Mechanisms of high-frequency force generation in hydraulic automotive dampers.

The paper describes progress of research into the mechanisms of high-frequency (up to 500 Hz) force generation in hydraulic automotive dampers. A test facility for making measurements of high-frequency behaviour is described. The force response of a monotube damper to double-sinusoid displacement inputs is presented. Wavelet analysis is used to aid identification of the force generation mechanisms. Friction is found to make a significant contribution, particularly at changes in sign of damper velocity and at high frequencies. An existing mathematical model of a damper is modified to improve the representation of friction, and it is found that prediction of force response to a random displacement input is significantly improved at frequencies above 50 Hz. [ABSTRACT FROM AUTHOR]