基于断裂力学的蜂窝芯超声切削过程分析

Analysis of Ultrasonic Cutting Process of Honeycomb Core Based on Fracture Mechanics

针对尖形刀切削Nomex蜂窝芯振动加工参数难以选取等问题,从实际加工工艺出发,构建了尖形刀前倾超声切削蜂窝芯材的运动学方程,并利用脆性断裂力学理论建立了在不同超声振幅进给分量条件下材料在断续、连续两种变形破坏形式下的切削动态应力模型。基于断续变形破坏应力模型的数值仿真预测了振动及加工参数对切削力影响规律,并进行了尖形刀超声振动切削试验,试验数据表明,切削力随超声振幅、刀具前倾角的增大而增大,随进给速度的增大而减小,通过对比试验得出超声振幅进给分量对切削力影响较大,实验结果与理论推导结论一致,证明了切削动态应力理论模型的有效性与合理性。

Aiming at the problem that it is difficult to select the vibration processing parameters of the Nomex honeycomb core cutting with a pointed blade,based on the actual processing technology,a kinematic equation for the forward cutting of a honeycomb core material with a pointed blade is constructed.Cutting dynamic stress model under the condition of amplitude feed component under intermittent and continuous deformation and failure modes.The numerical simulation based on the intermittent deformation failure stress model predicts the influence of vibration and machining parameters on the cutting force,and a cutting test of ultrasonic vibration of a sharp knife is performed.The test data shows that the cutting force increases with the increase of the ultrasonic amplitude and the forward rake angle of the tool.It increases and decreases with the increase of the feed rate.It is found through the comparative test that the ultrasonic amplitude feed component has a greater effect on the cutting force.The experimental results are consistent with the theoretical derivation.It proves that the theoretical model of cutting dynamic stress is effective and rationality.