基于等温面法的发动机活塞裙预锻模优化设计

Optimized design on pre-forging die of engine piston skirt based on isothermal surface method

为了改善预锻模开发设计周期长、成本高、依赖经验的问题,根据材料流动与热量传输的相似性原则,提出采用等温面法对预锻模进行优化设计。以柴油机活塞裙锻件为例,介绍了基于等温面法的预锻模设计过程,并选取了3、5、8和10℃的等温面进行模具设计和有限元分析。首先在ANSYS WORKBENCH软件温度场分析的基础上获得等温面,然后在Geomagic Studio软件中对等温面点云进行拟合,并在UG软件中设计出预锻模具,最后采用DEFORM软件模拟获得型腔填充率、最大锻造压力、等效应变分布和流线形状等,评估不同预锻模具方案的优缺点。结果表明:以8℃等温面为基础设计预锻模具,生产的锻件填充率高、最大锻造压力小,且磁粉探伤未发现开裂缺陷,锻件表面质量良好,满足生产要求。

In order to improve the problems of long development and design cycle,high cost and reliance on experience for the pre-forging die,according to the similarity principle of material flow and heat transfer,a isothermal surface method for pre-forging die optimal design was proposed.Then,for the diesel engine piston skirt forgings,the pre-forging die design process based on the isothermal surface method was introduced,and the isothermal surfaces of 3,5,8 and 10 were selected for the die design and finite element analysis.Firstly,the i-sothermal surface was obtained based on the temperature field analysis by software ANSYS WORKBENCH.Then,the point cloud of the iso-thermal surface was fitted by software Geomagic Studio,and the pre-forging die was designed by software UG.Finally,the cavity flling rate,the maximum forging pressure,the distribution of equivalent strain and the streamline shape were obtained by software DEFORM simulation to evaluate the advantages and disadvantages of different pre-forging schemes.The results show that when the pre-forging die is designed ac-cording to the 8℃isothermal surface,the produced forgings have a high filling rate and a low maximum forging pressure,no cracking de-fects are found by magnetic powder inspection,and the surface quality of forgings is good,which meets the requirement of production.