基于模态分析的扣件弹条扣压力测试方法

为了提出一种方便高效的扣件弹条服役状态下扣压力的测试方法,首先建立扣件系统精细化的三维实体有限元模型,分析得到扣件弹条扣压力与其固有频率的对应关系,进而提出通过测试弹条工作振动模态从而推测出弹条扣压力的间接测试方法。研究结果表明:扣件弹条扣压力与弹程基本呈线性关系,其对应关系不随轨下胶垫刚度变化而改变,就Ⅲ型弹条而言,其扣压力同弹程之比约为1. 0 kN/mm;服役状态下弹条第1阶固有频率随扣压力变化近似呈线性变化,根据Ⅲ型弹条正常服役状态设计要求以及考虑最大残余变形的安全扣压力,可得在有效扣压力范围内弹条对应的第1阶固有频率为800~1 040 Hz;通过测试服役状态下扣件弹条工作模态频率,即可间接得到服役状态下扣件弹条的实际扣压力,为辨别扣件是否失效提供科学依据和有效便捷的测试方法。

Toe Load Testing Method for Fastener Elastic Rod Based on Modal Analysis

In order to propose a convenient and eff icient testing method for the toe load of the fastener elastic rod in service,a three-dimensional solid f inite element model of the fastener system was established,and the corresponding relationship between the toe load of the fastener elastic rod and its natural frequency was analyzed.Then the indirect testing method for the toe load was estimated by testing the working vibration mode of the fastener elastic rod.The results show that the toe load and the def lection of the fastener elastic rod are basically linear,and the corresponding relationship does not change with the change of stiffness of the rubber pad under the rail.For the Ⅲ-type elastic rod,the ratio of toe load to def lection is about 1.0 kN/mm.The f irst-order natural frequency of the elastic rod in service varies linearly with the toe load.According to the design requirements of the Ⅲ-type elastic rod in normal service state and the toe load considering the maximum residual deformation,the corresponding f irst-order natural frequency of the elastic rod in the effective toe load range is 800~ 1 040 Hz .By testing the working mode frequency of the fastener elastic rod in service,the actual toe load of the elastic rod in service can be obtained indirectly,which provides a scientif ic theoretical basis and an effective testing method for identifying whether the fastener system is invalid or not.