On the Design of a Yaw Colloidal Damper Used to Suppress the Hunting Motion and to Improve the Travelling Stability of a Bullet Train
The yaw damper is a primary source of excitation for the railway carbody’s flexural vibration. To decrease the transmission of such unwanted excitation, the yaw damper should allow for substantial force transmission at low working frequencies while acting as a vibration isolator at higher working frequencies. Unfortunately, the yaw oil damper, which is now in use, has limited inherent elastic capacities and produces damping forces that change as a power function of piston speed. Colloidal dampers are an intriguing alternative to standard yaw dampers because they have intrinsic elastic properties and greater damping forces at lower excitation frequencies. The working conditions to be met by the yaw damper are detailed in this chapter, which begins with a simple but reliable analytical formula to estimate the negative damping happening spontaneously during the hunting motion of the railway wheelset. In particular, technical methods for reducing the consequences of the wheelset unstable hunting mode are mentioned, as well as the impact of carriage geometry, hunting wavelength, and lateral disturbance on the yaw damper stroke. The ride comfort of a bullet train subjected to lateral stimulation is compared to the normal approach in order to determine the effectiveness of the yaw damper. as well as by taking into consideration some specific frequency weightings that account for the discomfort experienced by passengers when reading and writing. The dynamic parameters of a yaw colloidal damper, which will be used to suspend the carbody of a full-scale bullet train, are then analysed using experimental data acquired during horizontal vibration tests on a ball-screw shaker. The frictional and colloidal effects of the yaw colloidal damper are studied in relation to the working stroke and frequency. The experimental yaw colloidal damper allows for a 31.6 percent weight decrease when compared to the similar classical yaw oil damper. Long piston stroke with low excitation frequency produces big damping force, dissipated energy, and spring constant; short piston stroke with high excitation frequency produces low damping force, dissipated energy, and spring constant. The yaw colloidal damper’s elastic properties are explained using a model that includes the effect of a porous lyophobic matrix on the behaviour of a classical liquid spring.
Author (S) Details
Department of Intelligent Mechanical Engineering, Faculty of Engineering, Fukuoka Institute of Technology, 3-30-1 Wajiro-Higashi, Higashi-ku, Fukuoka-shi, Fukuoka 811-0295 Japan.
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