In the test, internal inlay drip irrigation pipes with different wal thicknesses or diameters （￠at 12 mm and 16 mm） were tested under varying tension forces and it was concluded that 90 N is the rational one. What...In the test, internal inlay drip irrigation pipes with different wal thicknesses or diameters （￠at 12 mm and 16 mm） were tested under varying tension forces and it was concluded that 90 N is the rational one. What’s more, the smal er drip-irrigation inner diameter, the thinner wal thickness, and the higher tension force, the lower acceptability, and the larger drip-irrigation inner diameter, the thicker wal thickness, and the lower tension force, the higher acceptability. The causes were analyzed in the research, including manufacturing technique leading to disqualifica-tion and different specifications with the same demands on techniques, and inadap-tation to tension force at 130 N.展开更多
With mean yield（MY）criterion,an analytical solution of the collapse load for a defect-free pipe elbow under internal pressure is first obtained.It is a function of ratio of thickness to radius t0/r0,strain hardening...With mean yield（MY）criterion,an analytical solution of the collapse load for a defect-free pipe elbow under internal pressure is first obtained.It is a function of ratio of thickness to radius t0/r0,strain hardening exponent n,curvature influence factor mand ultimate tensile strength.The collapse load increases with the increase of m,and it is the same as the burst pressure of straight pipe if m=1is assumed.The MY-based solution is compared with those based on Tresca,Mises and twin shear stress（TSS）yield criteria,and the comparison indicates that Tresca and twin shear stress yield criteria predict a lower bound and an upper bound to the collapse load respectively.However,the MY-based solution lies just between the TSS and Tresca solutions,and almost has the same precision with the Mises solution.展开更多
文摘In the test, internal inlay drip irrigation pipes with different wal thicknesses or diameters （￠at 12 mm and 16 mm） were tested under varying tension forces and it was concluded that 90 N is the rational one. What’s more, the smal er drip-irrigation inner diameter, the thinner wal thickness, and the higher tension force, the lower acceptability, and the larger drip-irrigation inner diameter, the thicker wal thickness, and the lower tension force, the higher acceptability. The causes were analyzed in the research, including manufacturing technique leading to disqualifica-tion and different specifications with the same demands on techniques, and inadap-tation to tension force at 130 N.
基金Sponsored by National Natural Science Foundation of China(51074052,50734002)
文摘With mean yield（MY）criterion,an analytical solution of the collapse load for a defect-free pipe elbow under internal pressure is first obtained.It is a function of ratio of thickness to radius t0/r0,strain hardening exponent n,curvature influence factor mand ultimate tensile strength.The collapse load increases with the increase of m,and it is the same as the burst pressure of straight pipe if m=1is assumed.The MY-based solution is compared with those based on Tresca,Mises and twin shear stress（TSS）yield criteria,and the comparison indicates that Tresca and twin shear stress yield criteria predict a lower bound and an upper bound to the collapse load respectively.However,the MY-based solution lies just between the TSS and Tresca solutions,and almost has the same precision with the Mises solution.
