Papers by Keyword: Mode Coupling

Abstract: The improved equations of motion for a friction-engaged brake system have been newly derived on the basis of the assumed mode method and frictional damping. The equations of motion with a finite element model were constructed by a set of vibration modes found from FE modal analysis on all system components. Consequently, the modal information of system components are combined with equations of motion derived from the analytical model. Numerical analysis showed the mode which was unstable in an undamped case became stable in a damped case.

Abstract: A finite element model of a water lubricated rubber bearings system is established by using ABAQUS software. A complex eigenvalue analysis of the bearings system is performed. The occurrence propensity of noise is evaluated on the basis of positive and negative of the real parts of eigenvalues. If there are one or more positive real parts, the system is considered to have the propensity of noise occurrence. In the ABAQUS approach, the direct contact coupling at the shaft/bearing interface is applied to obtaining normal contact forces and there is no need to introduce contact springs at the interface. The approach is easily used to establish a non-flat sliding contact model for noise. By using the ABAQUS finite element model, effects of the friction coefficient, the properties of rubber material and the thickness of rubber are studied. The results show that the friction coefficient, the properties of rubber material and the thickness of rubber have distinct effects on the occurrence of noise.

Abstract: Wedge waves (WW) are guided acoustic waves propagating along the tip of a wedge, with energy tightly confined near the apex. Like Lamb waves, wedge waves with displacement field anti-symmetric about the mid-apex-plane are called anti-symmetric flexural (ASF) modes. This study is focused on exploring the dispersion behaviors of ASF modes propagating along a bilinear wedge (BW). A BW is wedge with a cross section of two apex angles, compared with a linear wedge (LW) having a single apex angle. In the literature, many studies regarding to the dispersion behaviors of ASF modes are reported for LW, but not for BW. In this study, a laser ultrasonic technique and finite element simulations are used to investigate the dispersion behavior of BW-ASF modes. It is found out that a BW-ASF mode is a result of mode coupling between the two LW-ASF modes of the same order corresponding to the two apex angles of the BW.