A Study on the Nonlinear Vibration of Bolted Joints in CNC Machine Tools

Bolted joints are widely used in CNC machine tools and the presence of joint interface results in discontinuities in the local stiffness and damping of the structure, which affects the dynamic characteristics of CNC machine tools. This paper focuses on identification techniques for the nonlinear characteristics of bolted joints from experimental perspectives: (1) Time-domain methods and frequency-domain methods are applied for detecting nonlinear vibration problems on a test specimen which resembles the actual situation in CNC machine tools, (2) Application of the restoring force surface method is considered for parameter estimation of the same test specimen. Through experimental tests and discussion, it's shown that the test specimen has the stiffness softening characteristic and the methods used in the experiments are effective for the study of nonlinear vibration problems.