Please use this identifier to cite or link to this item: http://localhost:8081/xmlui/handle/123456789/10529
Title: NUMERICAL SIMULATION OF FATIGUE CRACK PROBLEMS USING ELEMENT FREE GALERKIN METHOD
Authors: Sanjay, Vispute Sumit
Keywords: MECHANICAL INDUSTRIAL ENGINEERING;FATIGUE CRACK PROBLEMS;ELEMENT FREE GALERKIN METHOD;FATIGUE CRACK GROWTH
Issue Date: 2010
Abstract: The analysis of fatigue crack growth is essential to ensure the reliability of structures under cyclic loading conditions. Cracks, as a result of manufacturing defects or localized damage, may extend until brittle fracture. occurs. The aim of this dissertation is to develop algorithms which can effectively simulate the fatigue growth of cracks. The propagation is modeled by successive linear extensions, which are determined by the stress intensity factors (SIFs) obtained after a linear elastic analysis. The direction of these increments is determined from the maximum principle stress criterion. Meshfree methods were found to be particularly appropriate to solve these kinds of crack propagation problems. In this dissertation work, a meshfree element free Galerkin method (EFGM) is used to simulate crack growth problems. An algorithm has been developed along with vector level sets to model crack growth. In this algorithm, level set is described by the sign of the level set function and the components of the closest point projection to the surface. Moreover, only nodal data is required to describe the crack. Thus, there is no need to introduce a geometrical entity for crack trajectory to update the level sets. The nodal description is updated as the crack propagates by geometric equations. The partition of unity (PU) enrichment is used in Element Free Galerkin method to accurately capture the near tip displacement field. This enrichment approach uses a jump function accounting for the displacement discontinuity along the crack faces, and the Westergaard's enrichment near the crack tip to capture crack tip singularity. These enrichments, being extrinsic, can be limited only to the nodes surrounding the crack, and are naturally coupled with level sets. Due to this coupling, the nodes for Heaviside and tip enrichment can be automatically identified with the update of level set. Few model problems are solved by developed algorithm, and the results obtained from developed algorithm are compared with those available in literature.
URI: http://hdl.handle.net/123456789/10529
Other Identifiers: M.Tech
Research Supervisor/ Guide: Singh, I. V.
Mishra, B. K.
metadata.dc.type: M.Tech Dessertation
Appears in Collections:MASTERS' DISSERTATIONS (MIED)

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