Dynamic Behavior of Three-wheeled Vehicle Under Random Road Characteristics Using FEM
In general three wheelers are one of the most popular city transport vehicles in the world and particularly in developing countries especially for short hauls. In the present work finite element model of three wheeled motor vehicle chassis has been developed using ANSYS software by taking into account the chassis longitudinal/cross members, the suspensions, the axles and the tires. Modal analysis is carried on the three wheeled motor vehicle chassis using Block Lanczo's technique to obtain the natural frequencies and mode shapes. Vertical dynamic response of the three wheeled motor vehicle chassis has been carried in the frequency domain by performing the spectrum analysis using ANSYS software. When the vehicle moving at 45 kmph on different Indian and International roads, and the response is obtained at four significant points i.e. at node 2 (rear part of the chassis sprung mass), at node 8 (passenger seat position), at node 657 (rear axle) and at node 34 (steering position). The response i.e. power spectral density of acceleration is compared between the Indian and International roads and different modes which affect the passenger comfort are also discussed using spectrum analysis. Parametric study has also been carried out using the finite element model to study the effect of various parameters and to find the optimum values both quantitatively and qualitatively, in the ride response of the vehicle. Finally based on the above analysis certain recommendations are made about manufacturer point of view.
Dynamic Response of Tractor-Semitrailer Vehicle to Random Inputs
This paper is concerned with the dynamic analysis of vehicle-road using the theory of stochastic processes. The tractor-semitrailer vehicle is treated as a discrete, linear, time-invariant dynamic system subjected to a stationary random input from the road surface. The vehicle model, including primary and secondary suspension systems, and subject to both heave and pitch motions, has six degrees of freedom. A representation of random roughness of the road is given, frequency domain analysis is applied, and a parametric study is presented. The theoretical investigation described in this paper represents an attempt to obtain a better understanding of the significant parameters of vehicle construction and road characteristics involved in (a) the vibrations transmitted from the roadbed to the tractor-semitrailer vehicle, (b) the dynamic forces at the tyre-road interface. The results of the computer analysis of vehicle and road are presented in two forms; the amplitude spectra and the root mean square amplitudes which are used to predict vehicle ride quality and evaluate the design concepts. (Author/TRRL)
Ground Fault Protection for Electric Utility Generating Station Medium Voltage Auxiliary Power Systems
Most generating station designs have medium voltage auxiliary power systems with low resistance grounded neutrals.1 In order to provide even higher reliability, the auxiliary power distribution system configurations supply increasingly redundant process equipment.