The air spring is a pneumatic device that is sensitive to changes in environmental parameters. Therefore, it is necessary to establish a pneumatic hydrodynamic model of the air spring based on the AMESim simulation platform. In this model, the thermodynamic process of the gas inside the air spring and the relationship between the effective area and the internal pressure are considered. Since the stiffness of the emergency rubber spring is much larger than the stiffness of the rubber bladder, emergency rubber is not considered in the normal working state of the air spring. The stiffness of the spring. In addition, the vehicle multi-body dynamics model is established based on SIMPACK, and combined with the air spring aerodynamics model in AMESim, the reaction force of the air spring is used as the input of vehicle dynamics calculation, and the vertical displacement of the vehicle body. As an output, the joint simulation diagram is shown. In the dynamic analysis of the train intersection, taking the time history of the vehicle flow field pressure Pv as input, the two trains are calculated by co-simulation to achieve the same speed on the straight line at speeds of 250km/h, 50km/h and 50km/h. The aerodynamic response of the air spring during the rendezvous and the dynamic response of the EMU.
The multi-body dynamics model of the vehicle and the aerodynamic fluid dynamics model of the air spring are combined. The dynamic stiffness of the air spring has a great relationship with the internal pressure. Before studying the dynamic performance of the EMU, it is necessary to study the air spring at the time of the train rendezvous. Pneumatic response. The change of the external air pressure of the air spring adopts the vertical stability of the horizontal stability 2502.1332.7563502.2003.1074502.2653. According to the specification requirements, for the certain type of EMU selected in the example, the limit of the vertical force of the wheel and rail is 170kN; The limit of force is 56.26kN; the limit of derailment coefficient is 0.8; the limit of wheel load shedding rate is 0.8. Numerical simulation is carried out under different vehicle speed conditions to obtain the dynamic response of the vehicle, and each work is selected. In the case of the worst dynamics of the wheelset response curve, the safety limits are plotted.
(C) Derailment coefficient (d) Wheel weight reduction rate Vehicle dynamic response during vehicle process According to the response curve of the vehicle during the vehicle, it can be seen that in several safety indicators, the wheel and rail vertical force and wheel weight reduction The load factor has a large safety margin during the vehicle's journey; while the axle lateral force and derailment factor exceed the safety limit in a short period of time at 450 km/h.
This is because the lateral force of the pneumatic flow field of the vehicle on the vehicle body is large, which mainly affects the safety index related to the lateral force of the wheel and rail. By observing the peak point of the axle lateral force and the derailment coefficient exceeding the safety limit, it is known that the dangerous point of the operational safety index generally appears at the moment when the nose of the front of the rendezvous train passes the observation point, so it should be managed in the design of the nose of the high-speed train. Reduce the initial pressure wave amplitude when the vehicle is in use to improve the operational safety of the EMU during high-speed meeting.
4 Conclusion Based on the research results of train aerodynamics, the air pressure change of the train intersection flow field is used as the external excitation, and the multi-body dynamics model of the vehicle is combined with the aerodynamic fluid dynamics model of the air spring to calculate the two trains. The group responded with the aerodynamic response of the air spring at different speeds and the dynamic response of the vehicle, and obtained the following main conclusions: When the EMU and the oppositely-traveling train meet, the air spring caused by the change of the pressure wave of the vehicle The pressure fluctuation is much smaller than the pressure fluctuation caused by the roll of the car body. Therefore, the internal pressure change of the air spring is mainly affected by the roll of the car body. The change trend of the internal pressure of the bogie near the air side of the car side and the change trend of the aerodynamic flow field of the car On the contrary, the internal pressure of the air spring on the other side of the bogie has the same tendency.
The higher the speed of the EMU rendezvous, the greater the change of the internal pressure of the air spring. When the rendezvous speed is 450km/h, the maximum fluctuation of the internal pressure of the air spring can reach 30.78%. The lateral vibration of the vehicle body is more than the vertical vibration. The impact of the field is greater, and the vertical stability of the vehicle is better than the lateral stability at all speeds.
The wheel-rail vertical force and wheel load shedding rate are less affected by the pneumatic flow field of the car. These two safety indicators still have a large safety margin during the vehicle, but the axle lateral force and derailment coefficient are The 450km/h condition will exceed the safety limit in a short period of time, and the maximum of these two safety indicators will appear at the moment when the nose of the nose passes through the observation point.
Aluminum Alloy 3000 Series Bar
1.Mechanical Properties of Aluminum Alloy 3000
Tensile strength (25 C MPa): 175-470
Hardness 500kg force 10mm ball:60-120
Yield strength (25 C MPa): 195-325
Extensibility 1.6mm (1/16in) thickness: 12-20
2.Dimension: Customized dimension, OEM & ODM
3.Material: A3003,A3004 and other series alu alloy
4.Suface treatment: Anodizing, polishing, turning ,power coating, mill finish etc
5.Equipment: CNC ,extruding machine, cold drawn machine, heating oven, straightening machine, cutting machine
6. STANDARD PACKING:Wooden case/carton
7. Trade Terms
1) Payment: 30% T/T in advance, 70% balance pay before delivery. L/C at sight.
2) Delivery time: 20 days after deposit receiverd. If opening mould, plus 7-10 days.
3) Trade Term can be chosen depending on your requirements.
4) FOB Port: Shanghai
3000 Series Aluminum Bar,Aluminum Bar,Aluminum Flat Bar,Aluminium Round Bar
Changzhou YiFei Machinery Co., Ltd. , https://www.yifeialu.com