Experimental Study on Fatigue Damage Characteristics of Equipment Compartment Bottom Plates of EMU

doi:10.3901/JME.260052

Abstract

Abstract: The fatigue strength of the vehicle equipment compartment floor is affected by vibration and aerodynamic loads and other factors, so it is more prone to fatigue damage, and its fatigue strength is a safe use of the vehicle can not be ignored. Taking a certain type of railway car body equipment compartment floor plate as the research object, we completed the dynamic stress measurement point arrangement of the equipment compartment floor plate and its mounting beams, and conducted the tracking test on a dedicated passenger line. Based on the test dynamic stress data, the stress spectrum of each fatigue key point is obtained by digital signal processing and statistical counting. Combined with Miner's damage theory and the S-N characteristics of the base material and welds, we calculate the unit mileage damage and equivalent force amplitude of each measurement point of the equipment compartment floor and its mounting beams under the whole life cycle, analyse the effects of changes in operating conditions such as speed level, open line steady state and tunnel passage on the stress response characteristics and fatigue damage, and analyse the frequency domain characteristics of the dynamic stresses in the equipment compartment floor and the contribution of the vibration energy of the uneven frequency band to the fatigue damage of it. Contribution of vibration energy to fatigue damage.The results show that: Compared with the straight line operation, the curve through process does not have a significant effect on the stress on the bolt mounting holes of the equipment compartment floor plate, the increase of the equivalent stress amplitude is less than 3 MPa.The application of the equipment compartment floor plate in the windward side of the damage to a certain extent than in the case of the non-windward side of the equipment compartment floor plate. The fatigue damage at the centre of the equipment compartment floor plate is due more to longitudinal vibration, and both longitudinal and lateral vibration contribute to some extent to the fatigue damage at the edge of the mounting holes, with the contribution of the 20-40 Hz component being dominant. As the speed of travel increases, the elastic vibration of the equipment compartment floor plate is more likely to be stimulated. When passing through the tunnel, there is a significant increase in the vibration amplitude at the principal frequency of 22 Hz, and there is little change in the corresponding amplitude and frequency characteristics of the other principal frequencies.

Key words: EMU, equipment compartment floor, dynamic stress, fatigue, operating conditions, frequency domain characteristics

CLC Number:

U270

XU Ning, SUN Zhanyong, YANG Chao, REN Zunsong, YANG Guangxue, ZHOU Yichang, QU Sheng. Experimental Study on Fatigue Damage Characteristics of Equipment Compartment Bottom Plates of EMU[J]. Journal of Mechanical Engineering, 2026, 62(2): 250-260.

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