lengths near cavity or inclusion subjected by SH-wave were studied in the range of linear dynamic elasticity. Firstly a suitable Green's function, which is a fundamental solution of displacement field for an elastic space possessing circular cavity or inclusion with a linear crack while bearing out-of-plane harmonic line source force at any point is constructed for the present problem. Then using the method of crack-division, integration for solution is established:while the scattering problems of SH-wave by circular cavity or inclusion with a linear crack are studied, reverse stresses are inflicted along the second crack, that is, out-of-plane harmonic line source forces which are equal in the quantity but opposite in the direction to the stresses produced for the reason of SH-wave scattering by cavity or inclusion with a linear crack are loaded at the region where cracks will appear, so the second crack can be made out. So the expression of displacement and stress is established while cavity or inclusion and double cracks are existent. Using the expression dynamic stress concentration near the cavity or inclusion is discussed.By using Green's Function method and the method of crack-division and the method of multi-polar coordinate system, the interaction problem of multiple circular inclusions with an linear crack in half space by SH-wave is studied. Firstly a suitable Green's function, which is a fundamental solution of displacement field for half elastic space possessing multiple circular inclusions while bearing out-of-plane harmonic line source force at any point is constructed for the present problem. Then using the method of crack-division, integration for solution is established:while the scattering problems of SH-wave by multiple circular inclusions is studied, reverse stresses are inflicted along the crack, that is, out-of-plane harmonic line source forces which are equal in the quantity but opposite in the direction to the stresses produced for the reason of SH-wave scattering by multiple inclusions are loaded at the region where crack will appear, so the crack can be made out. So the expression of displacement and stress was established while multiple inclusions and crack are existent. Employing the expression dynamic stress concentration near the inclusion was discussed.The works in detail have covered three areas:1. The problem of SH-wave scattering and dynamic stress concentration by circular cavity with double cracks of any limited lengths near the cavity is investigated. Using the Green's function which is suitable to the present problem, the expression of displacement and stress is established while the interaction of circular cavity with cracks is studied with crack-division technique. Dynamic stress concentration near the circular cavity is studied. An example and results are given. The influences of wave number, incident angles of SH-wave, and the geometrical location of the circular cavity and crack are discussed.2. The problem of SH-wave scattering and dynamic stress concentration by circular inclusion with double cracks of any limited lengths near the inclusion is investigated. Using the Green's function which is suitable to the present problem, the expression of displacement and stress is established while the interaction of circular inclusion with cracks is studied with crack-division technique. Dynamic stress concentration near the circular inclusion is studied. An example and results are given. The influences of wave number, incident angles of SH-wave, the geometrical location of the circular cavity and crack and the combination of different media parameters are discussed.3. The problem of SH-wave scattering and dynamic stress concentration by multiple circular inclusions with a linear crack near the inclusions are investigated. Using the Green's function which is suitable to the present problem, the expression of displacement and stress is established while the interaction of circular inclusions with crack is studied with crack-division technique. Dynamic stress concentration near the circular inclusion is studied. An example and results are given. The influences of wave number, incident angles of SH-wave, the geometrical location of the circular cavity and crack and the combination of different media parameters are discussed.