摘要
考虑橡胶类黏弹性材料的频变特性,基于动态热机械分析仪(DMA)实测复模量得到橡胶减振垫动刚度。在此基础上,采用Comsol Multiphysics软件建立减振型CRTSⅢ型板式无砟轨道有限元模型,对比分析橡胶减振垫采用常量和频变工况下无砟轨道结构自振特性,并采用Winkler弹性地基上四边自由板的振动理论与有限元结果进行验证。结果表明:橡胶减振垫复模量随荷载频率变化而显著变化,其动刚度整体上与储存模量的变化趋势接近;橡胶减振垫频变对轨道结构整体振动和弹性模态固有频率影响是不同的,整体振动固有频率与橡胶减振垫动刚度平方根成正比,而轨道结构的弹性模态受橡胶减振垫频变特性影响较小;橡胶减振垫频变特性下,只有当外部激振频率fi与该激振频率下橡胶减振垫动刚度ki和损耗因子δi的轨道板-橡胶减振垫系统某阶固有频率相同时,该阶固有频率才为轨道板-橡胶减振垫系统的敏感共振频率。频变工况下轨道结构并非每阶都有敏感共振频率和振型,在计算参数和容差范围内,第3阶横向整体转动和第11阶弯曲模态则没有敏感共振频率和振型。
The dynamic stiffness of the rubber damping pads was calculated based on the DMA measured complex modulus considering frequency dependence of the viscoelastic rubber material.A finite element model of vibration damping CRTSⅢslab ballastless track structure was established using Comsol Multiphysics software to evaluate the natural vibration characteristics of the structure under the condition of frequency-dependent and constant parameters.The results of finite element method were compared with the vibration theory of completely free rectangular plate on winkler elastic foundation.The study shows that the complex modulus of the rubber damping pads changes significantly with the change of the load frequency,and the dynamic stiffness curve of the rubber damping pads is in good agreement with the storage modulus on the whole.The frequency variation of rubber damping pads has different effects on the overall vibration of the track structure and the natural frequency of the flexible modes,with the overall natural vibration frequency being proportional to the square roots of the stiffness of the rubber damping pads,while the frequency-dependent parameters of the rubber damping pads have less influence on the resonance frequency of the flexible modes.Under the frequency variation characteristics of the rubber damping pads,only when the external excitation frequency fi is consistent with a certain order natural frequency of the slab-rubber damping pad system with the rubber damping pads stiffness ki and loss factorδi,this natural frequency is just the sensitive resonance frequency of the slab-rubber damping pad system.Under frequency-dependent conditions,not all modal orders have sensitive resonance frequency or mode shape.The third-order lateral rigid body rotation and the eleventh-order bending mode have no sensitive resonance frequency or mode shape under the adopted parameters and tolerance.
作者
孙旭
赵才友
王平
SUN Xu;ZHAO Caiyou;WANG Ping(Key Laboratory of High-Speed Railway Engineering,Ministry of Education,Chengdu 610031,China;School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China)
出处
《铁道学报》
EI
CAS
CSCD
北大核心
2021年第7期121-127,共7页
Journal of the China Railway Society
基金
国家重点研发计划(2016YFE0205200)
国家杰出青年科学基金(51425804)
青年科学基金(51508479)。
