Structure Design And Optimization Of Aluminum Alloy Door Based On Die Casting Process

The door is an important part of the car covering.Traditional door manufacturing using stamping-welding process,mold development time is long,production efficiency is low.In order to reduce the process steps,improve production efficiency and reduce production cost,the new structure design and optimization of the car door adapt to the die casting process are carried out in this thesis.Through pressure casting "high pressure,high flow rate" work characteristics to obtain high quality aluminum alloy door plate.based on the traditional stamping and welding door structure,according to the large die casting design code and door design code,the door structure is improved.On this basis,the structure of the door was optimized to meet the requirements of mechanical properties.The assembly surface of the door accessories was changed from the inside door plate to the outside door plate,which reduced the weight of the door and met the requirements of strength and stiffness.Finally,the die casting of the aluminum alloy door was simulated and verified.The main research contents are as follows:(1)The inner plate and outer plate of an existing stamping and welding process door(left rear door)were improved.According to the function of the door,the surface features of the inner plate were retained.At the same time,according to the design specification of casting parts,the door plate was designed as casting parts,and the surface features of the assembly surface of the door accessories were transferred to the outer plate.In order to improve the stiffness of the door,a cross-type door inner plate structure is referred to as the inner plate of the car door.According to the design criteria of the door plate,combined with the design criteria of die casting and door strength requirements,most of the reinforcing parts or reinforcing structures in the ram-welded door plate are integrated into the door plate die casting in the way of increasing the thickness.In the second part,the die casting system of the aluminum alloy door casting parts is designed.According to the casting process experience and theoretical formula,the size of the runner and the position of the gate are calculated,and the die casting machine which can complete the casting task theoretically is calculated.(2)The die flow analysis of the designed die casting was carried out by Pro CAST,and the unreasonable features in the design were redesigned.the finite element software Hyper Works is used to analyze and optimize the stiffness of the door.The stiffness analysis and modal shape analysis were carried out by Optistruct solver in Hyper Works software.The door thickness is optimized by size optimization to achieve the optimal thickness;Meanwhile,combining with the design principle of casting reinforcement,the shape and position of reinforcement bars with the same flow direction as metal solution were calculated.(3)After the optimization design,the model was reconstructed and the mechanical properties of the door were analyzed.the die cast aluminum door was simulated to verify whether the filling and solidification process is reasonable.The size and position of the overflow groove were adjusted,and the die casting speed,die temperature and die casting temperature were simulated as variables.Orthogonal experiments were designed to determine the optimal working parameters of the casting system with the loose shrinkage cavity area as the target,and the filling process,solidification process and loose shrinkage cavity rate of the casting were analyzed.