预应力硬态切削的热力耦合模型及数值模拟

Coupled Thermo-Mechanical Model and Numerical Simulation of Pre-Stress Hard Cutting

基于预应力切削原理,分析了工件材料的本构关系、刀屑接触面的摩擦模型以及热控制方程等切削模拟中的关键技术.采用任意拉格朗日-欧拉方法(ALE)和网格自适应技术实现了切屑的分离,建立了预应力切削的三维热力耦合有限元模型.对轴承套圈的预应力硬态切削过程进行了模拟,获得了不同预应力条件下的切削力、切削温度和已加工表面残余应力的分布规律,并与实验数据进行了比较和分析.结果表明,两者具有较好的一致性.

One droplet per pulse is the most ideal mode of droplet transfer for pulsed metal active gas （MAG） welding. In order to meet the requirements of this transfer mode, this paper adopts constant peak and base phases to implement the current external characteristics, and uses the pulse frequency modulation （PFM） combined with the high-frequency inverter and the DSP digital control to adjust the average current and to further control the melting velocity of the welding wire. Thus, the difficulty in the arc length control is overcome. Experimental results indicate that the PFM-based average current modulation implements the droplet transfer control of pulsed MAG welding with high stability and good welding quality.