Design And Analysis Of The Welding Inner Support Mould Mechanism For Tank

Friction stir welding of aluminum alloy is easy to obtain high-quality welds,which has become one of the main technical means of rocket tank welding assembly.At present,the tank of launch vehicles in China is mainly produced by horizontal assembly welding technology and equipment.With the development of the aerospace industry,there is a demand for new vertical assembly welding technologies and equipment,and related research has entered the application stage.There is a common problem between horizontal and vertical stirring welding: there is a significant upset force between the stirring head and the workpiece.Maintaining the stability of the welding process,external pressure and internal support of the mold are the key to ensuring the quality of the weld seam.At present,in the actual production of horizontal assembly welding,the inner support mold is loaded and removed,and on-site manual disassembly of small components,sequential internal and external transfer,assembly,and adjustment operations are used.Existing problems: difficulty in personnel entry and exit,limited operating space,high labor intensity,long time consumption,safety hazards,difficult adjustment,and poor technical stability due to human influence.Therefore,it is necessary to innovate the design of a brand new foldable internal support mechanism mold,which can be integrated or removed from the storage box by changing the structure shape to meet the requirements of practical efficient and high-quality production.According to the different working conditions and gravity conditions of horizontal and vertical friction stir welding,according to the principle of no one or few people intervening,three kinds of folding and expanding inner support mold mechanism configuration schemes were proposed and designed: vertical full-automatic inner support mechanism,vertical semi-automatic inner support mechanism,and horizontal semi-automatic inner support mechanism.And engineering structural design was carried out for three types of internal support molds.The kinematics models of the key mechanism of the vertical welding fully automatic inner support die were established,and the functional relations of the position,speed and acceleration of each component of the mechanism were obtained;Use ADAMS simulation analysis software to simulate the motion of the mechanism and obtain the motion characteristic curves of the output components of the mechanism;Using analytical method,obtain the parameter expression that satisfies the condition of simultaneous radial retraction and simultaneous stop of the correction arc bar on the truss of adjacent branch chain folding mechanism without interference.Based on the kinematics model of the branch chain folding and expanding mechanism,the kinematic error of the branch chain folding and expanding mechanism is analyzed under the condition of considering the error of the rod length and the error of the rotation pair;Sensitivity analysis is carried out on the Error term of each component to explore the influence rule and degree of each error factor on the overall error of the branch chain folding and unfolding mechanism;Simulate error random variables using MATLAB software,and conduct reliability simulation based on the simulated errors.Calculate the shaping force on the tank wall and the pressure exerted by the external pressure mold on the tank wall.Analyze the force on each member of the branch chain folding mechanism of the internal supporting mold based on the shaping force,pressure,and top forging force applied to the tank wall;A finite element analysis model was established for the forced calibration of the storage tank cylinder section and head using ANSYS finite element simulation software.At the same time,the mechanical forces of the internal support mold were analyzed,and the strength and stiffness were verified.