The hydraulic bulging technology of tubes can provide hollow parts with special-shaped cross sections. Its manufacturing process can effectively improve material utilization and product accuracy and reduce the number and cost of molds. However, the hydraulic bulging process of parts is very complicated. The size of the tube blank, the design of the loading route, and the forming process parameters will have an effect on the molding quality. Closed tubular torsion automobile beam is considered as the research object to study hydraulic bulging die design and optimize forming process parameters. CATIA software is used to design torsion beam product structure and hydraulic bulging die. AMESim software is employed to design hydraulic synchronous control system for cylinders on both sides of the hydraulic bulging die. Mathematical control model is established and verified in Simulink software. DYNAFORM software is applied to conduct numerical simulation of hydraulic expansion. The supporting pressure, molding pressure, friction coefficient, and feeding quantity are taken as orthogonal experiment level factors. Maximum thinning and maximum thickening rates are taken as hydraulic pressure expansion evaluation indexes to complete the orthogonal experiments. Main molding process parameters are analyzed via orthogonal experiment results and optimized by employing the Taguchi method. Optimal hydraulic bulging parameters are obtained as follows: supporting pressure of 20 MPa, molding pressure of 150 MPa, feeding quantity of 25 mm, and friction coefficient of 0.075. Simulation analysis results indicate that the maximum thinning rate is equal to 9.013%, while the maximum thickening rate is equal to 16.523%. Finally, the design of hydraulic bulging die for torsion beam was completed, and its forming process parameters were optimized.

Numerical simulation of the injection molding of the inner panel of the car door and the optimization of its process parameters were completed. The inner panel and its injection mold were designed by UG software and simulated by the filling and cooling module of the Moldflow software. Different gate schemes were selected to compare quality indicators such as filling time, air pockets, and weld lines to obtain the optimal number of gates. We established the objective function model with gate position as the independent variable, and used a multi-population genetic algorithm to solve the optimal position of the function model to get the best gate position. The mold temperature, melt temperature, cooling time, holding pressure, and holding time were selected as the influencing factors, and volume shrinkage and warpage deformation were selected as the evaluation indicators to design and complete the orthogonal test. The test data were simulated by Moldflow, and the optimal combination of process parameters was determined by range and variance analysis. The BP neural network model related to the molding process parameters, volume shrinkage, and warpage deformation was built, and the trained network model was optimized with the ant colony algorithm. The optimal parameter combination was: mold temperature 76 ° C , melt temperature 205 ° C , cooling time 23.8s, holding pressure 54.7Mpa, and holding time 22.1s. The simulation results showed that volume shrinkage was 13.32% and warpage deformation was 4.315 mm. The design of an injection mold for the car door inner panel was completed and its molding process parameters were optimized.

Aiming at the problem of the wear caused by the mutual movement between the convex die and the sheet material in the stamping process, which results in a decrease in the die service life. In the paper, the three-dimensional design of the drawing die for the outer plate of the rear wheel cover was carried out by using UG, the simulation of the die stamping process was carried out by using Deform-3D, the main wear positions of the die were determined, the four process parameters of die clearance, friction coefficient, stamping speed and die hardness were selected as the test factors, the amount of die wear was used as the evaluation index to establish an orthogonal test, the multiple linear regression analysis of the test results was carried out by using SPSS software, and the empirical formula for the surface wear of the drawing die was established. Finally, the BP neural network model between process parameters and wear amount was constructed using MATLAB. The weights and thresholds of the nodes in the implicit layer of the model were optimized by using the whale algorithm to obtain the optimal combination of process parameters with minimum wear amount predicted based on the optimized WOA-BP neural network model. The minimum wear amount of the optimized convex die was 1.02×10-6 mm. The optimal combination of process parameters was friction coefficient 0.12, stamping speed 22mm/s, die hardness 62HRC, and die clearance 0.88mm, which completes the design of the automotive rear wheel cover outer plate drawing die and optimizes its surface wear process parameters.

The hydraulic bulging technology of tubes can provide hollow parts with special-shaped cross-sections. Its manufacturing process can effectively improve material utilization and product accuracy, and reduce the number and cost of molds. However, The design of hydraulic bulging die, especially the design of hydraulic system, is more complicated. The synchronization of the hydraulic system and the response of the system will affect the forming quality of parts. Aiming at the research of hydraulic system design and synchronous characteristics of hydraulic expansion mold of automobile torsion beam, this paper takes a hydraulic expansion mold of automobile closed torsion beam as the research object, CATIA software is used to design the structure of torsion beam products, and then the process loading route of parts processing is determined. Auto torsion beam hydraulic pressure expansion mould structure is designed, in view of the synchronization requirements on both sides of the hydraulic cylinder, design a new automatic correction of overhead cylinder hydraulic synchronous system, AMESIM is used to get two cylinder piston rod synchronous displacement curve, the system can adjust the bidirectional shunt follow up valve to realize the automatic adjustment function is validated, synchronization system mathematical model is established, The transfer function of the closed-loop control system is pushed to, and SIMULINK is used for simulation analysis of the system, the step response curve of the system is successfully obtained, which proves that the system performance is good, and the characteristics of the synchronization system of the overhead cylinder of the hydraulic expansion mold of the torsion beam are analyzed.