Modeling Of Weld Quality Prediction And Development Of Weld Quality Management System For Large Aerospace Structural Parts

With the development of aerospace industry,new aerospace products posed great challenges to the development and production of tanks.Previously,in the field of welding,due to the aerospace industry in its infancy,the tank only rely on artificial could meet the demand.The industry did not attach importance to how to improve the welding quality and production efficiency of the tank,which to some extent restricted the pace of progress of Chinese aerospace industry.It is of great significance to improve welding efficiency and ensure the quality of welding to establish the welding quality prediction model and introduce the digital management system of welding.Based on the above background,the relationship between the assembly of parts to be welded and the weld quality in the pre-welding stage was studied by this paper.The quality prediction model of friction stir weld of 2219-T6 aluminum alloy was proposed.Firstly,the weld gap,welding torch alignment and welding seam misalignment were selected to characterize the assembly of weldment,and the joint strength and stretch rate were selected to characterize the quality of joint.Response surface method was used to design test plate welding experiment and stretch experiment.Regression analysis was used for experimental data analysis.The regression model was established for the assembly condition of the weldment and the joint strength and stretch rate.Secondly,three random variable sampling methods are designed,which were based on the Monte Carlo important sampling method,and combined with the feature of assembly.On the basis of response surface regression model,the relationship model of welding parts assembly with joint strength and joint tensile rate was simulated respectively,and the probability density model of joint performance was given.Finally,the welded seam management system was developed,and the 3D reconstruction model of weld point cloud was integrated in it,which can introduce the digital management method for the traditional welding field,improve the management efficiency,and lay a data foundation for the later model training system.Weld gap is the key factor affecting joint strength and elongation,and with the increasing of assembly clearance,the performance parameters of the joint will decrease obviously.On the other hand,under the influence of welding torch alignment and welding seam misalignment,the joint performance has an asymmetric deviation.When weld gap is between 0 mm and 2mm,welding torch alignment is between-0.6mm and 0.6mm,welding seam misalignment is betweed-0.3mm and 0.3mm,the joint strength will be between 276 Mpa and 331 Mpa,eaqul to 62.73%-75.23% strength of base metal,and will hava a probability of 68.33% to reach 70% of the base metal strength.The joint stretch rate will be between 3.95% and 6.52%,and will hava a probability of 73% to reach 5.5%.