FEM Analysis Of The Welding Residual Stress And Temperature Deformation About Stadium Canopy

With the development of the large buildings, the super demand on the technical quality of the steel structure has been proposed. Welding residual stress is an important factor for effort the quality of the structure at the construction site; control deformation of structural is the necessary condition to ensure its'normal work in service process of the structure. Therefore, it is important thing to reduce welding residual stress, predict and control the deformation of the structure.In this paper, welding residual stress of the stadium and deformation of the stadium with environmental temperature were researched. Based on the principles of heat transfer and thermal elastic-plastic theory, the nonlinear finite element analysis software ABAQUS was used. Three-dimensional finite element analysis model of the welded steel pipe intersection and stadium canopy was established. The temperature field of the welded steel pipe intersection was calculated, the distribution of equivalent residual stress and equivalent strain was studied.The effort of welded residual stress under different technological parameter was analyzed, and the better process program was obtained. The vertical displacement of the stadium canopy under the environmental temperature change was calculated.It can be obtained from the simulation: after welded a certain time, the high temperature shape was stabilized and moves forward entirely; the equivalent residual stress on the weld is large and may exceed the yield limit; along the circumferential of weld, the equivalent residual stress maintains in the yield limit , but fluctuate at the start arc point; along the radial of weld, there is a peak value of equivalent residual stress in the middle of the weld, and the equivalent residual stress declines rapidly near the weld of steel pipe; from the surface to the end, equivalent residual stress of single-layer welding decreased gradually in the weld depth. Equivalent plastic strain distribution was relatively stable, there is a peak value of equivalent residual strain in the middle of the weld, and the equivalent residual strain declines rapidly by both sides, and gradually reduced to zero. Welding speed and arc welding residual positions are two important factors of effecting residual stress. Compared various welding residual stress of the programs, the residual stress can be further reduced after welding, when it is welded from the middle position the two sides of intersecting lines weld, heated to above 190℃, add heat about 8 .267×10~9J per cubic meter and to 6 mm /swelding speed welding. the vertical displacement is large under the environmental temperature difference;when temperature increases, two main arches are upward; and when temperature decreases, the two main arches are downward; the vertical displacement of the structure will have a bigger change when the temperature declining than increasing. The maximum of vertical displacement under temperature decreasing is approximately twice as many as under declining.