The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to...The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.展开更多
In order to make the fracture cross-section of rock smooth in controlled cutting-blast, generally, two V-shape-notches on the inner wall of a shot hole are notched in symmetry along the design direction. A V-shape not...In order to make the fracture cross-section of rock smooth in controlled cutting-blast, generally, two V-shape-notches on the inner wall of a shot hole are notched in symmetry along the design direction. A V-shape notch approximately be considered as V-shape-fracture under certain condition. This paper gave the complex stress function of preformed V-shape-fracture under a blasting load. The stress field and displacement field at the tip of a preformed V-shape-fracture were derived with Westergaard's method, hence its stressintensity factor was obtained. To verify the derived results, blasting tests were made with concrete samples of 400mm×400mm×300mm, and all having, in the center, a drilled hole of 25mm in diameter and 200mm in height. The test result showed that the formulas derived are correct and effective.展开更多
This paper discusses the stability of the welding problems under different materials with same shearing modulus. Using the stability of Cauchy type integral while the smooth perturbation for the integral curve and Sob...This paper discusses the stability of the welding problems under different materials with same shearing modulus. Using the stability of Cauchy type integral while the smooth perturbation for the integral curve and Sobolev perturbation for the kernel density happening, the stability of complex stress functions are studied and errors of stress and displacement are given.展开更多
基金supported by National Natural Science Foundation of China(No.50675209)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education of China(No.200724).
文摘The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.
文摘In order to make the fracture cross-section of rock smooth in controlled cutting-blast, generally, two V-shape-notches on the inner wall of a shot hole are notched in symmetry along the design direction. A V-shape notch approximately be considered as V-shape-fracture under certain condition. This paper gave the complex stress function of preformed V-shape-fracture under a blasting load. The stress field and displacement field at the tip of a preformed V-shape-fracture were derived with Westergaard's method, hence its stressintensity factor was obtained. To verify the derived results, blasting tests were made with concrete samples of 400mm×400mm×300mm, and all having, in the center, a drilled hole of 25mm in diameter and 200mm in height. The test result showed that the formulas derived are correct and effective.
基金Supported by the National Natural Science Foundation of China(11171260)Science and Technology Foundation of Education Department of Fujian Province(JA11341)
文摘This paper discusses the stability of the welding problems under different materials with same shearing modulus. Using the stability of Cauchy type integral while the smooth perturbation for the integral curve and Sobolev perturbation for the kernel density happening, the stability of complex stress functions are studied and errors of stress and displacement are given.
