Analysis Of Train Safety On Bridge Under Pseudo Excitation

With the continual developing of high speed railway, the constant augment ofrunning speed and the gradual increase of the loads, the vehicle-bridge dynamicinteraction becomes a crucial factor day by day which involves in vehicle safetyoperation and bridge normal use. The vehicle-bridge coupling vibration is a dynamicissue which has the characters of random, self-excited and variation as the time,which makes the analysis of this question have prodigious complexity and difficulty.And the issue of vehicle-bridge coupling vibration has been a difficult point and hotissue which scholars and professionals in many countries devoted to.In this thesis, the history and the state-of-the-art reviews of researches onvehicle-bridge coupling vibration are introduced, and numerous scholars’ researchresults are summarized. According to Lagrange Equation, the motion equation offour-axis vehicle with23degrees of freedom is deduced. And the wheel-rail contactrelationship is analyzed and calculated. The wheel-rail relationship is regarded as theconnection of vehicle-bridge coupling system, in the analysis of vehicle dynamicresponse, the wheel-rail force and lateral static wind loads are regarded as externalexcitation, and then the study about Gou-he bridge in Qin-shen passenger railway lineand a train with eight carriage is analyzed. Finally the calculation program is writtenwith Matlab software, and then the vehicle dynamic response is analyzed by usingNewmark-β step-by-step integration method. Then the influences of different windspeed and different vehicle speed to vehicle dynamic response are considered, and thefive indexs of vehicle dynamic response which include derailment coefficient, loaddecrement rate of wheel weight, wheel-rail lateral force, vehicle accelerated speed andSperling index are obtained. At last, the train operation safety on bridge is analyzed,and some conclusions are indicated: with the increase of wind speed or vehicle speed,the vehicle dynamic responses have a certain increasing trend, especially vehicleaccelerated speed and load decrement rate of wheel weight; they even overstep thesafety standards, which go against the safe operation of vehicle.