Radial gap will occur at the spindle–tool holder interface when the spindle rotates at high speed. Therefore, the radial gap will lead to the nonlinear stiffness at the spindle–tool holder connection, and it will have effects on dynamic characteristic of spindle system. In this research, classic elastic theory is adopted to evaluate the nonlinear stiffness at spindle–tool holder interface. Dynamic model of spindle system is established considering the nonlinear stiffness at spindle–tool holder interface. The fourth-order Runge–Kutta method is applied to solve dynamic response of the spindle system. On that basis, effects of drawbar force on dynamic characteristic of the system are investigated. Considering the cutting force, effects of rotational speed on dynamic response of cutter tip are also discussed. The numerical results show that the drawbar force has effects on vibration mode of cutter tip. Chaotic motion will not occur within the range concerned in engineering practice. Considering the cutting force, the motion of cutter tip turns to be chaotic. The proper rotational speed and drawbar force should be chosen to ensure a stable cutting according to the response of cutter tip.

当主轴高速旋转时，在主轴-刀架接口处会出现径向间隙。因此，径向间隙将导致主轴-刀架连接处的非线性刚度，并将影响主轴系统的动态特性。在这项研究中，采用经典弹性理论来评估主轴-刀架界面的非线性刚度。建立主轴系统动力学模型时要考虑主轴-刀架界面的非线性刚度。应用四阶Runge–Kutta方法求解主轴系统的动态响应。在此基础上，研究了牵引力对系统动态特性的影响。考虑切削力，还讨论了转速对刀尖动力响应的影响。数值结果表明，牵引力对刀尖的振动模式有影响。在工程实践中，在相关范围内不会发生混沌运动。考虑到切削力，刀尖的运动变得混乱。应选择适当的转速和牵引力，以确保根据刀头的响应进行稳定的切割。