The Shock Strength And Vibration Fatigue Studyon Railway Vehicle High Voltage Box

During the operation of railway vehicles, the car body and its suspension devicesuffer the shock and vibration from complex working conditions, which is inevitable.With the continuously growing speed of railway vehicles, the stress state of railwayvehicle electrical equipment becomes worse and worse. The machinery box of railwayvehicle electrical equipment is an important factor in the overall performance securityappliances, whose structural strength directly affects the vehicle operator safety.Therefore, it is necessary to evaluate the structure strength through the simulationanalysis method in the design process for such devices.Railway vehicle electrical equipment primarily withstand shock, vibration andother dynamic loads effects in the practical application, however, engineers usuallyadopts the traditional static analysis method to evaluate it, but it could not simulate theactual stress state of these equipments. This thesis takes a certain type of railwayvehicle high voltage box as the study object. By using dynamic analysis method basedon finite element method, the author accomplished the numerical simulation of shockand vibration test, achieving the unity of assessment methods in the design stage andprototype test stage, so that we can make sure whether the product can pass the shockand vibration tests or not in the design stage.In order to avoid the resonance of railway vehicle electrical equipment and the carbody, and to avoid the phenomenon of obvious global resonance in the vibration test,modal analysis is carried out on the high voltage box, besides, the shape and causes oflow order modal are studied.The shock strength was calculated on the high voltage box, by using the directstatic analysis method, inertia relief method and transient response analysis method.The analysis of the three calculation results were compared and analyzed, the resultsshow that: the calculated stress through these three methods are lower than thematerials allowable stress. It means that shock strength meets the requirements. Directstatic analysis method and the inertial release method are equivalent. Transientresponse analysis is consistent with the other two methods of stress trend, but the calculated stress of the transient response analysis is greater, so it is better to usetransient response analysis method to calculate the shock strength of the railwayvehicle electrical equipment.By using random vibration analysis method based on frequency domain, thevibration fatigue analysis was carried out on base material and weld of the high voltagebox main structure. The high voltage box main structural damage is less than1, thefatigue strength meets the requirements. The maximum fatigue damage value is0.51,which appears at the plug weld of the bottom of longitudinal triangular beam. Inaddition, the weak parts of fatigue strength and shock strength of the high voltage boxare almost coincided.In this paper, the finite element simulation technology is applied in the railwayvehicle electrical equipment in the design process. It can verify the rationality of thedesign scheme timely, shortens the development time effectively, and reduce the designcost.