Optimization Design Of Integrated Casting Car Door Body

Car door body as an important part of the car,its lightweight research has been the focus of the automotive industry.In this paper,the integrated forming of car door body is studied from three aspects:structure,property,wax making technology and casting technology.The main research contents and achievements are as follows:Firstly,the structure and performance of the car door were simulated,and the Hyper Mesh software was used for geometric processing and mesh division of the car door model.Then the finite element software ANSYS is used to simulate the modal,stiffness and strength of the car door body.The modal analysis of the first natural mode of the car door body is 190.13Hz,which is greater than the excitation frequency of the car 25Hz,so the car door body can avoid resonance with the vibration source;The stiffness simulation results show that the maximum displacement of the car door body is2.5244mm under the two conditions of the sinking stiffness,and the sinking stiffness is291.67N/mm,indicating that the model meets the requirements of the sinking stiffness.In the analysis of torsional stiffness,the maximum displacement of torsional stiffness is 1.3981mm,which meets the requirements of torsional stiffness.The strength simulation results show that the maximum displacements are 32.006mm,42.887mm and99.625mm respectively under three working conditions.In line with national standards.Secondly,the software Moldflow is used to design the wax process of car door system.Firstly,the model of car door body is repaired,simplified and meshed.The best gate scheme was analyzed by selecting medium temperature liquid wax material.Four gate schemes were designed and six internal gate schemes were determined as the best by simulation analysis.Then,the wax injection system design and process parameters optimization,finally get the best wax injection process parameters,melt temperature60?,mold temperature 23?,wax injection time 12s,pressure holding time 32s,the wax mold volume shrinkage is the smallest.Then,a gravity investment casting process suitable for the structural characteristics of the car door body was designed.The finite element software was used to simulate the process and analyze the distribution of defects in the mold filling process,solidification process and shrinkage cavity and porosity.The simulation results show that the shrinkage cavity and porosity in the interior of the car door body mainly exist at the joints of the stiffeners of the car door body,with a total volume of 28.377cm~3.These defects are mainly caused by the long solidification time of the hot joints and the lack of feeding.According to the simulation results of the initial scheme,the gating system was optimized,and the inner runner was added to the corresponding node position,and several auxiliary runner were added to feed the hot node position.The simulation results show that the defects in the casting are reduced to 7.6725cm~3.Finally,in order to further optimize the casting process scheme of car door body,this topic designed the low-pressure investment casting process scheme,and carried out simulation.The simulation results show that the low-pressure investment casting is better than gravity investment casting.The process scheme and parameters of low pressure investment casting were optimized.The shrinkage cavity defect in the car door is reduced to 4.896cm~3.The shrinkage cavity and porosity in the key parts of the car door body are eliminated and the quality of the casting is improved.