Optimization Study On Welding Sequence Of Side Beam Of Welded Frame In 200km/h High-speed Powered Car Train-set

Because of the unbalanced heating/cooling during welding process, these components welded inevitably produce the residual deformations that should not be neglected. The welding residual deformation is the crucial influential factor in the design integrality, the rational manufacturing techniques and the service durability of welding structures. But deformation rectification after welding is expensive and liable to impair the service durability. So the scientific and quantitative predicting of welding deformation regularities and then controlling welding deformation, there will be important engineering significance to guide manufacturing technique of welding.The heating-elastic-plastic simulation model based on heating-mechanical coupling algorithm is used against the welding process essential in this thesis and the segmented moving point heating source whose efficiency is higher is used to simulate welding heating source and a number of strategies in establishing the complex models are also presented to normalize mechanical boundaries, thermal boundaries, initial boundary conditions, geometric boundaries and material properties. Besides above those strategies, under ensuring the precision of calculation, the bigger elements are adopted to reduce time of calculation, so this model can improve the efficiency, which is a key to analyze the side beam of the frame model.Reducing box beam can use the two ways of structure design and welding technique, under the same structure design, there are several methods, for example, adjusting welding sequence, changing heat flux input and so on. Adjusting welding sequence method is adopted in this thesis, because adjusting welding sequence have a lot of advantage, for instance it can be carried easily in practice, its cost is lower than others and welding sequence adjusted of side beam is more because it has many welding joint.Therefore, simulation research of welding distortion of side beam is done by adjusting welding sequence firstly, then rules of welding distortion changing is found, as a result, the optimizing scheme of welding process is put forward though comparison for different welding residual distortion, these supply a new choice for guiding manufacturing technique of welding.