Study On Mechanical Performance Of New Assembly Type Concrete-Filled Steel Tubular Lattice Wind Tower Joint

In recent years,the concrete-filled steel tube lattice tower has been paid attention and researched by many experts and scholars at home and abroad.It has been found that there are problems such as high construction accuracy requirements and high welding difficulty during on-site construction.Therefore,this paper proposes a new type of assembly node for the concrete-filled steel tube lattice wind power tower,which realizes the factory production of the tower node,reduces the difficulty of on-site welding construction,optimizes the force condition of the node area,and improves the bearing capacity of the tower node,In line with the concept of prefabricated buildings in the new era.In this paper,five scale models of the node are made,and the static loading method is adopted,combined with the test data and the finite element simulation software ABAQUS,and the following conclusions are drawn:In this paper,the test is carried out with the parameters of the web member wall thickness of the fabricated joint,the thickness of the wrapping plate,and the setting of the stiffening plate,to explore the joint bearing capacity,failure mode,deformation capacity,and core area stress distribution law.The test results show that the failure mode of the specimen is divided into two types: the buckling of the compressed web and the plastic failure of the wrapped plate in the tensile zone,and the wrapped plate can avoid the punching shear failure of the tower column tube wall.The elasto-plastic stage of the load-deformation curve of the specimen is longer,and the deformation of the web member of the specimen is more coordinated with the force,indicating that the joints have strong deformability.The wall thickness ratio of the web member and the wrapped plate increased from 0.67 to 1,and the ultimate bearing capacity of the specimen was increased by 40.1%,but the deformation capacity of the joint was reduced by 29%,indicating that it is effective to control the ultimate bearing capacity of the joint by increasing the thickness of the web member.However,the deformability of the specimen will be reduced.Compared with the specimens without stiffening plates,the ultimate bearing capacity of the specimens with stiffening plates is increased by 38%,and the deformation capacity of the specimens is increased by 71%,which can effectively reduce the stress concentration of the web members.Therefore,stiffening plates can be used in engineering design to reduce the influence of stress concentration on the bearing capacity of web members.On the basis of experimental research,the finite element analysis and research on the fabricated joints are carried out.By comparing with the test results,the accuracy of the finite element simulation was verified,and then a large number of parameter analyses were done on the new fabricated joints,and the influence of each parameter on the bearing capacity and failure modes of the joints was studied.The finite element study shows that the thickness ratio β of the web member and the wrapped plate has a significant effect on the failure mode of the joint: β is less than 1.25,and the failure mode of the specimen is the buckling of the compressed web member.When β is greater than 1.25,the failure mode of the specimen is plastic failure in the tension zone of the wrapped plate.When the wall thickness ratio γ of the web member to the stiffening plate is less than 1.1,the ultimate bearing capacity of the specimen will not change much when γ increases,and the specimen still suffers from the buckling failure of the compressed web member.When γ is greater than 1.1 and less than 2.67,the increase of γ has a significant influence on the ultimate bearing capacity of the joint.When γ is greater than 2.67,the increase in the thickness of the stiffener has no obvious influence on the ultimate bearing capacity of the specimen.At this time,the failure mode of the specimen is the buckling failure of the compressed web.It is suggested that when designing new fabricated joints,the wall thickness ratios of web members and wrapping plates,web members and stiffening plates should be controlled within a reasonable range of values.