A simplified way to determine the early warning thresholds of the earthquake in high -speed railways

The car model consists of one car body, two Arabs, and the four wheels groups, and a total of seven rigid bodies. The vehicles and the body of the car are connected to the secondary springs, while the vehicles and wheel groups are connected to the initial springs. Each rigid body has five degrees of freedom, which is transverse movement, vertical movement, wrapping, stadium, and yao. Thus, the system of the entire 3D vehicle model has 35 degrees of freedom. In addition, both the primary and secondary springs and clothes models are simulated using pro -manner spring elements. The car model parameters are mentioned in Table 5.

Table 5 follow the upper structure parameters.

In the form, the interaction between the wheel and the railway is simulated by applying the pairs of communication. The spatial dynamic contact force model for the interaction between the wheels consists of two parts: the exact force calculation model and the regular power calculation model. The transverse force uses the “penalty function” method for the account, while controlling the friction coefficient of the contact surface on 0.3. Ordinary power continues to use the “Hertz” communication method to analyze the form. The method of inserting the seismic wave is the same as previously shown, and a diagram of the 3D model appears in Figure 9.

Figure 9

A side display of the component vehicle path model is created (Figure 9 with 51).

In the dynamic model, the inner wheel diameter is 845 mm, the outer diameter is 915 mm, and its thickness is 145 mm. The steel railways depend on standard railway 60, with a railway railway of 176 mm, a lesser width of 150 mm, the upper width of 73 mm, and the web thickness of 16.5 mm. The steel bars scale are taken as 1435 mm according to the specifications, the distance between the wheels on the same axis is 100 mm, the length of the track is 2000 meters, and the length of the track board is 5 meters, with a total of 400 track panels. The “tie” restrictions are applied between the track panels, and the track panels are placed under solid bars as a concrete structure. Both steel bars, tracking panels, and installation models adopt a linear, linear, flexible model, as shown in Table 3.

Form analysis and health verification

In this section, a seismic wave is used to accelerate the pipe with a period of five sessions and a capacity of 0.3 grams as seismic inputs, as shown in Figure 22. The vertical force is calculated between the wheel and the railway, the horizontal train between the wheel and the railway, the wheel lifts, the horizontal pressure between the wheel, the iron rail and the railway below the different train. Violations are not considered the path. The train speeds are considered 100 km/h, 200 km/h, and 300 km/hour. The calculated results are compared to the results of the above -mentioned vibration schedule experiments, as shown in figs. 10, 11, 12, 13, 14.

Figure 10

A comparison between the vertical wheel forces between the results of the test and the results of the account.

Figure 11

Compare the forces of the horizontal wheel track between the test results and the results of the account.

Figure 12

Comparing the wheel raising between the test results and the results of the account.

Figure 13

Comparing the horizontal relative displacement between the results of the test and the results of the account.

Figure 14

Pocket seismic waves.

As shown in figs. 10, 11, 12, 13, 14, under seismic work and in the absence of path violations, vertical force curves between the wheel and railway, the horizontal force between the wheel and the railway, the amount of the wheel lifting, and the relative horizontal clarification between the wheel and the railway, and displays almost similar trends when the train ranges at a speed of 100 km/H. This result indicates that the effect of the train speed on the dynamic response to the wheel housing system is relatively small under seismic work when the path violations are not considered.

Moreover, the results of numerical simulations are compared to the results of the experiments of the fixed model fly. Although there are slight differences in detail, the peak values ​​and overall wave forms of the two groups of results are mainly consistent. This also shows that the dynamic response to the railway system when the train is fixed under seismic work soon when the train travels at a constant speed on the path without considering tracking violations. This not only verifies the authenticity of the numerical model, but also provides strong and reference to numerical simulation, taking into account the path violations in the next section.

Create an irregular course of the path

The American track spectrum is widely applied in a high -speed rail study in China. In this section, the opposite conversion method is used to simulate playing on the American track. Based on the function of the spectral density of energy for the irregularity of the American track, the wavelength range is set for the regularity of the path from 2 to 50 meters. Matlab programming is used to draw the American 6 -level track spectrum, as shown in figs. 15 and 16, which represent vertical and directional isolation, respectively. According to the results of numerical simulation, the scope of the vertical irregular isolation capacity in the American level of 6 is [− 4, 4] (Units: mm); The scope of irregular direction is also [− 4, 4] (Units: mm).

Figure 15. 16

Spectrum direction of the irregular path.

In the program network unit, the network density is used for the path to determine the accuracy of miles. Then the state of irregularity is achieved by adjusting the coordinates positions of the track elements. Due to the large number of route elements, the programming approach is adopted to apply irregular spectrums in both vertical and directional trends on the 3D vehicle path model. Figure 17 shows the form of the path model after adding.

Figure 17

Violations tracking details (Figure 17 using 51) were created.

The dynamic response to the railway, given the irregularity of the track

For more investigation into the relationship between the speed of the car and the dynamic response to the railway in light of the work of seismic forces after the enforcement of the track violations, the seismic waves are still as inputs of the ground movement. Vertical railway power, horizontal railway power, wheel lifting, and horizontal railway displacement of the car at different speeds after entering the path violations. Car -looked speeds are 100 km/h, 200 km/h, 250 km/h, 300 km/h, 350 km/hour, 400 km/hour. Due to the patterns of the dynamic response similar to the four wheels groups, and for brevity, the peak dynamic response curves for the vertical railway power, the strength of the horizontal wheel, the lifting of the wheels, and the removal of the horizontal wheels of one group of wheels shown in shapes. 18, 19, 20, 21. It can be seen that when considering the path violations, under the action of the earthquake, the effect of the different car speeds on the dynamic response to the railway is very clear.

Figure 18

The peak response of the vertical force.

Figure 19

The peak response of the horizontal wheel force.

Figure 20

The peak response of the wheel lifting.

Figure 21

Responding to the peak of the relative horizontal displacement wheels.

From figs. 18, 19, 20, 21, it can be observed that with the speed of the train, the response of the peak of the vertical force of the railway does not grow in linear but it fluctuates within the range of (150-175 kW). It is worth noting, at a speed of a train of 300 km/h, the response of the peak corresponding to the vertical force is the smallest, at 150 kilometers. The peak response to the horizontal force of the railway fluctuates within the limits of (75-100 km), with the largest peak response that occurs at a train at a train of 300 km/h, up to 100 km. The peak response to lifting the wheels fluctuates within the range of (4.5-6 mm), with the smallest response of a peak that meets the speed of a train of 250 km/h at 4.7 mm. The peak response to the relative horizontal displacement fluctuates between the wheel and the railway within a smaller range of (3.4-4.2 mm).

In general, when the seismic wave peak is 0.3 g, the extent of the wavelength of the regular path (0.5 to 80 meters), and the extent of the car speed (100-400 km/h), and there is no effect on the speed of the car on the peak values ​​for the various dynamic responses of the wheel, and there is no clear linear growth direction. Therefore, it can be concluded that in a specific range, vehicle deviation is not associated with seismic work significantly at the speed of the car.

Looking at the operating status of vehicles under seismic work as a car overheat that works on irregular tracks and vehicles that work on smooth tracks under seismic procedures, railway forces when the car operates on a smooth straight path can be almost equivalent to wheel forces when the car is fixed. The dynamic response to the path of fixed vehicles can be verified under the seismic procedure by testing the tremor, as mentioned earlier. The main disadvantage is that in reality, the work vehicle and seismic work may have a conjunction effect. However, the analysis of the aforementioned research indicates that the deviation from peace under seismic work is not closely related to the speed of the car. Therefore, the above -mentioned approach can be used as a preliminary approximation to determine the early seismic alarm threshold, providing some theoretical support for subsequent research on early seismic alarm thresholds of high -speed railways.

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