Research On Mechanical Properties And Design Method Of Double Layer Aluminum Alloy Gusset Joints

Aluminum alloy is being increasingly used in large-span spatial structures due to its light weight,strong corrosion resistance,high strength,and easy extrusion molding.The gusset-type joint(GJ)system is an important joint method in aluminum alloy spatial structures.This system was developed by Temcor Company(the United States)and comprises plates,rods,and bolts.Gusset-type joint consists of single-layer and double-layers.A total of 7500 completed projects currently use the gusset-type joint system,which is mainly distributed in 75 countries.Existing studies on the mechanical properties of aluminum alloy GJs(AAGJ)are mainly focused on single-layer AAGJs.By contrast,the mechanical properties of double-layer AAGJs remain unexplored.The main research contents and achievements are as follows:(1)In this research,the flexural behavior of single-and double-layer AAGJs were experimentally studied through eight full-scale joint tests.The failure mode,rigidity,internal stress distribution,stress transmission mode,and ultimate bearing capacity of the tested joints were determined.Contrast analyses between the in-plane and out-of-plane flexural behaviors of a single-layer joint were performed.The same analysis was conducted between the flexural behaviors of GJs with Huck and stainless steel bolts and between those of single-layer and double-layer GJs.The research shows that the out-of-plane flexural rigidity of double-layer GJ is 2.61 times that of single-layer GJ.(2)An effective and reasonable finite element simulation method was established by using ABAQUS software,which was verified by the test results.Furthermore,the effects of the parameters such as the thickness of plates,the thickness of the flange,the thickness of the web,and the height of the H-shaped rods on the ultimate bearing capacity of AAGJs were studied through parametric modeling,which provided data basis for the study of the calculation method for the ultimate bearing capacity of AAGJs.(3)On the basis of the above experimental research and finite element analysis,a simplified calculation method for bearing capacity of single-layer and double-layers AAGJs was put forward through theoretical analysis,which can provide theoretical basis for practical engineering and engineering design.