EP70 Nigerian Boxcar Body Performance And Dynamic Characteristics Analysis

With the continuous development of China’s economy and the deepening of industrialization,railways,as an efficient and reliable modern transportation method,have been widely used in the field of freight transportation.Against the background of China’s increasing international influence and infrastructure level,China has long been committed to strengthening unity and cooperation with African countries and regards it as a strategic choice.Nigeria,as one of the important countries cooperating with China in the railway industry,has relatively harsh railway routes and natural conditions,and has more stringent requirements for vehicle performance in order to meet the demand for railway vehicles exported to the region.This article focuses on the EP70 type export Nigerian boxcar as the research object.Based on the finite element theory,the stiffness,static strength,modal,stability,and fatigue of the vehicle body were analyzed.On this basis,a fine analysis method for the vehicle’s random vibration characteristics was carried out using the virtual excitation method as the core of the random vibration analysis.The main research contents are as follows:(1)The structure and characteristics of the vehicle body are described,and a finite element model of the vehicle body is established;the static strength and stiffness working conditions of the vehicle body are determined according to the AAR standard,and the calculation and analysis are carried out.The results show that the stiffness and static strength of the vehicle body under all working conditions meet the design requirements.(2)A modal analysis was performed on the steel structure and 70-ton loading state of the vehicle body.Subsequently,a buckling analysis of the vehicle body under compressive working conditions was conducted in accordance with the TB/T3550.2-2019 standard,which yielded the vehicle’s critical unstable load,buckling factor,and unstable position.The results indicated that the roof of the vehicle body is comparatively prone to resonance as compared to other locations,and the buckling stability coefficient was found to satisfy the requisite standard specifications.(3)By utilizing the nominal stress method,the fatigue strength of the vehicle body was analyzed by combining the AAR and BS standards.Based on the calculation results,the WeldFatigue software,which is based on the structural stress method,was used to evaluate the fatigue life of four welds.A comparative analysis of the two fatigue assessment methods was carried out,and the results indicated that the fatigue life of the vehicle body meets the design requirements.(4)A refined analysis method of random vibration,which uses virtual incentives as its core,was adopted to establish a vehicle dynamics model based on the finite element model of the car body.From both the overall and key parts perspectives,the random vibration characteristics of the car body were analyzed.The results showed that the frequency of the vibration energy increase of the car body under various working conditions was consistent with the modal excitation frequency.(5)According to the GB/T5599 standard,a refined analysis method of random vibration,which uses virtual incentives as its core,was adopted to evaluate the lateral and vertical stability of the car body under different speeds in empty and loaded conditions.The results showed that,except for the lateral stability of the car body under the empty condition at speeds of 120km/h and 100km/h,which was rated as good,the stability rating of the car body under all other speeds was excellent,indicating good dynamic performance of the vehicle.