Optimization Of Hydroforming Process Parameters And Characteristics Of Bellows In Rocket Tank

The bellows of rocket storage tank is an important part of pressurized conveying pipeline system,which mainly plays the role of isolating oxidant and combustor.In the current manufacturing process,bending and welding are mainly adopted.,which has some problems,such as poor forming accuracy,difficult welding and many forming defects.In order to solve the problems existing in the existing process,a new production process scheme was proposed.The completed work is as follows:Taking a new type of Rocket Tank bellows under design as the research object,the hydroforming process was proposed to replace the existing process scheme,the hydroforming simulation model of this type of bellows was established,and the process parameters calculated by empirical formula were simulated.By analyzing the simulation results,the effects of bellows rebound and ripple position on waveform parameters were studied.The hydroforming experiment was carried out according to the simulation model,and the difference between the experimental and simulation results was analyzed.The destructive experiment of bellows hydroforming was carried out,and the forming limit of this type of bellows was tested,which provided a reference for subsequent parameter optimization.Using the single factor method,the effects of the changes of forming pressure,die axial feed,single wave development length and die fillet radius on the waveform parameters of bellows were analyzed.In order to obtain the bellows with target waveform parameters,the general value range of several process parameters was estimated.The experimental scheme was arranged by BBD(Box-Behnken Design)experimental design,and the influence of coupling of various process parameters on the waveform parameters of bellows was analyzed by response surface method.The display expression between hydroforming quality index and process parameters was established.Through response surface optimization,a number of satisfactory combinations of process parameters were obtained and verified by experiments.The results showed that the test values were close to the predicted values of response surface,and met the design and production requirements.The external pressure check simulation and experiment of the bellows produced by hydroforming process were carried out.The results showed that the bellows produced by hydroforming process met the design and application requirements.