The Nonlinear Analysis On The Steel Tubular Lap K-joint Ultimate Bearing Capacity

Space structure is one of the popular structures. During the past twenty years, Space structure has been achieved favorable technological and economic benefits. Steel tubular structure has achieved the important position of the application and development of the space steel structures. A steel tubular intersecting joint is one of the main joints in steel tube structures. Therefore, There are very important theoretical and practical value on study and analysis of the directly welded tubular connections.The directly welded tubular K-joint has many influential factors. Their stress conditions are more complex. The theoretical and experimental researches are very important. The length change of lap affect the ultimate bearing capacity of steel tubular K-joint. The paper introduced the nonlinear finite element theory on joint. On the basis of the mode tests of K- joints with large size and full scale ,A four-node shell element in ANSYS is employed to simulate the joints in the analysis. The ultimate bearing capacity of the tubular K-joint is investigated numerically by using the finite element method and close reference to material and geometrical nonlinear properties. The effect of the length of lap on its behavior and ultimate strength is investigated theoretically in the paper. On the basis of analysis on the lap, The influential factors on the lap K-joint are studied in the paper. The studies show the joint failure mechajnism , the distribution of stress, plastic-zones and the deformation of the tubular lap K-points. The bearing capacity in the code is achieved. The results are compared with strength formation. A reasonable formula of ultimate bearing capacity of the lap K-joint is presented, The measurements are put forward to improve the ultimate bearing capacity of the joint. Some useful conclusions are suggested for construction projects.