Research Of Static Behavior Of Tubular Gap KK-Joints Made Of Square Chord And Circular Braces

ABSTRACT:In recent years, square and circular steel tubes have been widely used in large span truss structures because of excellent performance. As organic component of the whole structure, design of the tube-to-tube connection is an important aspect. At present, the most researches are concentrated on the gap Circular-Hollow-Section、 gap Square-Hollow-Section and some other simple overlap joints. The researches of multi-plane joints are less, especially KK-joints with square and circular hollow sections. So this paper will adopt the method of nonlinear finite element analysis to study on behavior of gap KK-joints failure mechanism and ultimate capacity. It can provide a reliable basis data for the application of such joints in the future projects. It has a great significance. The main content fulfilled is as follows:1. One previous model is built by ABAQUS software and nonlinear finite element analysis on the joint specimens. Make the analysis results compare with the test data of the predecessors’. Through the comparison, it is feasible to use ABAQUS software perform finite element analysis.2. According to previous experience, suitable. factors that influence joints ultimate capacity are chosen, including element selection、boundary conditions of chord and brace end、loading mode、iterative method of ultimate capacity and so on. A series of gap KK-joints are established.3. Through checking the results of the finite element analysis, the failure mechanism, the characteristics of plastic development and deformation of KK-joints are obtained. Based on the analysis of ultimate capacity and load-displacement curves of joints, the effect of geometric parameters (β、γ、ι、φ、θ、go、gt) action on the static performance of gap KK-joints are summed up one by one. Some strengthening solutions are suggested for the usual failure mechanism.4. Then, through the multi-parameter regressive analysis one formula is presented. The formula is checked by the FE method and has a better accuracy. It can be good to estimate the gap KK-joints’ ultimate load and can be as a reference for engineering design.Finally, the conclusions and the issues will be further researched are summarized.