彈性支承上的移動諧和荷重之動力分析

Abstract

本文將以高速鐵路系統來作為分析模式：亦即車廂以及鋼軌，首先旨在研究高速鐵路 之軌道系統，在一高速移動的諧和荷重作用下鋼軌的動力反應。 隨著荷重移動速度改 變，震動頻率之改變而去探討鋼軌動力反應函數的情形。而後可求得其軌道阻抗勁度係數 。研究中乃假設鋼軌為無限長梁置一黏彈性支承上，經由運動方程式之推導及傅立葉轉換 求其變位和阻抗係數。並應用了FFT來對照其正確性。而後乃在獲得了阻抗勁度係數後， 即將上部車廂與鋼軌間模擬成雙自由度之結構動力系統，應用結構土壤互制的理論推導此 時之運動方程式。即可探討當車輪與鋼軌間有一突跳變位時對上部車廂的震動分析。 文中將對世界三種高鐵系統進行分析，即法國T.G.V.和德國I.C.E.及日本S.K.S.。同時更 探討了於更高速度與較高震動頻率下的移動荷重對於鋼軌的動力反應狀況，本論文中有進 一步之研究。 This paper will set up the analytical model for system ofhigh-speed rail ro ad.The model will include vehicle and steeltrack and elastic foundation.The dy namic response of steeltrack under a high-speed harmonic moving load of rail-s ystemis studied first. By the change of load-velocity and vibratorycircular fr equency, we can explore the behavior of dynamicresponse due to harmonic excita tion. Therefore, the impedanceof the rail can be found. Then, the vehicle resp onse due toarbitrary excitation can be obtained using Fourier Transformati I n this paper, we assumed steel track as an infinite beamthat based on viscoela stic foundation. By the derivation ofequation of motion, we can find the defle ction and impedance.For same cases, this can be check by FFT. After getting the impedance, we can combine the vehicle andsteel track into structural dynam ic system of 2-DOF. Applyingthe theorem of soil-interaction to this system, eq uations ofmotion are derived. Then, we can study the vibration of thevehicle a nd response of the steel track due to toughness ofsteel track. Finally, thre e systems are taken for examples in order toillustrate the fitness and usefuln ess of the method presentedby this paper: T.G.V. France, I.C.E. Germany, S.K.S . Japan.At the same time, the responses of higher speed and circularfrequency are studied. There are some discussions in the paper too.