内置颗粒减振器的机床刀具减振分析

机械加工中刀具的振动对工件加工质量有很大影响,内置颗粒阻尼减振器会对刀具起到较好的减振作用。颗粒减振器通过在有限封闭空间中填充微小颗粒达到减振目的。安装有颗粒减振器的刀具是典型的刚散耦合系统,刚体和散体之间相互耦合作用是研究减振机制的关键。应用离散单元法对内装颗粒减振刀具进行建模,利用集合平均计算所有内装散体颗粒对外部振动刀具的接触作用力,在离散单元法应用软件进行二次开发实现刚散耦合建模。利用耦合程序进行仿真分析,通过幅频特性曲线中最大峰值降低比和等效阻尼比来衡量减振效果,研究减振颗粒的材质、粒度、填充率参数对减振效果的影响。结果表明:同样数量时颗粒密度越大减振效果越好;同等质量时颗粒粒度在5~6 mm之间减振效果较好;颗粒填充率为12.5%时减振效果最优。

Damping Performance Analysis for Machine Tools with Particle Vibration Damper

The vibration of machine tool has large effect on the quality of the part surface. The machine tools with particle vibration damper have good damping performance. Particle vibration damper is filled with little particles to decrease vibration. The machine tool with particle vibration damper is a typical rigid-bulk coupling system. Rigid-bulk coupling is the key to analyze damping mechanism. DEM was used to model bulk of particles system; the contact forces of total particles were calculated average and then applied on the vibrating rigid body. PFC program secondary developing was used to model particle vibration damper with rigid-bulk coupling. Using the rigid-bulk coupling programs, the effect of particle parameters on damping performance, such as density, size and filling ratio of particles, were simulated. The max amplitude decreasing ratio and the equivalent damping ratio were used to indicate the damping performance of particle vibration damper. The results show that the damping performance is better when the density of particles with same quantity is larger, it is better with 5~6 mm diameter of particle, and it is optimal with 12.5% filling ratio.