比較Bernoulli-Euler樑與Timoshenko樑在移動外力下波的傳遞分析

Compared the Wave Propagation between Bernoulli-Euler Beam and Timoshenko Beam under a Moving Force

楊哲維(Jer-Weir Yang)

《建國科大學報》 25卷4期 (2006/07) Pp. 61-80

https://doi.org/10.6995/JCTU.200607.0061

摘要

Bernoulli-Euler樑與Timoshenko樑的差異在於後者多考慮了剪應力與轉動慣量的效應，故Timoshenko樑其結構阻抗與結構阻尼的項次將變得更複雜。而本文的主要目的則是探討在移動外力作用下，兩種樑的結構系統阻抗、阻尼與近場及遠場波傳遞行為的變化，將比較出Bernoulli-Euler樑與Timoshenko樑的結構阻抗根值與速度增加間的關係及根值所代表的物理現象，進而描述移動力對結構振動所產生的都卜勒效應影響。其次並比較樑在彈性基底時，承受移動負載的動態響應效應，亦說明了速度的增加將造成四種波的傳遞現象。

關鍵字

移動外力 ； 傳遞波 ； Bernoulli-Euler樑 ； Timoshenko樑

並列摘要

The difference between Bernoulli-Euler Beam and Timoshenko Beam is that the latter considers the effects of shear stress and momentum inertia. Therefore, the terms of structural impedance and structural damping of Timoshenko Beam become more complicated. The purpose of this paper is to explain the variation of wave propagation of the structural impedance, damping, near-field and far-field between two beams under a moving force. It will compare the relation between roots and the increase of velocity of structural impedance of Bernoulli-Euler Beam and Timoshenko Beam, as well as the physical phenomena of roots. Furthermore, it will describe structural vibration of the Doppler effects that caused by a moving force. Besides, comparison of structural dynamic responses sustained from moving load under elastic foundation is administered. It explains four wave propagation phenomena caused by increase of velocity.

並列關鍵字

Moving Force ； Wave Propagation ； Bernoulli-Euler Beam ； Timoshenko Beam