Research On The Performance Of Cold-formed Thin-walled Single Hole Steel Plate Bearing Components Based On Component Method

Previous studies have shown that cold-formed thin-walled steel plate-bolt joints exhibit typical nonlinear semi-rigid characteristics.The component method has been proved to be an excellent method to study semi-rigid joints.This thesis will first take the cold-formed thin-walled steel plate-bolt connection joints as an object,and divide this joints into basic components through experimental research and theoretical analysis.Next,the behavior of the cold-formed thin-walled single-hole steel plate hole-wall bearing module in the basic components will be studied.In this thesis,the following conclusions are obtained through experimental research and theoretical analysis of 3 full-scale cold-formed thin-walled steel plate-bolt connection joints.1.For cold-formed thin-walled steel plate-bolt connection joints,the basic components of the joint are three: beam bending component in the joint area,beam compression flange component in the joint area,beam web(cold-formed thin-walled steel plate)-bolt connection beam web hole wall bearing component.2.Beam bending component in the joint area has a great influence on the slope of the moment rotation curve of the joint,that is the stiffness of the joint.In order to better evaluate the influence of beam bending components on joint performance,a bending moment transfer ratio coefficient-? is defined in this thesis.On the basis of joint analysis,the bearing components of cold-formed thin-walled single hole steel plate are analyzed independently.In this thesis,48cold-formed thin-walled steel plate bolt connections are tested and analyzed,and the following conclusions are obtained:1.The equations which can accurately fit the actual bearing capacity of components under three failure modes are summarized.2.Based on the deformation of the component and the bearing capacity equation under the corresponding failure mode,the judgment criterion function of the end pull out and bearing failure mode of the component is summarized.3.The small deflection plate theory is introduced to fit the buckling load of the bearing plate area of the component hole wall when buckling occurs.The error between the theoretical value and the test value is within 20%.4.The thickness of the steel plate has a great influence on the buckling load of the bearing plate area of the hole wall.The relationship between buckling load and steel plate thickness is cubic function.5.The test results show that the influence of buckling of the bearing plate area of the hole wall on the bearing capacity of the components cannot be ignored.In this thesis,the maximum difference equation of the influence of buckling on the bearing capacity of components is derived and summarized by theoretical deduction.6.By comparing the experimental value with the theoretical value,this thesis considers that the Eurocode 4 initial stiffness equation can fit the actual component's initial stiffness.In order to describe more accurately the load-displacement curve of the component buckling in the bearing plate region,this thesis introduces a post buckling stiffness parameter.