【作者】 镇斌；

【导师】 谢伟平；

【作者基本信息】 武汉理工大学 ， 结构工程， 2005， 硕士

【摘要】 一个多世纪以来铁路运输已发展成为世界主要公共交通形式之一。近十年来,世界各国,如欧洲,日本,中国,更是已兴建或正在兴建数量众多的地铁和高速铁路。研究铁路轨道在高速列车作用下的振动对于交通工程有很重要的现实意义,分析列车运动荷载引起的波在轨道中的传播对于防止轨道的破坏,保证列车的安全运行也很有必要。对铁路钢轨,一般采用Bernoulli-Euler梁和Timoshenko梁来建模,为了简化问题,首先只考虑单个移动荷载的作用。本文主要分析了无限长梁在移动荷载作用下的稳态动力响应和临界速度。具体工作如下: 1.通过对无限长Bernoulli-Euler梁系统动力响应的分析,运用留数定理得到了无自振匀速移动荷载下无限长梁的稳态动力响应的解析表达式。 2.详细比较分析了无阻尼和有阻尼情况下无限长Bernoulli-Euler梁系统动力响应的区别。所得到的结论可直接应用于Timoshenko梁。 3.探讨了自由振动时无限长Bernoulli-Euler梁和Timoshenko梁中波的性质。 4.探讨了无限长Bernoulli-Euler梁和Timoshenko梁的临界速度和共振频率之间的关系。并对得到的临界速度和共振频率给出了相应的物理解释。更多还原

【Abstract】 Railway train has been a major form of public transportation in the world for more than one and a half centuries. In the last decade, many subways and high-speed railways, including those in Europe, Japan, China, have been constructed or are in construction stage. It’s significant to study the response of rails caused by high-speed trains, and the propagation of waves in the rails, for the protection of rails and the security of trains. Beraoulli-Euler and Timoshenko beam models have been used to study the response of the rail under moving loads since the last century, in which only one single moving load has be considered, which is simpler and has no influence to the problem itself. In this paper the steady-state responses and critical velocities of the infinite beams under a moving load will be discussed. All has been done as following:1. Fourier transform is used to solve the problems of steady state response of an infinite beam on a viscous foundation subjected to a moving load. The theorem of residue is employed to evaluate the generalized integral so that an analytic solution can be achieved for the case of constant velocity, to both Bernoulli-Euler beam and Timoshenko beam.2. The influence of damping to the dynamic response of the beam is discussed clearly, which is a key point for solving this problem. The conclusion drawn from the analysis to Bernoulli-Euler beam model can be applied to the solution of Timoshenko beam model directly.3. The characteristics of waves propagated in the Bernoulli-Euler and Timoshenko beam that vibrate freely have been analyzed, as the basis of the solution to the critical velocities.4. The relationship between the critical velocities and resonant frequencies has been obtained, as well the explanations in physics of which.更多还原