【作者】 闫光杰； 阎贵平； 方有亮；

【Author】 YA Guang-jie, YAN Gui-ping, FANG You-liang(School of Civil Engineering & Architecture, North Jiaotong University, Beijing 100044)

【机构】 北方交通大学土木建筑工程学院；

【摘要】 对比研究了匀速移动质量或等效移动集中力(忽略移动质量的惯性作用,只考虑其重力)作用下简支梁的动力响应及相应的临界移动速度。研究结果表明:1)等效移动集中力作用下,简支梁的动力响应由稳态响应和瞬态响应组成。在过去的研究中,临界移动速度是仅考虑稳态响应得到的。若同时考虑两部分响应,则临界移动速度约减小38%。因此,不能忽略瞬态响应对临界移动速度的影响。2)由于移动质量的惯性作用,随着移动质量与简支梁的质量比的增大,移动质量情况的临界移动速度比等效移动集中力情况大大缩小。3)当质量比小于1%时,临界移动速度缩小不到5%,此时可以近似忽略移动质量的惯性作用,简化为等效移动集中力情况。以上结论对于提速列车对桥梁结构的影响研究具有重要的实际意义。更多还原

【Abstract】 Dynamic responses of a simply supported beam under a moving mass and critical moving velocity were analyzed and compared with the corresponding behavior of that subjected to an equivalent moving concentrated force neglecting the inertial effects of the mass. The results are shown that: 1) under an equivalent moving concentrated force, dynamic responses of the simply supported beam consist of steady response and transient response. In the past research, the critical moving velocity with which the maximum dynamic deflection reaches maximum was obtained only considering steady response. Taken into account two responses, the critical moving velocity is shortened by approximately 40%. Thus, the effect of transient response on critical moving velocity cannot be neglected. 2) Because of the inertial effects of the mass, with the increase of mass ratio between the moving mass and the simply supported beam, the critical moving velocity is smaller than under an equivalent moving force. 3) For the beam given in this paper, the inertial effects of the moving mass can be neglected if mass ratio is less than one percent, and the response of simply supported beam under moving mass can be simplified as that under an equivalent moving concentrated force. These conclusions have some significance for the research of the effect of the vehicles with increased velocity on railway bridge structures.更多还原