Two-Dimensional Elastic Analysis by the Boundary Element Method.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
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This thesis analyzed a crack from a blunt notch and several classic fracture mechanics problems using the Boundary Element Method. Alternative formulations were considered, including direct and indirect methods, special crack tip elements, and higher order formulations. The indirect, or displacement discontinuity, method was selected as most appropriate. In order to fully evaluate the technique before attacking the major problem, a series of classical problems were solved, including a hole in a plate under uniaxial tension, a center crack plate and a crack eminating from a hole. Each problem was analyzed first considering an infinite plate boundary and again considering a finite plate boundary. Agreement with analytic solutions from various sources was excellent. A stress intensity analysis of the crack eminating from a blunt notch was performed and compared to an elastic finite element solution. This complicated problem is not published in the literature, and therefore comparison to finite element solution is indicated. The two solution techniques agreed to within a few percent and confirm that the indirect boundary element technique is applicable to this type of elastic solution.