In the framework of the finite deformation theory, the plastic collapse analysis of thin-walled pipes subjected to the internal pressure is conducted on the basis of the unified strength criterion （USC）. An analytic...In the framework of the finite deformation theory, the plastic collapse analysis of thin-walled pipes subjected to the internal pressure is conducted on the basis of the unified strength criterion （USC）. An analytical solution of the burst pressure for pipes with capped ends is derived, which includes the strength differential effect and takes the influence of strength criterion on the burst pressure into account. In addition, a USC- based analytical solution of the burst pressure for end-opened pipes under the internal pressure is obtained. By discussion, it is found that for the end-capped pipes, the influence of different yield criteria and the strength differential effect on the burst pressure are significant, while for the end-opened pipes, the burst pressure is independent of the specific form of the strength criterion and strength difference in tension and compression.展开更多
Although curved pipes are used in a wide range of applications, flow in curved pipes is relatively less well known than that in straight ducts. This paper presents a computational fluid dynamics study of isothermal la...Although curved pipes are used in a wide range of applications, flow in curved pipes is relatively less well known than that in straight ducts. This paper presents a computational fluid dynamics study of isothermal laminar single-phase flow of water in a hollow helical pipe at various Reynolds numbers. The ranging of Reynolds numbers of fluid was from 703.2 to 1687.7. The three dimensional governing equations for mass and momentum have been solved. It was found that with increasing Reynolds number and creation of centrifugal forces, a high velocity and pressure region occurs between two tubes, at the outer side of the hollow helical pipe walls. Friction factor decreases as the tendency for turbulence increases.展开更多
The hollow spherical joints welded with circular pipes applied to the National Swimming Center of China are subjected to large bending moments, but the influence of bending moments is not considered in the design equa...The hollow spherical joints welded with circular pipes applied to the National Swimming Center of China are subjected to large bending moments, but the influence of bending moments is not considered in the design equations in Technical Specification for Latticed Shells. Based on the von Mises yield criterion, multilinear isotropic hardening rule and associated flow rule, the elasto-plastic finite element model is put forward to analyze the behavior of the joints, and a calculation method for the joints under bending moments or eccentric loads is proposed. It is shown by the analytical results of joint that the stiffening rib can improve the ultimate bearing capacity by 10% for joints under axial tensile load, by 40% for joints under axial compressive load, and by 50% for joints under bending moment. The unified calculation equations for joints with or without stiffening rib are put forward, which can be applied to calculating the ultimate bearing capacity of the hollow spherical joints with circular pipes under eccentric loads.展开更多
基金Project supported by the National Natural Science Foundation of China (Nos. 51079128 and11172265)the Natural Science Foundation of Zhejiang Province of China (No. Y1101107)
文摘In the framework of the finite deformation theory, the plastic collapse analysis of thin-walled pipes subjected to the internal pressure is conducted on the basis of the unified strength criterion （USC）. An analytical solution of the burst pressure for pipes with capped ends is derived, which includes the strength differential effect and takes the influence of strength criterion on the burst pressure into account. In addition, a USC- based analytical solution of the burst pressure for end-opened pipes under the internal pressure is obtained. By discussion, it is found that for the end-capped pipes, the influence of different yield criteria and the strength differential effect on the burst pressure are significant, while for the end-opened pipes, the burst pressure is independent of the specific form of the strength criterion and strength difference in tension and compression.
文摘Although curved pipes are used in a wide range of applications, flow in curved pipes is relatively less well known than that in straight ducts. This paper presents a computational fluid dynamics study of isothermal laminar single-phase flow of water in a hollow helical pipe at various Reynolds numbers. The ranging of Reynolds numbers of fluid was from 703.2 to 1687.7. The three dimensional governing equations for mass and momentum have been solved. It was found that with increasing Reynolds number and creation of centrifugal forces, a high velocity and pressure region occurs between two tubes, at the outer side of the hollow helical pipe walls. Friction factor decreases as the tendency for turbulence increases.
基金National Natural Science Foundation of China (No 50608054)
文摘The hollow spherical joints welded with circular pipes applied to the National Swimming Center of China are subjected to large bending moments, but the influence of bending moments is not considered in the design equations in Technical Specification for Latticed Shells. Based on the von Mises yield criterion, multilinear isotropic hardening rule and associated flow rule, the elasto-plastic finite element model is put forward to analyze the behavior of the joints, and a calculation method for the joints under bending moments or eccentric loads is proposed. It is shown by the analytical results of joint that the stiffening rib can improve the ultimate bearing capacity by 10% for joints under axial tensile load, by 40% for joints under axial compressive load, and by 50% for joints under bending moment. The unified calculation equations for joints with or without stiffening rib are put forward, which can be applied to calculating the ultimate bearing capacity of the hollow spherical joints with circular pipes under eccentric loads.
