The interfacial behavior of pipe joints is studied in this paper. Firstly, through nonlinear fracture mechanics, the analytical expressions of interfacial shear stress and the load- displacement relationship at loaded...The interfacial behavior of pipe joints is studied in this paper. Firstly, through nonlinear fracture mechanics, the analytical expressions of interfacial shear stress and the load- displacement relationship at loaded end of pipe joints under torsion loads are obtained. Thus the shear stress propagation and the debonding process of the whole interface for different bond lengths can be predicted. Secondly, through the analytical solutions, the influences of different bond lengths on the load-displacement curve and the ultimate load are studied. The stress trans- fer mechanism, the interface crack propagation and the ductility behavior of the joints can be explained.展开更多
Analysis as well as application of ultra-high pressure hydraulic system and elements has become a trend.The structure and operation principle of a new type of ultra-high pressure pipe joint is introduced.The structure...Analysis as well as application of ultra-high pressure hydraulic system and elements has become a trend.The structure and operation principle of a new type of ultra-high pressure pipe joint is introduced.The structure of the new type of ultra-high pressure pipe joint is simple and is easy to be produced.The finite element model on two working conditions(preload condition with 30 N·m torque and static-loading condition with 70 MPa pressure)is built and computed.The width of contact area,the equivalent stress status,as well as the contact pressure status are plotted and analyzed.According to the national standard,test on air-tightness,blasting,and cyclic endurance is conducted and the results show that the new type of ultra-high pressure pipe joint has the sealability for ultra-high pressure up to 70 MPa,and the DN6 ultra-high pressure pipe joint can provide effective seal under70 MPa fluid pressure.The research can provide a thinking and method on designing ultra-high pressure pipe joint and push forward the development of ultra-high pressure hydraulic system.展开更多
Double shoulder drill pipe joint(DSJ)is a novel thread structure which appears in recent years.Its strength reduced efficiently while the structure design is not appropriately,for the DSJ’s mechanical behaviors weren...Double shoulder drill pipe joint(DSJ)is a novel thread structure which appears in recent years.Its strength reduced efficiently while the structure design is not appropriately,for the DSJ’s mechanical behaviors weren’t well studied.In this paper a 3D whole structure finite element model of DSJ was established based on the Principle of Virtual Work,and validated the model’s computing results by experimental results.The authors analyzed the stress and strain distribution with the 3D whole structure finite element model’s computing results under torque moment,compression force,tension load,and bend moment.And then acquired the DSJ’s mechanical behaviors under each load.The research works of this paper refer accordance to recognize and design the DSJ.展开更多
The out-of-plane distortion induced in a multi-pass circumferential fillet welding of tube to pipe under different weld sequences and directions was studied using Finite Element Method(FEM) based Sysweld software and ...The out-of-plane distortion induced in a multi-pass circumferential fillet welding of tube to pipe under different weld sequences and directions was studied using Finite Element Method(FEM) based Sysweld software and verified experimentally. The FEM analyses consisted of thermal and mechanical analyses.Thermal analysis was validated with experimental transient temperature measurements. In the mechanical analysis, three different weld sequences and directions were considered to understand the mechanism of out-of-plane distortion in the tube to pipe T-joints. It was learnt that the welding direction plays a major role in minimizing the out-of-plane distortion. Further, during circumferential fillet welding of the tube to pipe component, the out-of-plane distortion generated in the x direction was primarily influenced by heat input due to the start and stop points, whereas the distortion in the z direction was influenced by time lag and welding direction. The FEM predicted distortion was compared with experimental measurements and the mechanism of out-of-plane distortion was confirmed.展开更多
基金supported by the Science and Technology Scheme of Guangzhou City(No.201510010013)the Science and Technology Scheme of Guangdong Province(No.2012A030200003)the National Natural Science Foundation of China(No.11032005)
文摘The interfacial behavior of pipe joints is studied in this paper. Firstly, through nonlinear fracture mechanics, the analytical expressions of interfacial shear stress and the load- displacement relationship at loaded end of pipe joints under torsion loads are obtained. Thus the shear stress propagation and the debonding process of the whole interface for different bond lengths can be predicted. Secondly, through the analytical solutions, the influences of different bond lengths on the load-displacement curve and the ultimate load are studied. The stress trans- fer mechanism, the interface crack propagation and the ductility behavior of the joints can be explained.
基金Supported by the 2015 Industrial Transformation and Upgrading of Strong Base Project(TC150B5C0-29)the National Key Basic Research Program of China(2014CB046400)
文摘Analysis as well as application of ultra-high pressure hydraulic system and elements has become a trend.The structure and operation principle of a new type of ultra-high pressure pipe joint is introduced.The structure of the new type of ultra-high pressure pipe joint is simple and is easy to be produced.The finite element model on two working conditions(preload condition with 30 N·m torque and static-loading condition with 70 MPa pressure)is built and computed.The width of contact area,the equivalent stress status,as well as the contact pressure status are plotted and analyzed.According to the national standard,test on air-tightness,blasting,and cyclic endurance is conducted and the results show that the new type of ultra-high pressure pipe joint has the sealability for ultra-high pressure up to 70 MPa,and the DN6 ultra-high pressure pipe joint can provide effective seal under70 MPa fluid pressure.The research can provide a thinking and method on designing ultra-high pressure pipe joint and push forward the development of ultra-high pressure hydraulic system.
基金This research is supported by Scientific Research Starting Project of SWPU(No.2017QHZ012)Major Project by Education Office of Sichuan Province(No.17ZA0418)+1 种基金supported by the Natural Science Fund for Outstanding Youth Science Fund(Grant No.51222406)Scientific Research Innovation Team Project of Sichuan Colleges and Universities(2017TD0014).
文摘Double shoulder drill pipe joint(DSJ)is a novel thread structure which appears in recent years.Its strength reduced efficiently while the structure design is not appropriately,for the DSJ’s mechanical behaviors weren’t well studied.In this paper a 3D whole structure finite element model of DSJ was established based on the Principle of Virtual Work,and validated the model’s computing results by experimental results.The authors analyzed the stress and strain distribution with the 3D whole structure finite element model’s computing results under torque moment,compression force,tension load,and bend moment.And then acquired the DSJ’s mechanical behaviors under each load.The research works of this paper refer accordance to recognize and design the DSJ.
文摘The out-of-plane distortion induced in a multi-pass circumferential fillet welding of tube to pipe under different weld sequences and directions was studied using Finite Element Method(FEM) based Sysweld software and verified experimentally. The FEM analyses consisted of thermal and mechanical analyses.Thermal analysis was validated with experimental transient temperature measurements. In the mechanical analysis, three different weld sequences and directions were considered to understand the mechanism of out-of-plane distortion in the tube to pipe T-joints. It was learnt that the welding direction plays a major role in minimizing the out-of-plane distortion. Further, during circumferential fillet welding of the tube to pipe component, the out-of-plane distortion generated in the x direction was primarily influenced by heat input due to the start and stop points, whereas the distortion in the z direction was influenced by time lag and welding direction. The FEM predicted distortion was compared with experimental measurements and the mechanism of out-of-plane distortion was confirmed.
