The Finite Element Method of Lines （FEMOL） is a semi-analytic approach and takes a position between FEM and analytic methods. First, FEMOL in Fracture Mechanics is presented in detail. Then, the method is applied to...The Finite Element Method of Lines （FEMOL） is a semi-analytic approach and takes a position between FEM and analytic methods. First, FEMOL in Fracture Mechanics is presented in detail. Then, the method is applied to a set of examples such as edge-crack plate, the central-crack plate, the plate with cracks emanating from a hole under tensile or under combination loads of tensile and bending. Their dimensionless stress distribution, the stress intensify factor （SIF） and crack opening displacement （COD） are obtained, and comparison with known solutions by other methods are reported. It is found that a good accuracy is achieved by FEMOL. The method is successfully modified to remarkably increase the accuracy and reduce convergence difficulties. So it is a very useful and new tool in studying fracture mechanics problems.展开更多
The Self-Similar Crack Expansion (SSCE) method is used to calculate stress intensity factors for three-dimensional cracks in an infinite medium or semi-infinite medium by the boundary integral element technique, where...The Self-Similar Crack Expansion (SSCE) method is used to calculate stress intensity factors for three-dimensional cracks in an infinite medium or semi-infinite medium by the boundary integral element technique, whereby, the stress intensity factors at crack tips are determined by calculating the crack-opening displacements over the crack surface. For elements on the crack surface, regular integrals and singular integrals are precisely evaluated based on closed form expressions, which improves the accuracy. Examples shaw that this method yields very accurate results for stress intensity factors of penny-shaped cracks and elliptical cracks in the full space, with errors of less than 1% as compared with analytical solutions. The stress intensity factors of subsurface cracks ate in good agreement with other analytical solutions.展开更多
Three-dimensional edge cracks are analyzed using the Self-SimilarCrack Expansion (SSCE)method with a boundary integral equationtechnique. The boundary integral equations for surface cracks in ahalf space are presented...Three-dimensional edge cracks are analyzed using the Self-SimilarCrack Expansion (SSCE)method with a boundary integral equationtechnique. The boundary integral equations for surface cracks in ahalf space are presented based on a half space Green'sfunction(Mindlin, 1936). By using the SSCe method, the stressintensity factors are determined by crack-opening displacement overthe crack surface. In discrete boundary integral equations, theregular and singular integrals on the crack sur- face elements areevaluated by an analytical method, and the closed form expressions ofthe integrals are given for subsurface cracks and edge cracks.展开更多
文摘The Finite Element Method of Lines （FEMOL） is a semi-analytic approach and takes a position between FEM and analytic methods. First, FEMOL in Fracture Mechanics is presented in detail. Then, the method is applied to a set of examples such as edge-crack plate, the central-crack plate, the plate with cracks emanating from a hole under tensile or under combination loads of tensile and bending. Their dimensionless stress distribution, the stress intensify factor （SIF） and crack opening displacement （COD） are obtained, and comparison with known solutions by other methods are reported. It is found that a good accuracy is achieved by FEMOL. The method is successfully modified to remarkably increase the accuracy and reduce convergence difficulties. So it is a very useful and new tool in studying fracture mechanics problems.
基金the National Institute of Standards and Technologythe Army Office of Research
文摘The Self-Similar Crack Expansion (SSCE) method is used to calculate stress intensity factors for three-dimensional cracks in an infinite medium or semi-infinite medium by the boundary integral element technique, whereby, the stress intensity factors at crack tips are determined by calculating the crack-opening displacements over the crack surface. For elements on the crack surface, regular integrals and singular integrals are precisely evaluated based on closed form expressions, which improves the accuracy. Examples shaw that this method yields very accurate results for stress intensity factors of penny-shaped cracks and elliptical cracks in the full space, with errors of less than 1% as compared with analytical solutions. The stress intensity factors of subsurface cracks ate in good agreement with other analytical solutions.
文摘Three-dimensional edge cracks are analyzed using the Self-SimilarCrack Expansion (SSCE)method with a boundary integral equationtechnique. The boundary integral equations for surface cracks in ahalf space are presented based on a half space Green'sfunction(Mindlin, 1936). By using the SSCe method, the stressintensity factors are determined by crack-opening displacement overthe crack surface. In discrete boundary integral equations, theregular and singular integrals on the crack sur- face elements areevaluated by an analytical method, and the closed form expressions ofthe integrals are given for subsurface cracks and edge cracks.
