钢轨扣件减振橡胶阻尼耗能特性分析

为了掌握钢轨扣件减振橡胶中阻尼的分布及其随振幅和频率的变化规律,对减振橡胶元件受压和受剪两种扣件进行了试验研究。建立钢轨扣件减振橡胶非线性弹性力和混合阻尼叠加的动力学模型,完成模型参数识别及结果检验。根据所建立的动力学模型计算各试验工况下的弹性变形能、阻尼耗能和结构损耗因子。分析发现:压缩和剪切两种扣件减振橡胶的阻尼参数随振幅和频率的变化规律相似,弹性变形能、阻尼耗能和结构损耗因子均随振幅的增大而显著增大,而受频率的影响较小。相同工况下,压缩型扣件减振橡胶的结构损耗因子远大于剪切型扣件,说明压缩型扣件在发挥减振功能时,其耗能特性优于剪切型扣件,而隔振特性劣于剪切型扣件。因此,在钢轨扣件创新设计时,可以通过控制减振橡胶压-剪组合变形,来实现扣件隔振和衰减振动能量两功能的均衡发挥,将结构损耗因子作为设计过程中的控制指标。

Analysis of Structural Damping Property of Rail Fastening Rubber Absorber

To understand the rules of damping distribution and changes in amplitude and frequency of rubber absorber of rail fastening,two kinds of rail fastenings with compressed and sheared rubber absorbers respectively are tested. A nonlinear dynamic model of rubber absorber coupled with nonlinear elastic force and mixed damping in rail fastening is established with model parameters identified and results verified. Elastic deformation energy,damping dissipation energy and structural loss factors are calculated based on the proposed model. The results show that calculated damping parameters of the two rubber absorbers follow the similar rules,the elastic deformation energy,damping dissipation energy and structural loss factor increase rapidly with the increasing of amplitude,and are affected less by frequency.Structural loss factor of the compressed rubber absorber is much bigger than that of sheared rubber absorber under the same experimental condition,which indicates that the compressed rubber absorber has a better damping capacity than that of the sheared rubber absorber,but the sheared rubber absorber has a better capacity of vibration isolation. As a result,vibration isolation and energy dissipation can be balanced through combined deformation of compressed and sheared rubber absorbers to design new rail fastenings,and structural loss factor taken as a control index.