第八讲轨道力学3-enppt课件.ppt

任娟娟博士、副教授Ren,,SouthwestJiaotongUniversityRailwayTrackEngineering铁路轨道1第四章轨道力学Trackmechanics本讲主要内容概述(Instruction)轨道结构竖向静力分析(Verticalstaticanalysisoftrackstructure)轨道强度检算(Calculationofstrengthoftrack)扣件力学分析( Mechanicsanalysisoffasteners)车辆脱轨条件(Conditionsoftrainderailment)轨道不平顺(Trackirregularity)车辆曲线通过(Vehicleoncurvedtrack)轨道动力学简介(Introductionoftrackdynamics)2四、扣件力学分析Mechanicsanalysisoffasteners扣件的功能要求Functionrequirementoffasteners基本要求:联结、调整Basicrequirement:connection,adjustment力学要求:阻力(防爬)、弹性(减振)Mechanicalrequirements:ponentofelasticfastener弹性扣压件、轨下胶垫、板下胶垫Clip,railpad,railseatpad3四、扣件力学分析(rigidityoffastener):扣压件刚度(rigidityofbar-springclip),轨下胶垫刚度(rigidityofrubberpadunderrail)并联关系(Parallelrelationship)Kc/2KpKhKhKc/24四、扣件力学分析*(initialtoeloadoffastening)作用(function):防爬(anti-creep)(R扣>R道) 稳定钢轨每组扣件纵向阻力:(longitudinalresistanceofeachgroupoffasteners)单位长度纵向阻力:(longitudinalresistanceofperunitlength)小阻力扣件(Smallresistancefasteners)(R扣<R道)f1钢轨与扣压件摩擦系数f2钢轨与胶垫摩擦系数Pc两扣压件扣压力a枕间距5四、扣件力学分析(stiffnessmatching)*初始扣压力:弹条初始变形≠胶垫初始变形(initialtoeloadoffastening)枕上动压力:弹条变形=胶垫变形(sleeperdynamicpressure)为保证钢轨的稳定,需防止弹条松动 Rd下压力防止胶垫松弛 Rd上拔力6四、扣件力学分析(lossoftoeloadoffastening) 扣压力损失(lossoftoeloadoffastening) 损失后的扣压力(toeloadoffasteningaftertheloss) 应能保持防爬、防翻等作用(Withgoodanti-creepandanti-turnroundfunction)7五、车辆脱轨条件(Conditionsoftrainderailment)(typeofwheelderailment)车轮爬轨脱轨(railcreepderailment):横向力、正冲角车轮滑上脱轨(wheelsliponderailment):横向力、负冲角车轮跳轨脱轨(wheeljumpingderailment):横向冲击、高速车轮悬浮脱轨(wheelsuspensionderailment):轮重减载至0车轮掉道脱轨(wheeloffthetrackderailment):轨距过大轨道破坏脱轨(raildamagederailment):positederailment):多种原因引起8五、车辆脱轨条件(Conditionsoftrainderailment)(causesofderailment)(1)轨道状态(trackcondition)外轨超高设置不当,导致轮重增减载(wheelloadincreaseorreduction)超高顺坡、三角坑、不均匀支承等使车体产生扭曲,引起轮重增减载和加剧横向摇摆(lateralswaying)轨道横向不平顺、小半径曲线、