垫板加强X形圆钢管相贯节点滞回性能研究OA

Cyclic cavity expansion model(CVGM)was compiled with Fortran language and embedded into the VUSDFLD subroutine in ABAQUS software.Finite element simulation was carried out for the N-shaped circular steel tube intersecting joints and the N-shaped circular steel tube intersecting joints strengthened with backing plates.Compared with the test results,it was found that the finite element simulation was in good agreement with the test results,which verified the feasibility of using CVGM model to predict the fracture behavior of the plane circular steel tube intersecting joints and the plane circular steel tube intersecting joints strengthened with backing plates.In addition,18 X-shaped circular steel tube intersecting joints and 18 X-shaped circular steel tube intersecting joints strengthened with backing plates were modeled.The CVGM model was used to predict the fracture of the 18 joints,and the hysteresis behavior of the joints under various parameters was studied.The results show that compared with the unreinforced joint,the ultimate bearing capacity of the strengthened joint is increased by 37.5%～56.9%,and the ultimate displacement is reduced by 4.4%～20.3%.The ductility of the strengthened joint is lower than that of the unreinforced joint.The ultimate bearing capacity and stiffness of the joint increase,but the ultimate displacement and ductility decrease with the increase of the outer diameter ratio β of the branch pipe,the thickness of the backing plate tp and the width of the backing plate B.With the increase of backing plate length L and weld size hf of weld leg,the ultimate bearing capacity,ultimate displacement,rigidity and ductility of the joint will increase.With the increase of main pipe diameter-to-thickness ratio γ,the hysteresis performance of each joint decreases.