空间大扭曲叶片拔模路径优化及验证

Optimization and Verification of Drafting Path for Twisted Blades

分体或整体式砂芯铸造是目前大功率液力变矩器叶轮的主要生产方式,整体式砂芯铸造精度高,但需要叶片能够在砂芯成型后拔出.传统的方法为不断进行样件试制和试拔,研发周期长,同时也增加了成本,文章针对整体式砂芯铸造工艺中空间大扭曲叶片拔模问题开展数学建模和样件试验研究,将复杂三维叶片拔模问题简化为空间三维实体无碰撞通过约束空间的数学模型,利用UG/Grip二次开发实现叶片与约束空间的干涉碰撞检测,结合遗传优化算法,以最小干涉体积为优化目标进行叶片拔模性分析,构建空间大扭曲叶片拔模性判别及拔模路径计算模型.通过UG与MATLAB的联合仿真,实现了空间复杂三维叶片拔模性分析及拔模路径计算,研制了相应样件并进行了验证,实现了大扭曲叶片的可制造性评价,成果可为其它需要整体铸造的复杂大扭曲空间实体可制造性分析提供有效技术途径.

At present,separate or integral sand core casting is a popular way to produce impellers of high-power torque converters.During separate sand core casting,the sand core is fragile and needs special tooling for installation and positioning.Therefore the precision of blades made of separate sand core casting is lower than that of integral sand core casting.Integral sand core casting requires the blade to be able to be pulled out after the sand core is formed.Because the blade of a hydraulic torque converter is a twisted solid with complex spatial shape,there is no established software or method to calculate the extraction process.The traditional method is to repeatedly manufacture and draft different samples,leading to a long production cycle and high costs.In this paper,mathematical modeling and sample tests were carried out for the drafting problem of twisted blades in the integral sand core casting process.The complex three-dimensional blade drafting problem was simplified into a mathematical model,where a three-dimensional spatial entity going through a constraint space without collision.UG/Grip is used for interference detection between blades and the corresponding constraint space.The blade drafting process was analyzed with genetic optimization algorithm that set the minimum interference volume as the optimization goal.A discriminant model for the drafting capability and a method for generating the drafting path of big-twisted blades were established.In this study,through UG and MATLAB co-simulation,the analysis of drafting of blades with high spatial complexity are carried out and drafting path generation are realized.The corresponding sample was developed and verified.The manufacturability of integral-casting-made blades was then evaluated.At the same time,it provides a technical support for subsequent automatic drafting of blades.