Refined Finite Element Analysis On Spatial Structure Taking The Welidng Effects Into Consideration

The large span spatial structures have some outstanding advantages of light weight,rational load-bearing capacity, attractive appearance. Large span spatial structures haveobtained widespread application in our country. The reticulated shell and pip trussstructure are two kinds of commonly used structure form in large span spatial structures.The connection is the key to built-up members. Welding is a convenient and low-costway to connect members, so the welding connection is widely used in real project.During the soldering process, large amount of energy are input by heat source, lead tothe non-uniform temperature distribution and produced a large residual stress anddeformation in welded structures. The existence of the stress and the deformation doharm to the stability of the structure, machining precision and the local and globalstability of the structure.Therefore, this article used numerical method to simulate of welding process of thereticulated shell and pip truss structure and provide a reasonable reference for predictingand considering the influence of residual stress on structure bearing capacity in realproject.In order to achieve the research objects, this paper adopted the refinementmodeling method to establishing the calculation model of the steel tubular intersectionjoints and welded hollow spherical joints use the heat generation rate as heat source.Finally, the dynamic changing process of stress and temperature during the solderingprocess are worked out. The residual stress distribution is given. The eventuallycalculation results show that the residual stress near the welding line is close to thematerial yield stress.In order to reduce calculation amount, the solid-beam multiscale finite elementmodel of the K6（2）reticulated shell and pip truss structure were established by usingthe method of multipoint constraints method. The calculation results of multiscale finiteelement models are compared with results of shell model. The eventually calculationresults verify the effectiveness of the multiscale finite element modeIn order to consider the effect of residual stress, solid-beam multiscale finiteelement model of pip truss structure is applied the initial load which is calculated bywelding simulation. The eventually calculation results show that the welding residualstress lead to11.8%reduction of bearing capacity of the pip truss structure.Using the above method to analyze K6（2）reticulated shell, As a results of theexistence of the ball node, the member of the reticulated yielded at first and lead to the destruction of the structure. The bearing capacity of K6（2）reticulated shell was notaffected by the welding residual stress.