To solve the problem of instability caused by flutter and vibration in milling tool system,a dynamical model of the tool-fixture system is established with consideration of the influence of internal damping. Based on the characteristic equation of dynamics model,the relationship between internal damping matrix and internal/external damping ratio is deduced. According to the method of eigenvalue real part analysis,the influence of internal damping on system stability and the influence of different coating materials between tool-fixture and the rotational speed on the internal damping of system are obtained. The simulation analysis, random response and modal analysis show that the larger the internal damping is,the more inhibition of the vibration of the system is;the larger the material damping ratio is,the greater the stability of the system is;internal damping and material damping ratio are both related to vibration mode.%针对铣削刀具系统颤振及振动不稳定的问题,建立了考虑内阻尼影响的刀具-夹具系统动力学模型.基于动力学模型的特征方程,推导了内阻尼矩阵与内外阻尼比之间的关系.根据特征值实部分析法,得出内阻尼对系统稳定性的影响和刀具-夹具之间不同涂层材料和转速对系统内阻尼的影响.仿真分析、随机响应和模态分析表明,内阻尼越大,对系统的振动越具有抑制作用;材料阻尼比越大,系统越稳定;内阻尼与自身材料阻尼比都与振型有关.
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