| In the era of"transportation power,railway first",increasing speed,axle load and marshalling is a main direction of heavy haul railway in the future,and this will lead to the increase of the dynamic interaction between the train and the heavy haul railway bridge,which is more prone to the phenomenon of the dynamic response over the limit.This also means that the security of heavy haul railway faces more challenges.Therefore,it is necessary to evaluate the adaptability of existing bridges to the operation of heavy axle load trains.The rigid-flexible coupling method,which has the advantages of high computational accuracy and high efficiency,is used to build the co-simulation model of the vehicle-bridge system,and it is an advanced research method in this field.At the same time,in the actual operation of the circuit,the dynamic response of the whole system is affected by the random superposition of external load and its own structural parameters.Based on this,this paper establishes a refinement dynamic model of heavy-haul railway vehicle-bridge coupling,studies the random vibration of the vehicle-bridge coupling system,and analyzes the random characteristics and sensitivity of structural parameters from the perspective of statistics and probability.The influence of different parameters on the dynamic response of the system is analyzed,and relevant measures and suggestions are put forward to provide theoretical basis for the actual operation and future development of heavy haul railway.The main research work of this paper is as follows:(1)The dynamic test of a heavy haul railway bridge is carried out,including the vibration and deformation of the bridge structure,and the time-domain analysis and probability statistical analysis of the dynamic response of the bridge under different axle loads and velocities are carried out.The preliminary conclusions about the sensitivity and random characteristics of the structural parameters are obtained.Based on the principle of triple standard deviation,the maximum estimate of the dynamic response of the bridge is deduced,and its influence on the safety of the bridge is analyzed.(2)A refinement rigid-flexible coupling simulation model of heavy haul railway vehicle and bridge is established,including rail,sleeper,track bed,bridge superstructure,bridge pier structure and vehicle.The degree of freedom,motion equation and wheel-rail contact relationship of the multi-rigid model of vehicle are introduced in detail.The process of substructure reduction and modal analysis of the flexible body model of track-bridge structure is described,and the basic principle,steps and matters for attention of rigid-flexible coupling simulation are explained.After the model is established,the correctness is verified by comparing with the test data,and the evaluation index of the dynamic performance of the vehicle-bridge system is selected.(3)The vehicle-bridge coupling simulation model is used to calculate the influence of single factor change of train speed or axle load on the dynamic response of the system under the condition that the track bed thickness is normal,and the influence on the dynamic response of the system under the interaction of the track bed thickness and train speed or axle load is analyzed.Correlative measures and suggestions are put forward,which can be used to guide the actual operation and maintenance of the line.(4)Combining SIMPACK DOE and Design-Expert software,based on the related theory of experimental design,2~k factorial experiment is selected to analyze the parameter sensitivity that has an effect on the dynamic response of the bridge.The Box-Behnken method used in response surface experiments is used to derive the correlation function between the sensitive factors and the dynamic response of the bridge,and the combination of the factors level when the response obtained the optimal value was analyzed through the optimization design.There are 69 figures,36 tables and 93 references. |
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