Dynamic loading test equipment for icy and snowy road surfaces

Abstract

This invention relates to a dynamic loading experimental device for icy and snowy road surfaces, belonging to the technical field of road surface loading experimental equipment. It includes: a loading device placed on the ground to apply load to a wheel assembly, simulating vehicle loading; a wheel assembly mounted on the loading device; and a turntable positioned below the wheel assembly, capable of rotation to simulate vehicle movement. This invention can be applied to simulate the generation of road surface ripples under specific snowfall environments and load conditions using different road surface materials. It can enable the development of corresponding traffic control schemes based on experimental results or provide fundamental theoretical support for removing "snow washboard" ripples, overcoming the shortcomings of existing equipment being large-scale and difficult to implement. The loading device used in this invention can eliminate the risk of the loaded weight becoming unstable and falling during the experiment; the use of a ring-shaped experimental device makes the applied load more realistic; and the innovative design of a nested spring structure achieves constant force application and solves the problem of fixed displacement that may occur during previous loading methods.

Description

Technical Field

[0001] This invention belongs to the technical field of road surface loading test equipment, specifically relating to a dynamic loading test equipment for icy and snowy road surfaces. Background Technology

[0002] Existing road loading devices alter the load applied to the road surface and thus change the load vibration frequency by applying weights of varying weights. For example, the paper "Fundamental study on spontaneous corrugation pattern on dry sand due to moving vehicle" discloses a "static loading experimental device" that changes the natural frequency by placing weights of different weights above a spring to vary the applied load. This loading method has drawbacks. Because the weights are fixed above the spring, they may fall at excessive speeds or with large vibration amplitudes, posing a significant safety hazard. Furthermore, the weights are fixed, limiting the range of loads that can be applied. Another example is reciprocating moving loading devices, which exhibit poor continuity in applying loads to the road surface, resulting in a discrepancy with actual road surface loads, and the load magnitude cannot be controlled.

[0003] In addition, when a heavy object is loaded, the force exerted on the wheel due to the impact of the road surface may cause the weight of the object above the second spring to be insufficient, resulting in the wheel moving upward and causing the load to change or even lift off the ground, thus making it impossible to achieve a constant load. Summary of the Invention

[0004] In order to solve the above problems, the present invention provides a dynamic loading experimental device for ice and snow roads.

[0005] The technical solution adopted in this invention is:

[0006] A dynamic loading test device for icy and snowy road surfaces includes:

[0007] The control cabinet connects to the loading device and turntable, and controls the operation of the loading device and turntable, as well as data acquisition.

[0008] A loading device is placed on the ground and applies a load to the wheel assembly to simulate vehicle loading;

[0009] Wheel assembly, mounted on the loading device;

[0010] A turntable, located below the wheel assembly, can rotate to simulate vehicle movement.

[0011] Compared with the prior art, the present invention has the following advantages:

[0012] 1. This invention is a road surface indoor loading test system, which can be applied to simulate the generation of road surface ripples under specific snowfall environment and load conditions for different road surfaces. It can realize the formulation of corresponding traffic control schemes or provide basic theoretical support for removing "snow washboard" by means of experimental results, and solves the shortcomings of existing equipment being large-scale and difficult to implement experiments.

[0013] 2. The loading device used in this invention can solve the risk of the loaded weight becoming unstable and falling during the experiment; the vertical setting of the laser sensor solves the problem of refraction of the laser displacement sensor on the ice surface when measuring the smoothness of icy and snowy roads (transparent objects usually scatter some light; by increasing the scattering characteristics of the transparent object's surface, the laser beam can be scattered and measured within the sensor's range. Increasing the scattering characteristics of the transparent object's surface can be achieved by introducing a small roughness or using a surface treatment agent). This invention can solve the problem of uneven traffic density during loading; the ring-shaped experimental device makes the applied load more realistic; the innovative nested spring structure solves the problem of constant force when applying force and solves the problem of fixed displacement that may occur during previous loading; the improved support frame, load distribution system, and connection mechanism increase the overall stability.

[0014] 3. This invention utilizes a pressure sensor to change the magnitude of the load applied to the road surface in real time, and the applied load can be arbitrarily controlled with a large adjustable range, enabling effective control of the load. Furthermore, it removes heavy objects, avoiding the danger caused by falling weights.

[0015] 4. Compared to the reciprocating movement mode, the method of generating relative displacement by rotating the bottom turntable applies a load to the road surface once when the turntable rotates once. Furthermore, by controlling the turntable speed to simulate the vehicle speed, the continuity and uniformity of load application are ensured, which can effectively simulate the dynamic loading of icy and snowy road surfaces. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the present invention;

[0017] Figure 2 This is a schematic diagram of the dynamic loading oscillation component structure of the present invention;

[0018] The components include: 1. Control cabinet; 2. Loading device; 3. Wheel assembly; 4. Turntable; 5. Upper laser sensor; 6. Lower laser sensor; 7. Ultrasonic sensor; 8. Temperature sensor 1; 9. Adjusting threaded rod; 10. Ice and snow adding device; 21. Telescopic upper crossbeam; 22. Scaffolding; 23. Telescopic middle crossbeam; 24. Loading cylinder; 25. Upper pressure sensor; 26. Dynamic loading oscillation assembly; 27. Lower pressure sensor; 261. Upper connecting rod; 262. Replaceable spring assembly; 263. Lower connecting rod; 2621. Upper flange; 2622. Upper sleeve; 2623. Spring; 2624. Lower sleeve; 2625. Lower flange; 2626. Outer sleeve; 41. Outer ring baffle; 42. Inner ring baffle; 43. Chassis; 44. Drive device; 441. Drive motor; 442. Base frame; 443. Support wheel; 444. Foot. Detailed Implementation

[0019] To better understand the purpose, structure, and function of this invention, the invention will be described in further detail below with reference to the accompanying drawings.

[0020] Reference Figure 1 , Figure 2 As shown, a dynamic loading experimental device for simulating vehicle loading on icy and snowy road surfaces, set up on the ground, includes:

[0021] Control cabinet 1 is connected to loading device 2 and turntable 4 and controls the operation of loading device 2 and turntable 4 and data acquisition;

[0022] Loading device 2 is placed on the ground and applies a load to wheel assembly 3 to simulate vehicle loading;

[0023] Wheel assembly 3 is mounted on loading device 2;

[0024] Turntable 4, located below wheel assembly 3, can rotate to simulate vehicle movement, rotating at a constant rate.

[0025] The loading device 2 includes a telescopic upper crossbeam 21, a telescopic middle crossbeam 23, a scaffold 22, a loading cylinder 24, a dynamic loading oscillation assembly 26, an upper pressure sensor 25, and a lower pressure sensor 27. One end of the telescopic upper crossbeam 21 and the telescopic middle crossbeam 23 is connected to the scaffold 22, and the other end of the telescopic upper crossbeam 21 and the telescopic middle crossbeam 23 is connected to the vertically arranged loading cylinder 24 and the vertically arranged dynamic loading oscillation assembly 26, respectively, forming an "H"-shaped structure. Both the telescopic upper crossbeam 21 and the telescopic middle crossbeam 23 adopt a sleeve-type telescopic structure and are fixed by a set screw. The upper pressure sensor 25 is connected between the lower end of the loading cylinder 24 and the upper end of the dynamic loading oscillation assembly 26, and the lower pressure sensor 27 is connected between the lower end of the dynamic loading oscillation assembly 26 and the wheel assembly 3.

[0026] The dynamic loading oscillation assembly 26 includes an upper connecting rod 261, a replaceable spring assembly 262, and a lower connecting rod 263; the upper pressure sensor 25 and the lower pressure sensor 27 are connected in sequence by the upper connecting rod 261, the replaceable spring assembly 262, and the lower connecting rod 263, and the replaceable spring assembly 262 is installed on the telescopic middle crossbeam 23.

[0027] The replaceable spring assembly 262 includes a spring 2623, an upper sleeve 2622, a lower sleeve 2624, an upper flange 2621, a lower flange 2625, and an outer sleeve 2626. The upper sleeve 2622, spring 2623, and lower sleeve 2624 are connected sequentially between the upper connecting rod 261 and the lower connecting rod 263. The spring 2623 is used to simulate the vehicle's shock absorption system, and the upper and lower ends of the spring 2623 are inserted into the upper sleeve 2622 and the lower sleeve 2624, respectively. The nested spring 2623 in the middle realizes the simulation of the vehicle and avoids the instability of the previous fixed displacement loading force. The outer sleeve 2626 is fitted on the outside of the upper sleeve 2622, the lower sleeve 2624, and the spring 2623 to prevent axial displacement. The outer surface of the outer sleeve 2626 is fixed to the telescopic middle crossbeam 23. The upper and lower ends of the outer sleeve 2626 are connected to the upper flange 2621 and the lower flange 2625 respectively. The upper connecting rod 261 and the lower connecting rod 263 slide through the upper flange 2621 and the lower flange 2625 respectively.

[0028] The wheel assembly 3 includes a wheel and a wheel frame; a proportionally scaled-down wheel is rotatably mounted on the wheel frame, and the wheel frame is connected to the pressure sensor 27 of the loading device.

[0029] An electric heating device is installed on the wheel of wheel assembly 3.

[0030] The dynamic loading test equipment for ice and snow road surfaces also includes an upper laser sensor 5, a lower laser sensor 6, an ultrasonic sensor 7, a temperature sensor 1 8, and a temperature sensor 2.

[0031] The upper laser sensor 5 and the lower laser sensor 6 are respectively mounted on the outer sleeve 2626 of the loading device via a sensor mounting plate, and are used to measure changes in road surface height.

[0032] The ultrasonic sensor 7 is mounted on the wheel frame of the wheel assembly 3 via the sensor mounting plate 2, and is used to measure the surface smoothness parameters of icy and snowy roads.

[0033] Temperature sensor 8 is positioned facing the wheel and mounted on sensor mounting plate 2 via adjusting threaded rod 9. Sensor mounting plate 2 is mounted on wheel frame of wheel assembly 3 for monitoring wheel temperature.

[0034] Temperature sensor 2 is installed on turntable 4 to monitor road surface temperature.

[0035] The turntable 4 includes an inner ring baffle 42, an outer ring baffle 41, a chassis 43, and a drive device 44. The inner ring baffle 42 and the outer ring baffle 41 are concentrically mounted on the chassis 43 to form a circular track. The wheel assembly 3 is placed in the circular track. The chassis 43 is driven to rotate by the drive device 44. The chassis 43 can be disassembled to replace the experimental road surface with different materials.

[0036] The drive unit 44 includes a drive motor 441, a base frame 442, multiple support wheels 443, and multiple feet 444. The drive motor 441 is detachably driven connected to the center of the bottom surface of the chassis 43. The drive motor 441 is mounted on the base frame 442. Multiple support wheels 443 are installed between the chassis 43 and the base frame 442 to support the chassis 43 and facilitate the rotation of the chassis 43. Multiple feet 444 are installed on the base frame 442.

[0037] The drive motor 441 is a forward and reverse motor to enable the chassis 43 to rotate clockwise and counterclockwise.

[0038] The outer ring baffle 41 is made of transparent plexiglass, which can be used to observe the changes in the ice and snow conditions of the road surface during the experiment. The inner ring baffle 42 is made of stainless steel. By using inner ring baffles 42 with different radii, the width of the experimental road surface can be changed. The chassis 43 is made of simulated road surface material.

[0039] The circular track of turntable 4 is used to add ice and snow through the ice and snow adding device 10 to simulate an icy and snowy road surface. The ice and snow adding device 10 can be a container with multiple holes.

[0040] The dynamically loaded oscillation assembly 26 controls the natural frequency of the oscillation. Spring 2623 facilitates the vertical vibration of the wheel. The natural frequency of the oscillation can be determined by applying an appropriate load. Before rotating the circular track, the dynamically loaded oscillation assembly 26 is set to a state of force equilibrium, with the bottom edge of the wheel lightly contacting the flat surface of the chassis 43 of the road material, with almost no pressure on the surface. Even after the circular track begins to rotate, the dynamically loaded oscillation assembly 26 can vibrate freely while maintaining force equilibrium. Initially, the self-rotating circular track is rotated at a slow speed of 3 rpm for 2 minutes, and it is confirmed that the dynamically loaded oscillation assembly 26 maintains the same position on the flat surface without vibration. Then, the rotation speed is increased to the experimental value without stopping the rotation, and the track is kept rotating continuously for at least 7 minutes.

[0041] Changes in road surface height were measured using a laser displacement sensor. After the experiment, the recorded data were analyzed using a fast Fourier transform to study the amplitude and wavelength of the ripples.

[0042] The most challenging aspect of this experiment was ensuring a smooth road surface as the initial condition. For the first two minutes of slow rotation at 3 rpm, it was crucial to confirm that the dynamically loaded oscillating component 26 was not vibrating. In all experimental cases, the dynamically loaded oscillating component 26 moved slightly vertically according to the road surface, but for the first two minutes, it completely repeated the vertical motion to reveal the original ripples of the road surface.

[0043] The inner and outer diameters of chassis 43 are as follows: the diameter is reduced by five times from one to two meters, which is equivalent to 3 m / s, meaning the speed is six times that of the original. Therefore, the required diameter is 1.5 m, and the groove width is 6 cm (the inner ring can be replaced). The outer wall of the groove is made of transparent material. Chassis 43 must be made of solid material.

[0044] The annular track groove surface in contact with the wheels is replaceable. The dimensions are based on the smallest diameter inner wall, or can cover the entire chassis 43.

[0045] Chassis 43 speed: The speed can be controlled from 3r / min down to 0, and the maximum speed of 20r / min fully meets the requirements.

[0046] Wheel requirements: The wheels should be able to lock their direction or rotate (diameter 12-16cm, width 4cm, 5x reduction), and should be electrically heated.

[0047] Sensor requirements: Vertical displacement is still measured using a laser sensor. The selection includes a 900nm TOF module, such as the ZLTA05 from Zhenshang, and the ZLDS100-4, which is designed for measuring the displacement of transparent objects. The ZLTD18 is the most suitable laser sensor for measuring glass displacement and thickness.

[0048] Temperature sensor: DSP100 series road inspection temperature sensor (+-0.28 degrees Celsius).

[0049] Pressure sensor: A pressure sensor must be installed on the vertical column.

[0050] The horizontal axis is retractable and lockable.

[0051] Requirements for spring 2623: Spring 2623 with different elastic coefficients can be replaced, or it can be replaced with a cylinder.

[0052] Loading requirements: 160N, 16kg vertical load, i.e., the vertical axis can be loaded with a load of 0-20kg, which is controllable.

[0053] Snow is added during operation: hourglass, cylindrical container, round porous hourglass.

[0054] The equipment is designed to be detachable as a whole, with connecting parts.

[0055] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A dynamic loading experimental device for icy and snowy road surfaces, characterized in that: include: The control cabinet (1) is connected to the loading device (2) and the turntable (4) and controls the operation of the loading device (2) and the turntable (4) and data acquisition. The loading device (2) is placed on the ground and applies a load to the wheel assembly (3) to simulate vehicle loading; The wheel assembly (3) is mounted on the loading device (2); Turntable (4), located below wheel assembly (3), can rotate to simulate vehicle forward movement. The loading device (2) includes a telescopic upper crossbeam (21), a telescopic middle crossbeam (23), a scaffold (22), a loading cylinder (24), a dynamic loading oscillation assembly (26), an upper pressure sensor (25), and a lower pressure sensor (27). One end of the telescopic upper crossbeam (21) and the telescopic middle crossbeam (23) is connected to the scaffold (22), and the other end of the telescopic upper crossbeam (21) and the telescopic middle crossbeam (23) is connected to the vertically arranged loading cylinder (24) and the vertically arranged dynamic loading oscillation assembly (26), respectively. An upper pressure sensor (25) is connected between the lower end of the loading cylinder (24) and the upper end of the dynamic loading oscillation assembly (26), and a lower pressure sensor (27) is connected between the lower end of the dynamic loading oscillation assembly (26) and the wheel assembly (3). The dynamic loading oscillation assembly (26) includes an upper connecting rod (261), a replaceable spring assembly (262), and a lower connecting rod (263); the upper pressure sensor (25) and the lower pressure sensor (27) are connected in sequence by the upper connecting rod (261), the replaceable spring assembly (262), and the lower connecting rod (263), and the replaceable spring assembly (262) is mounted on the telescopic middle crossbeam (23). The replaceable spring assembly (262) includes a spring (2623), an upper sleeve (2622), a lower sleeve (2624), an upper flange (2621), a lower flange (2625), and an outer sleeve (2626); the upper connecting rod (261) and the lower connecting rod (263) are connected in sequence by the upper sleeve (2622), the spring (2623), and the lower sleeve (2624), the spring (2623) is used to simulate the vehicle shock absorption system, and the upper and lower ends of the spring (2623) are respectively inserted into the upper sleeve (2624). Inside the upper sleeve (2622) and the lower sleeve (2624), the outer sleeve (2626) is fitted on the outside of the upper sleeve (2622), the lower sleeve (2624) and the spring (2623). The middle part of the outer surface of the outer sleeve (2626) is fixed on the telescopic middle crossbeam (23). The upper and lower ends of the outer sleeve (2626) are connected to the upper flange (2621) and the lower flange (2625) respectively. The upper connecting rod (261) and the lower connecting rod (263) slide through the upper flange (2621) and the lower flange (2625) respectively.

2. The dynamic loading experimental device for ice and snow road surfaces according to claim 1, characterized in that: An electric heating device is installed on the wheel of the wheel assembly (3).

3. The dynamic loading experimental device for ice and snow road surfaces according to claim 2, characterized in that: The dynamic loading test equipment for ice and snow road surfaces also includes an upper laser sensor (5), a lower laser sensor (6), an ultrasonic sensor (7), a temperature sensor one (8), and a temperature sensor two. The upper laser sensor (5) and the lower laser sensor (6) are respectively installed on the outer sleeve (2626) of the loading device for measuring changes in road surface height; The ultrasonic sensor (7) is installed on the wheel frame of the wheel assembly (3) to measure the surface smoothness parameters of the ice and snow road surface; The temperature sensor (8) is positioned facing the wheel and mounted on the wheel frame of the wheel assembly (3) for monitoring the wheel temperature; The second temperature sensor is installed on the turntable (4) and is used to monitor the road surface temperature.

4. The dynamic loading experimental device for ice and snow road surfaces according to claim 1, characterized in that: The turntable (4) includes an inner ring baffle (42), an outer ring baffle (41), a chassis (43), and a drive device (44). The inner ring baffle (42) and the outer ring baffle (41) are concentrically mounted on the chassis (43) to form a circular track. The wheel assembly (3) is placed in the circular track. The chassis (43) is driven to rotate by the drive device (44). The chassis (43) can be disassembled to replace the test road surface with different materials.

5. The dynamic loading experimental device for ice and snow road surfaces according to claim 4, characterized in that: The outer ring baffle (41) is made of transparent organic glass, which can observe the changes in the ice and snow state of the road surface during the experiment. The inner ring baffle (42) is made of stainless steel. By applying inner ring baffles (42) of different radii, the width of the experimental road surface can be changed. The chassis (43) is made of simulated road surface material.

6. The dynamic loading test device for ice and snow road surfaces according to claim 5, characterized in that: The circular track of the turntable (4) is filled with ice and snow by the ice and snow adding device (10) to simulate an icy and snowy road surface. The ice and snow adding device (10) is a container with multiple holes.

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