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Modeling and simulation analysis of tramcar collision process

1 Preface

in order to reduce or avoid the occurrence of sports car accidents in inclined shafts and lanes and ensure the safety of mine hoisting and transportation, according to the requirements of "coal mine safety regulations", sports car protective devices must be set on the inclined shaft transportation line. The bumper is an important part of the sports car protection system, and its reasonable design is directly related to the performance of the sports car protection device. The design and calculation of the bumper is relatively complex, because during the braking process, the tramcar produces a huge collision force on the bumper, and the collision force changes dramatically with time, so it is difficult to describe its characteristics with traditional methods. Usually, the component force of the gravity on the tramcar along the track direction multiplied by the amplification factor is calculated as the collision force, and the collision force is assumed to be constant, simplifying the dynamic process into a static process. Taking the rigid bumper as an example, this paper applies simulation software/to dynamically simulate the collision process between the mine car and the rigid bumper, so as to reveal the collision mechanism between the mine car and the rigid bumper, and provide the main parameters for the design of sports car protective devices

2. The establishment of the mechanical model

the experimental data show that the collision principle between the mine car and the rigid bumper is shown in Figure 1. According to the actual working conditions, the collision force between the tramcar and the bumper is very large, so the component force of the gravity on the tramcar along the track direction and the friction between the track and the wheel can be ignored. Collision can be considered as a special form of vibration, and the collision force is the exciting force of the bumper vibration

the impact of the tramcar on the rigid bumper can be simplified as the transverse impact of a simple supported beam with equal cross-section of particles. During the collision, the central principal inertia axis of each section of the bumper is in the same plane, and the collision force is also in this plane. The bumper vibrates laterally in this plane, and the main deformation of the bumper is bending deformation. In order to simplify the model, the shear deformation of the bumper and the moment of inertia of the section around the neutral axis in this process are ignored. According to the above analysis, the bumper can be simplified as a Bernoulli Euler beam with constant section. The mechanical model is shown in Figure 2

3. Establishment of mathematical model

according to the above established mechanical model, y (x, t) the transverse displacement of the section on the bumper from the origin x at time t, and the dynamic differential equation of the bumper is

because each point on the bumper moves synchronously in the collision process, so

replace formula (2) into formula (1), and get

according to the actual working conditions, the force of the tramcar on the rigid bumper is a concentrated force, which is expressed as a uniformly distributed force by function

4 Simulation results and analysis

based on the above established mechanical and mathematical models, establish a Simulink simulation model. Substitute the simulation parameters shown in Table 1 into the established simulation model for simulation

the tramcar with a cargo load of 1000kg, 2000kg and 3000kg collided with the rigid bumper at a speed of 15m/s. From the change curve of the collision force with time, it can be seen that the maximum collision force between the tramcar and bumper of the above three masses increased with the increase of the tramcar mass. The equipment was not used for a long time. Some users did not need to test materials at that time, and the collision time increased with the increase of the tramcar mass. The collision process between the tramcar and the bumper can be regarded as a vibration process of the spring mass system. The fixed circular frequency of this system

the tramcar mass increases, the system circular frequency decreases, and the system cycle will increase. Therefore, the interaction time between the tramcar and the rigid bumper will increase with the increase of the tramcar mass

the description of "requiring instruments to support 7 foreign languages" was seen in the bidding document of 1 prefecture level Municipal Food and Drug Administration with a mass of 1000kg. The tramcar collided with the rigid bumper at the initial speed of 5m/s, 10m/s, and 15m/s. From the curve of the collision force with the speed, it can be seen that the maximum collision force increases with the increase of the tramcar speed, and the initial speed does not change the circular frequency of the spring mass system, A mine car of the same mass has the same impact time with a rigid bumper at different speeds

5. Conclusion

(1) the maximum collision force of the tramcar against the rigid bumper increases with the increase of the tramcar mass and speed. The tramcars with masses of 1000kg, 2000kg and 3000kg collide with the above rigid bumper at the speed of 15m/s, and the maximum collision forces are 295.84kn, 448.26kn and 567.51kn respectively

(2) the collision time between the tramcar and the rigid bumper increases with the increase of the tramcar mass. The tramcar with the same mass collides with the bumper at different speeds, and the collision time is the same. The time of the tramcar with mass of 1000kg, 2000kg and 3000kg acting on the bumper is 0.1 respectively, and the fuel economy can be improved by 5% 18S, 0.167s and 0.204s (end)

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