Rapid cooling environmental chamber for high-speed impact test of foreign matters on rail vehicle parts

Abstract

This invention belongs to the field of high-speed impact testing of rail vehicle components, and discloses a rapid cooling environmental chamber for high-speed impact testing of rail vehicle components. The chamber includes a chamber body, with one side serving as the impactor inlet. The inner walls of the other sides of the chamber are lined with liquid nitrogen condenser pipes and environmental temperature and humidity sensors. The liquid nitrogen condenser pipes are connected to a self-pressurized liquid nitrogen tank via an external channel to facilitate the conduction and delivery of the cooling medium. The impactor inlet is movably connected to the chamber frame and features an adjustable sliding mechanism. The adjustable sliding mechanism has stretchable sections connected to its left and right sides, and a disposable low-strength sealing and heat-insulating film is installed on the mechanism. The impactor inlet is located within the area of ​​this disposable low-strength sealing and heat-insulating film. A fixture for fixing the test piece is provided on the inner wall of the chamber. A high-speed camera mounting interface is located on the inner wall of the chamber, and a rotating support is located at the bottom of the chamber. This environmental chamber can rapidly achieve a preset low-temperature environment and perform multi-angle impact tests.

Description

Technical Field

[0001] This invention belongs to the field of high-speed impact testing of foreign objects on rail vehicle components, and particularly relates to a rapid cooling environment chamber required for high-speed impact testing of foreign objects on rail vehicle components under low-temperature conditions. Background Technology

[0002] The rapid development of rail vehicle technology in my country has exposed various train equipment to the risk of impacts from falling rocks, hail, and ballast, seriously affecting operational safety. Therefore, all components and materials of rail vehicles must undergo high-speed foreign object impact tests of varying degrees to ensure the impact resistance of the car body structural components. These tests are typically conducted in a laboratory environment (normal temperature). However, my country experiences numerous extreme cold weather events, and car body materials undergo a ductile-brittle transition at low temperatures, significantly reducing the structural components' resistance to foreign object impacts. This is particularly true for trains exported to high-latitude countries like Northern Europe, where the low-temperature environment will be even more challenging. Therefore, conducting high-speed foreign object impact tests on rail vehicle structural components under low-temperature conditions is crucial for ensuring the safe operation of trains in extreme cold environments.

[0003] Chinese patent application CN111157370A discloses a low-temperature collision test environment chamber for automotive body parts and its test method. The chamber includes a test chamber, first and second cameras, a cooling device, and an impact head device. The test chamber includes an impact valve and a sealing device. The cooling device includes a cooling compensation system and a cooling system. The impact head device includes a punch, a connecting rod, and a sealing sleeve. When the punch enters the impact valve, two semi-circular rings are clamped onto the sealing sleeve. However, this patent can only perform a single-angle impact test and cannot monitor the temperature and humidity uniformity of the test piece, falling far short of actual needs. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the background art above, and to provide a rapid cooling environment chamber for high-speed impact testing of foreign objects on rail vehicle components that can quickly achieve a preset low temperature environment and meet the requirements of multi-angle experiments.

[0005] To solve the above-mentioned technical problems, the technical solution proposed by the present invention is: a rapid cooling environment for high-speed impact test of foreign objects on rail vehicle components, comprising: a box body, including a frame and a sandwich insulation wall formed by a high-strength aluminum alloy panel and insulation material;

[0006] One side of the enclosure is the impactor entrance, and the inner walls of the other sides of the enclosure are lined with liquid nitrogen condensation pipes and ambient temperature and humidity sensors. The liquid nitrogen condensation pipes are connected to a self-pressurized liquid nitrogen tank through an external channel to realize the conduction and transportation of the cooling medium.

[0007] The impactor injection door is movably connected to the chamber frame, and the chamber is sealed when the impactor injection door is closed; when the impactor injection door is opened, it is used to place the test specimen in the chamber. The impactor injection door is equipped with an adjustable position sliding mechanism, and the left and right sides of the adjustable position sliding mechanism are connected to stretchable parts. The adjustable position sliding mechanism is equipped with a disposable low-strength sealing and heat insulation film, and the impactor injection port is located in the area of ​​the disposable low-strength sealing and heat insulation film.

[0008] The inner wall of the chamber is equipped with a fixture for fixing the test piece and a high-speed camera mounting interface. A temperature and humidity sensor for the test piece is pre-embedded inside the test piece.

[0009] A rotating support is located at the bottom of the housing. The rotating support includes a fixed end and a rotating end. The fixed end and the rotating end are hinged together. The rotating end is locked after rotating to a predetermined angle.

[0010] In one embodiment, the rotating support base further includes a central pin, the fixed end is hinged to the rotating end through the central pin, the rotational degree of freedom of the rotating end is 0° to 75°, and the rotating end is supported by casters;

[0011] The center pin is equipped with a bolt fastening device for locking the rotating end; the center pin is also equipped with an angle scale.

[0012] In one embodiment, the travel distance of the adjustable position sliding mechanism's inlet is: L= Where H is the vertical distance from the impact point of the test piece to the inlet plane. The angle of incidence is denoted as .

[0013] In one embodiment, the disposable low-strength sealing and heat insulation film is made of a transparent flexible material and is glued to the inlet. The thickness of the disposable low-strength sealing and heat insulation film is 0.1mm to 2mm. The material breaking strength of the disposable low-strength sealing and heat insulation film is not higher than 0.1MPa, the elongation is not more than 10%, and the disposable low-strength sealing and heat insulation film is marked with a cross center mark.

[0014] In one embodiment, the inner wall of the chamber is provided with a data acquisition harness connector for connecting an ambient temperature and humidity sensor, a strain gauge, and an auxiliary test sensor. A temperature and humidity processing unit is connected to the outside of the data acquisition harness connector. The temperature and humidity processing unit is connected to the ambient temperature and humidity sensor and the temperature and humidity sensor of the test piece, and is used to monitor the temperature and humidity difference between the ambient temperature and humidity inside the chamber and the temperature and humidity of the test piece. During the cooling process, the maximum temperature difference between the test piece and the ambient temperature inside the chamber is less than 10°C and the maximum humidity percentage difference is less than 10%.

[0015] In one embodiment, an intelligent liquid nitrogen flow control valve is installed at the outlet of the self-pressurized liquid nitrogen tank. The liquid nitrogen flow rate is adjusted in real time by receiving temperature data from the temperature and humidity processing unit. When the temperature difference between the ambient temperature inside the chamber and the temperature of the test piece is ±1℃ and the humidity difference is 2%, it is determined that the temperature and humidity of the sample are consistent with the ambient temperature and humidity.

[0016] In one embodiment, the number of temperature and humidity sensors embedded in the test specimen is no less than four, and they are respectively set at different positions on the test specimen. If the relative error of the temperature and humidity data monitored at different positions is within 2%, it is determined that the test specimen has reached a stable test state.

[0017] In one embodiment, a humidity regulator is provided on the inner wall of the box.

[0018] In one embodiment, the liquid nitrogen condenser tube is a stainless steel tube with a diameter of 3-6 mm, and is distributed in an S-shape along the inner wall of the chamber.

[0019] In one embodiment, the stretchable part is a corrugated origami structure made of flexible thermal insulation material.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: The rapid cooling environment chamber for high-speed impact testing of foreign objects in rail vehicle components provided by the present invention is installed at the bottom of the chamber body via a rotating support base. The rotating support base includes a fixed end and a rotating end, which are hinged together. The rotating end is locked after rotating at a predetermined angle. The impactor entrance gate is equipped with an adjustable position sliding mechanism and a scale. The adjustable position sliding mechanism is connected to the left and right sides with stretchable parts, so that the adjustable position sliding mechanism can move horizontally in the impactor entrance gate. The moving distance can be quickly and accurately adjusted by the incident angle value and the vertical distance of the impact of the test piece, ensuring the accuracy of the angled impact. The adjustable sliding mechanism features a disposable low-strength sealing and heat-insulating film, which not only achieves sealing and insulation of the rapid cooling environmental chamber but also minimizes energy loss from impact foreign objects and secondary damage to the test specimens from fragments. The disposable low-strength sealing and heat-insulating film has a crosshair center mark for easy aiming and verification of the impactor, injection port, and injection point before testing. The impactor injection port is located within the disposable low-strength sealing and heat-insulating film area. The adjustable sliding mechanism allows for displacement adjustment of the impactor injection port position. The rotating support and impactor injection port design enable multi-angle and multi-position impact experiments, better meeting practical needs. The disposable low-strength sealing and heat-insulating film is replaced after each test, ensuring rapid cooling within the rapid cooling environmental chamber and achieving precise control of the low-temperature environment temperature. The temperature and humidity processing unit monitors and regulates the ambient temperature and humidity within the chamber and the temperature and humidity of the test specimens, ensuring that the actual temperature of the test specimens matches the ambient temperature and improving test accuracy. In addition, the inner walls of the rapid cooling environment chamber (except for the impactor entry door) are all covered with liquid nitrogen condenser pipes and environmental temperature and humidity sensors. The liquid nitrogen condenser pipes are connected to the self-pressurized liquid nitrogen tank through the external channel of the rapid cooling environment chamber, which can efficiently and conveniently achieve a low temperature environment. The chamber includes a frame and a sandwich insulation wall formed by high-strength aluminum alloy panels and insulation materials, which can better perform low temperature environment insulation and withstand the impact force of impact tests. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of a rapid cooling environment chamber for high-speed impact testing of foreign objects in rail vehicle components, according to one embodiment.

[0023] Figure 2 This is a schematic diagram of another state of the rapid cooling environment chamber for high-speed impact testing of foreign objects in rail vehicle components, according to one embodiment.

[0024] Figure 3 This is a schematic diagram of the test piece structure according to one embodiment.

[0025] Reference numerals: 1: Rotating support base; 11: Rotating end; 12: Fixed end; 13: Caster wheel; 14: Bolt fastening device; 15: Angle scale; 2: High-speed camera; 3: Housing; 31: Wall; 32: Frame; 33: Data acquisition harness connector; 4: High-speed camera observation hole; 41: Protective glass cover; 5: Lighting equipment; 6: Liquid nitrogen condenser tube; 61: Liquid nitrogen condenser tube main connector (external channel); 7: Impact object entry door; 71: Adjustable position sliding mechanism; 711: Tensile part; 72: Ambient temperature and humidity sensor; 73: Angled high-speed camera mounting hole; 74: Disposable low-strength sealing and heat insulation film; 8: Test piece fixing fixture; 9: Test piece; 91: Test piece temperature and humidity sensor; 92: Data acquisition harness; 10: Humidity regulator. Detailed Implementation

[0026] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0027] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0028] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0029] Example:

[0030] like Figures 1-3As shown, a rapid cooling environmental chamber for high-speed impact testing of foreign objects in rail vehicle components according to one embodiment includes: a rotating support base 1 and a chamber body 3. The rotating support base 1 is located at the bottom of the chamber body 3 and includes a fixed end 12 and a rotating end 11. The fixed end 12 is fixed to the ground and is hinged to the rotating end 11. The rotational freedom of the rotating end 11 is 0° to 75°. In use, after determining the required incident angle of the specimen, the rotating end 11 is rotated to the predetermined angle and then locked. The chamber body 3 includes a frame 32 and a sandwich layer formed by a high-strength aluminum alloy layer and thermal insulation material. One side of the chamber body 3 is an impactor entrance door 7. The inner wall surface 31 of the other sides of the chamber body 3 is covered with a liquid nitrogen condenser pipe 6 and an ambient temperature and humidity sensor 72. The ambient temperature and humidity sensor 72 is used to monitor the temperature and humidity inside the chamber body 3. The liquid nitrogen condenser pipe 6 is connected to a self-pressurized liquid nitrogen tank through an external channel 61 to realize the conduction and transportation of the cooling medium. The impactor entrance door 7 is movably connected to the frame of the chamber 3, and the chamber 3 is sealed when the impactor entrance door 7 is closed. The chamber 3 contains a fixture for fixing and installing the test piece 9. When the impactor entrance door 7 is open, it is used to place the test piece 9 into the chamber 3. The impactor entrance door 7 is equipped with an adjustable position sliding mechanism 71 and a scale to determine the left and right movement distance of the adjustable position sliding mechanism 71. A high-speed camera mounting interface is installed on the inner wall of the chamber 3, and multiple mounting interfaces are possible. A temperature and humidity sensor 91 is pre-embedded inside the test piece 9 to monitor the temperature and humidity of the test piece 9 itself. The temperature and humidity sensor 91 is connected to the acquisition harness connector 33 via an acquisition harness 92.

[0031] The high-speed impact rapid cooling environment chamber for rail vehicle components provided by this invention is installed at the bottom of the chamber body 3 via a rotating support 1. The rotating support 1 includes a fixed end 12 and a rotating end 11. The fixed end 12 is fixed to the ground and hinged to the rotating end 11. The rotational freedom of the rotating end 11 is 0° to 75°, and the rotating end 11 is locked after rotating a predetermined angle. An adjustable position sliding mechanism 71 is provided on the impactor entry gate 7. The left and right sides of the adjustable position sliding mechanism 71 are connected to stretchable parts 711, so that the adjustable position sliding mechanism 71 can be adjusted in position on the impactor entry gate 7. A disposable low-strength sealing heat insulation film 74 is provided on the adjustable position sliding mechanism 71. The impactor entry port 75 is located in the area of ​​the disposable low-strength sealing heat insulation film 74. Since the adjustable position sliding mechanism 71 can be adjusted in position on the impactor entry gate 7, the position of the impactor entry port 75 is adjustable. By monitoring the ambient temperature and humidity sensor 72 on the inner wall of the chamber 3 and the temperature and humidity sensor 91 inside the test specimen 9, the temperature and humidity difference between the two can be kept within a controllable range during the cooling process. This prevents excessively rapid cooling from causing large internal temperature differences in the test specimen 9, which could lead to localized deformation or even failure, thus failing to obtain the true impact resistance performance of the specimen. Therefore, the rapid cooling environmental chamber provided by this invention, by monitoring the temperature and humidity of both the test specimen 9 and the chamber 3 and controlling the temperature and humidity difference between them, can better obtain the true results of high-speed impact tests on the test specimen 9 at different incident angles.

[0032] Specifically, in one embodiment, the enclosure 3 is generally rectangular (cube) in shape, with beam-type profiles as the skeleton 32 and sheet metal as the surface skin, manufactured through welding / riveting processes. The main materials are metal materials such as aluminum alloy or carbon steel to ensure the load-bearing capacity and impact resistance of the enclosure 3 structure. Preferably, to meet the thermal insulation requirements, the wall of the enclosure 3 is a sandwich insulation layer of high-strength aluminum alloy (carbon steel) and thermal insulation material. This satisfies both the structural strength requirements of the enclosure 3 and the thermal insulation effect required by the test environment.

[0033] Specifically, in one embodiment, the fixed end 12 of the rotating support 1 is hinged to the rotating end 11 via a central pin, and the rotating end 11 is supported by a caster wheel 13 to ensure its rotational freedom around the central pin. A bolt fastening device 14 is provided on the central pin of the rotating support 1, which is used to lock the rotating end 11, ensuring that the rotating end 11 of the rotating support 1 cannot rotate around the central pin in the locked state. An angle scale 15 is provided on the central pin of the rotating support 1. The angle scale 15 can quickly and accurately determine the rotation angle. In use, the central pin bolt fastening device 14 and the caster wheel 13 of the rotating support are unlocked, then the incident angle is adjusted, and finally the caster wheel 13 and the central pin bolt fastening device 14 are locked to ensure that the incident angle is fixed until the impact test at that angle is completed. Preferably, the rotating support 1 is welded from aluminum alloy (carbon steel) beam-type profiles.

[0034] Preferably, in one embodiment, the stretchable portion 711 is a corrugated origami structure made of flexible heat-insulating material. The adjustable position sliding mechanism 71 is provided with a disposable low-strength sealing heat-insulating film 74, and the impactor inlet 75 is located in the area where the disposable low-strength sealing heat-insulating film 74 is located. Preferably, the sliding position of the adjustable position sliding mechanism 71 through the stretchable portion 711 extends from the center point of the incident wall to the edge of the stretchable portion 711, thereby ensuring the positional requirements of the inlet when incident at an off-angle. To adapt to the impact position requirements under different incident angles, specifically, the inlet movement distance is: L = Where H is the shortest vertical distance from the impact point of the test piece to the entrance plane. The angle of incidence is denoted as .

[0035] Preferably, the disposable low-strength sealing and heat insulation film 74 is made of flexible material and is glued to the inlet. The disposable low-strength sealing and heat insulation film 74 has a thickness of 0.1mm to 2mm, a breaking strength of no more than 0.1MPa, and an elongation of no more than 10%. Under these conditions, it can be ensured that the test specimen 9 can smoothly penetrate the disposable low-strength sealing and heat insulation film 74, and the heat insulation requirements between the cooling environment inside the chamber 3 and the outside world can be guaranteed. It also allows the incident impactor to pass quickly through the impactor inlet 75 without causing speed attenuation or changes in running posture. The disposable low-strength sealing and heat insulation film 74 not only achieves sealing and heat insulation of the environmental chamber, but also minimizes the energy loss of the incident impactor and secondary damage to the test specimen 9 caused by fragments. Preferably, the disposable low-strength sealing and heat insulation film 74 is provided with a cross center mark to facilitate the aiming and verification of the incident impactor, inlet, and inlet point before the test, and to assist in aligning the impact point position of the test specimen 9 with the aiming of the impactor before it enters the chamber. Preferably, the inner wall of the impactor entrance gate 7 is provided with an obliquely placed high-speed camera mounting hole 73, and a laminated tempered glass protective cover is installed at the lens position.

[0036] By utilizing the rotating support base 1 and the impactor entrance gate 7, impact tests can be conducted at multiple angles and positions. The disposable low-strength sealing and heat insulation film 74 can be replaced after each test. This device allows for impact tests at multiple angles and positions under the same working conditions, better meeting practical needs. Furthermore, it enables rapid cooling at low temperatures.

[0037] The inner wall 31 of the environmental chamber (except for the impactor entrance door) is lined with liquid nitrogen condenser pipes 6 and environmental temperature and humidity sensors 72. The liquid nitrogen condenser pipes 6 are connected to a self-pressurized liquid nitrogen tank through an external channel 61, which can efficiently achieve low-temperature environment setting. The chamber 3 includes a frame 32 and a sandwich layer formed by a high-strength aluminum alloy layer and thermal insulation material, which better provides low-temperature environment insulation and withstands the impact force of the impact test. A humidity regulator 10 is installed on the inner wall of the chamber 3 to control the humidity inside the chamber 3. The inner wall of the chamber 3 is equipped with a data acquisition harness connector 33 for connecting the environmental temperature and humidity sensor 72, strain gauges and auxiliary test sensors (sensors are set according to different requirements, such as acceleration sensors, etc.). The external connection of the data acquisition harness connector 33 is a temperature and humidity processing unit, which is connected to the environmental temperature and humidity sensor 72 and the temperature and humidity sensor of the test piece 91, to monitor the difference between the environmental temperature and humidity inside the chamber 3 and the temperature and humidity of the test piece 9. During the cooling process, since it takes a certain amount of time for the ambient temperature inside chamber 3 to be conducted to the test specimen 9, the temperatures of both are monitored simultaneously. The maximum temperature difference between the test specimen 9 and the environment inside chamber 3 is controlled to be less than 10℃, and the maximum humidity percentage difference is controlled to be less than 10%. This prevents the ambient temperature from cooling too quickly, which could lead to localized deformation or failure of the specimen and affect the accuracy of the experiment. Preferably, when the maximum temperature difference between the test specimen 9 and the environment inside chamber 3 is 1℃ and the humidity percentage difference is 2%, the temperature and humidity of the test specimen 9 are considered to be consistent with the ambient temperature and humidity, i.e., the preset temperature and humidity conditions have been met. During temperature control, the temperature of the test specimen 9 has a higher priority than the ambient temperature inside chamber 3 in the control logic to ensure that the temperature of the test specimen 9 meets the standard. Preferably, when the area of ​​the test specimen 9 is large or its shape is complex, the number of temperature and humidity sensors 91 is no less than four, respectively set at different positions on the test specimen 9. A relative error of less than 2% in the monitoring data from different monitoring positions indicates that the test specimen 9 has reached a stable experimental state.

[0038] Specifically, in one embodiment, the impactor entrance door 7 is a fully openable structure, and the impactor entrance door 7 is connected to the frame 32 of the housing 3 via hinges. To facilitate the installation / removal of the sample 9 inside the housing 3, a rotary door lock is used for easy opening and closing.

[0039] Specifically, in one embodiment, liquid nitrogen condenser pipes 6 and ambient temperature and humidity sensors 72 are laid on the inner wall surfaces 31 of the other sides of the chamber 3. The liquid nitrogen condenser pipes 6 are connected to a self-pressurized liquid nitrogen tank through an external channel 61 to realize the conduction and transportation of the cooling medium. Preferably, the liquid nitrogen condenser pipes 6 are connected to the self-pressurized liquid nitrogen tank through the external channel 61 and automatically adjust the liquid nitrogen flow rate in real time according to temperature changes to control the temperature inside the chamber. Preferably, the liquid nitrogen condenser pipes 6 are stainless steel pipes with a diameter of 3-6 mm, distributed in an S-shape along each inner wall surface and finally converging at the external channel 61 to connect with the self-pressurized liquid nitrogen tank. Preferably, the layout of the liquid nitrogen condenser pipes 6 on each wall surface is optimized using thermal-fluid coupling analysis technology, and the maximum cooling rate can reach 20℃ / min, which can greatly improve the heat exchange efficiency and rate of the liquid nitrogen condenser pipes 6, reduce the amount of liquid nitrogen used, and reduce the experimental cost. Preferably, the liquid nitrogen tank outlet is equipped with an intelligent liquid nitrogen flow control valve, which automatically adjusts the liquid nitrogen flow in real time by connecting to the ambient temperature and humidity sensor 72 of the housing 3, thereby reducing and stabilizing the temperature inside the housing 3, with a temperature control accuracy of ±0.5℃.

[0040] Before the internal environment of chamber 3 reaches the preset stable test temperature and humidity (cooling stage), the temperature and humidity are regulated by connecting an intelligent liquid nitrogen flow control valve and a humidity regulator 10 through a temperature and humidity processing unit. The maximum temperature difference between the test piece 9 and the internal environment of chamber 3 is less than 10℃, and the maximum humidity percentage difference is less than 10%, ensuring the stability and accuracy of the experimental results. Using liquid nitrogen as a cooling medium can not only greatly improve the test cooling efficiency, but also significantly reduce the test cost, thus making it more suitable for low-temperature safety protection tests of rail vehicle components. Preferably, a non-circulating cooling method is used to conduct external liquid nitrogen into the chamber through pipelines for heat exchange before it flows out. The minimum ambient temperature can reach 150℃, which can not only fully meet the extreme low-temperature environment requirements of rail vehicle components, but also greatly reduce the test cost.

[0041] Specifically, in one embodiment, the chamber 3 is equipped with dedicated lighting equipment. Multiple walls of the chamber 3, including the incident wall, side walls, and back wall, are pre-fabricated with dedicated mounting interfaces for high-speed cameras, and laminated tempered glass protective covers are installed at the lens positions to meet the observation requirements during the experiment. The rapid cooling environment chamber is equipped with flexible, sealed cable trays to facilitate the passage of data acquisition and transmission lines from various sensors.

[0042] When conducting high-speed impact tests on rail vehicle components in low-temperature environments, the chamber 3 is fixed to the impact side of the high-speed impact test system via a rotating support 1, at a distance of 3-5m from the launch tube port. The rail vehicle component to be impacted is clamped in the test component mounting position inside the chamber 3. Data acquisition sensors, such as strain gauges and displacement gauges, are arranged on the impacted component, and the acquisition lines are connected to the data acquisition system through flexible sealed cable slots. The impactor entrance gate 7 is closed and locked, and the adjustable position sliding mechanism 71 is adjusted to align the launch tube with the component to be impacted. The impact angle is adjusted via the rotating support 1, and the caster wheel 13 is locked. A high-speed camera lens is installed on the wall of the chamber 3 and connected to the acquisition system. The lighting equipment inside the chamber 3 is turned on, and the acquisition frame and parameters are adjusted. The liquid nitrogen condenser pipe 6 of the chamber 3 is connected to the self-pressurized liquid nitrogen tank via a delivery pipe. The ambient temperature inside the chamber is set, and the intelligent liquid nitrogen flow control valve is opened. The liquid nitrogen flow is controlled in real time by temperature until the preset temperature is reached and the temperature is maintained at a basically consistent level throughout the test.

Claims

1. A rapid cooling environmental chamber for high-speed impact testing of foreign objects in rail vehicle components, characterized in that, include: The enclosure includes a frame and a sandwich-insulated wall surface formed by high-strength aluminum alloy panels and insulation material; One side of the enclosure is the impactor entrance, and the inner walls of the other sides of the enclosure are lined with liquid nitrogen condensation pipes and ambient temperature and humidity sensors. The liquid nitrogen condensation pipes are connected to a self-pressurized liquid nitrogen tank through an external channel to realize the conduction and transportation of the cooling medium. The impactor injection door is movably connected to the chamber frame, and the chamber is sealed when the impactor injection door is closed; when the impactor injection door is opened, it is used to place the test specimen in the chamber. The impactor injection door is equipped with an adjustable position sliding mechanism, and the left and right sides of the adjustable position sliding mechanism are connected to stretchable parts. The adjustable position sliding mechanism is equipped with a disposable low-strength sealing and heat insulation film, and the impactor injection port is located in the area of ​​the disposable low-strength sealing and heat insulation film. The inner wall of the chamber is equipped with a fixture for fixing the test piece and a high-speed camera mounting interface. A temperature and humidity sensor for the test piece is pre-embedded inside the test piece. A rotating support is located at the bottom of the housing. The rotating support includes a fixed end and a rotating end. The fixed end and the rotating end are hinged together. The rotating end is locked after rotating to a predetermined angle. The rotating support also includes a central pin, and the fixed end is hinged to the rotating end through the central pin. The rotational degree of freedom of the rotating end is 0° to 75°, and the rotating end is supported by casters. The center pin is equipped with a bolt fastening device for locking the rotating end; the center pin is also equipped with an angle scale. The adjustable position sliding mechanism's inlet travel distance is: L= Where H is the vertical distance from the impact point of the test piece to the inlet plane. The angle of incidence is denoted as .

2. The rapid cooling environmental chamber for high-speed impact testing of foreign objects in rail vehicle components according to claim 1, characterized in that, The disposable low-strength sealing and heat insulation film is made of transparent flexible material and is glued to the injection port. The thickness of the disposable low-strength sealing and heat insulation film is 0.1mm to 2mm. The material breaking strength of the disposable low-strength sealing and heat insulation film is not higher than 0.1MPa, and the elongation is not more than 10%. The disposable low-strength sealing and heat insulation film is marked with a cross center mark.

3. The rapid cooling environmental chamber for high-speed impact testing of foreign objects in rail vehicle components according to claim 1, characterized in that, The inner wall of the chamber is equipped with a data acquisition harness connector for connecting an ambient temperature and humidity sensor, strain gauges, and auxiliary test sensors. The external connection of the data acquisition harness connector is a temperature and humidity processing unit, which is connected to the ambient temperature and humidity sensor and the temperature and humidity sensor of the test piece. It is used to monitor the temperature and humidity difference between the ambient temperature and humidity inside the chamber and the temperature and humidity of the test piece. During the cooling process, the maximum temperature difference between the test piece and the ambient temperature inside the chamber is less than 10℃, and the maximum humidity percentage difference is less than 10%.

4. The rapid cooling environmental chamber for high-speed impact testing of foreign objects in rail vehicle components according to claim 3, characterized in that, The self-pressurized liquid nitrogen tank outlet is equipped with an intelligent liquid nitrogen flow control valve. It adjusts the liquid nitrogen flow in real time by receiving temperature data from the temperature and humidity processing unit. When the temperature difference between the ambient temperature and the test specimen inside the chamber is ±1℃ and the humidity difference is 2%, it is determined that the temperature and humidity of the sample are consistent with the ambient temperature and humidity.

5. The rapid cooling environmental chamber for high-speed impact testing of foreign objects in rail vehicle components according to claim 3 or 4, characterized in that, The test piece shall have no fewer than four temperature and humidity sensors, which shall be set at different locations on the test piece. If the relative error of the temperature and humidity data monitored at different locations is within 2%, the test piece shall be deemed to have reached a stable test state.

6. The rapid cooling environmental chamber for high-speed impact testing of foreign objects in rail vehicle components according to claim 5, characterized in that, The inner wall of the box is equipped with a humidity regulator.

7. The rapid cooling environmental chamber for high-speed impact testing of foreign objects in rail vehicle components according to claim 1, characterized in that, The liquid nitrogen condenser tube is made of stainless steel with a diameter of 3-6 mm, and is distributed in an S-shape along the inner wall of the chamber.

8. The rapid cooling environmental chamber for high-speed impact testing of foreign objects in rail vehicle components according to claim 1, characterized in that, The stretchable part is a corrugated origami structure made of flexible heat-insulating material.

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