Railway vehicle part foreign matter high-speed impact test method and test system in low-temperature environment

Abstract

The invention belongs to the field of high-speed impact object impact experiments of railway vehicle parts, and discloses a high-speed impact test method and system for foreign matters of railway vehicle parts in a low-temperature environment, and the system comprises a rapid cooling environment box which comprises a box body with a rotatable bottom, and an impact object incident door which can be opened and closed on one side surface of the box body, a position-adjustable sliding mechanism is arranged on the impact object incidence door, stretchable parts are connected to the left side and the right side of the position-adjustable sliding mechanism, a disposable low-strength sealing heat insulation film is arranged on the position-adjustable sliding mechanism, and a liquid nitrogen condensation pipe and an environment temperature and humidity sensor are laid on the inner walls of the other side faces of the box body; a to-be-tested piece fixing and mounting clamp is arranged on the inner wall of the box; a high-speed camera is mounted on the inner wall of the box body; during an experiment, a to-be-tested piece temperature and humidity sensor is pre-embedded in a to-be-tested piece; the box body is connected with a strain acquisition system; the system further comprises a high-pressure air cannon system. According to the environment box, a preset low-temperature environment can be quickly realized, and multi-angle impact tests can be realized.

Description

Technical Field

[0001] The invention belongs to the field of foreign body high-speed impact test of rail vehicle components, and in particular relates to a foreign body high-speed impact test method and test system for rail vehicle components in a low-temperature environment. Background Art

[0002] With the rapid development of my country's rail vehicle technology, various types of train equipment are facing the risk of impact from impact objects such as falling rocks, hail, and ballast, which seriously affects driving safety. Therefore, various components / materials of rail vehicles need to carry out different degrees of high-speed impact tests of foreign objects to ensure the impact resistance of the body structure components. The high-speed impact test of foreign objects on rail vehicle structural components is generally carried out in a laboratory environment (normal temperature), and the body material undergoes a ductile-brittle transition under low temperature conditions, which greatly reduces the ability of the structural components to resist foreign object impact. In particular, the trains exported by my country to high-latitude countries such as Northern Europe will face even worse low-temperature environments. Therefore, carrying out high-speed impact tests of foreign objects on rail vehicle structural components under low-temperature conditions is an important part of ensuring the safe operation of trains in extreme low-temperature environments.

[0003] A Chinese patent with publication number CN111157370A discloses a low-temperature collision test environment box for vehicle body parts and a test method thereof, wherein the low-temperature collision test environment box for vehicle body parts includes a test room, a first camera and a second camera, a refrigeration device, and an impact head device. The test room includes an impact valve and a sealing device. The refrigeration device includes a refrigeration compensation system and a refrigeration system. The impact head device includes a punch, a connecting rod, and a sealing sleeve. When the punch punches into the impact valve, two semicircular rings are clamped on the sealing sleeve. However, this patent can only realize an impact test at a single angle, and cannot realize the temperature and humidity balance monitoring of the test piece, which is far from actual needs. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings and defects mentioned in the above background technology and provide a method and a test system for high-speed impact testing of foreign objects on rail vehicle components in a low-temperature environment that can quickly achieve a preset low-temperature environment and meet multi-angle impact tests.

[0005] In order to solve the above technical problems, the technical solution proposed by the present invention is: a foreign body high-speed impact test system for rail vehicle components in a low-temperature environment, comprising: A rapid cooling environmental box, the rapid cooling environmental box comprising: a box body, one side of the box body being an openable and closable impactor entrance door, the impactor entrance door being provided with an adjustable position sliding mechanism, the left and right sides of the adjustable position sliding mechanism being connected with a stretchable portion, the adjustable position sliding mechanism being provided with a disposable low-strength sealing insulation film, the impactor entrance port being located in the disposable low-strength sealing insulation film area, the inner walls of the other sides of the box body being provided with a liquid nitrogen condenser and an environmental temperature and humidity sensor, the liquid nitrogen condenser being connected to a self-pressurized liquid nitrogen tank through an external channel, so as to realize the conduction and transportation of a cooling medium; A fixture for fixing and installing the test piece is provided on the inner wall of the box, which is used to install the test piece; a high-speed camera is installed on the inner wall of the box; a temperature and humidity sensor of the test piece is embedded inside the test piece during the experiment; the box is connected to a strain acquisition system, which is used to collect the strain response of the impact area; A rotating support seat is arranged at the bottom of the box body and is used to adjust the rotation angle of the box body; The high-pressure air cannon system is used to provide a power source for the impact object, including an air cannon, an air compressor connected to the air cannon, a bomb bay arranged on the air cannon, and a gun barrel connected to the bomb bay. A velocimeter is provided at one end of the gun barrel outlet; when in use, the gun barrel outlet is aligned with the impact object entrance port.

[0006] In one embodiment, a gun barrel liquid nitrogen condenser is spirally wound around the outer surface of the gun barrel, and the gun barrel liquid nitrogen condenser is connected to a self-pressurized liquid nitrogen tank; a pipeline temperature and humidity sensor is installed on the outer surface of the gun barrel, and the pipeline temperature and humidity sensor is not directly in contact with the gun barrel liquid nitrogen condenser, and a disposable low-strength sealing and thermal insulation film is pasted on the outlet end of the gun barrel.

[0007] In one embodiment, the rotating support seat includes a fixed end, a rotating end and a center pin, the fixed end is hinged to the rotating end through the center pin, the fixed end is fixed to the ground by bolts, the rotational freedom of the rotating end is 0° to 75°, and the rotating end is supported by a universal wheel; A bolt fastening device is arranged on the center pin shaft, and the bolt fastening device is used for locking the rotating end; an angle scale is arranged on the center pin shaft.

[0008] In one embodiment, the moving distance of the impactor entrance of the adjustable position sliding mechanism is: L= , wherein H is the vertical distance from the impact point of the test piece to the plane of the impact object entrance port, θ is the incident angle, the disposable low-strength sealing and thermal insulation film is made of flexible material and is bonded to the impact object entrance port by gluing, the thickness of the disposable low-strength sealing and thermal insulation film is 0.1mm-2mm, the material breaking strength of the disposable low-strength sealing and thermal insulation film is not higher than 0.1MPa, and the elongation is not more than 10%, the disposable low-strength sealing and thermal insulation film is provided with a cross center mark, the barrel outlet is aligned with the center point of the cross center mark, and the stretchable part is a corrugated origami structure made of flexible thermal insulation material.

[0009] In one embodiment, a strain gauge, an auxiliary test sensor, and a humidity regulator are provided in the box. The strain gauges are circumferentially orthogonally distributed near the impact point and are 30 mm to 100 mm away from the center point of the cross center mark. A collection harness connector is provided on the inner wall of the box. One end of the collection harness connector is connected to the ambient temperature and humidity sensor, the strain gauge, and the auxiliary test sensor, and the other end is connected to a temperature and humidity processing unit arranged outside the box. 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 difference in temperature and humidity between the ambient temperature and humidity in the box and the test piece. During the cooling process, the maximum temperature difference between the test piece and the ambient temperature in the box is less than 10°C, and the maximum humidity percentage difference is less than 10%.

[0010] In one embodiment, the high-speed camera is networked through a microcomputer system to capture the entire morphology of the damage process of the impact position to be measured during the impact process, and the maximum sampling frequency of the high-speed camera system is 50,000 frames; the strain acquisition system is connected to the acquisition harness connector on the inner wall of the box through a signal transmission line and connected to the microcomputer system, the strain acquisition system has 16 channels and a maximum sampling frequency of 500,000 Hz; the speed meter is installed in front of the barrel outlet, and the speed is determined by measuring the passing time of the impact object through the laser pulse interval, and the speed measurement accuracy is ±0.01m / s.

[0011] In one embodiment, the maximum volume of the self-pressurized liquid nitrogen tank is 200L, and two intelligent liquid nitrogen flow control valves are provided at the outlet of the self-pressurized liquid nitrogen tank, which are respectively connected to the liquid nitrogen condenser in the box and the liquid nitrogen condenser in the barrel. The two intelligent liquid nitrogen flow control valves adjust the liquid nitrogen flow in real time by receiving the temperature data of the temperature and humidity processing unit. The liquid nitrogen flow is steplessly regulated within the range of 0L / min to 10L / min, and the regulation accuracy is ±0.05L / min. When the temperature difference between the ambient temperature in the box and the temperature of the test piece is ±1°C 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 in the box.

[0012] In one embodiment, the number of temperature and humidity sensors pre-embedded in the test piece is no less than 4, and they are respectively arranged at different positions of the test piece. If the relative error of the temperature and humidity data monitored at different positions is within 2%, it is determined that the test piece has reached a stable test state.

[0013] In one embodiment, the gun barrel and the impact object are installed and matched by a detachable cartridge case, the detachable cartridge case is a petal-shaped body divided into 4 to 6 parts, the outer contour of the detachable cartridge case is matched with the internal clearance of the gun barrel, the matching tolerance is 0.1 mm to 0.3 mm, and the detachable cartridge case is a trumpet-shaped arc surface; the detachable cartridge case is made of lightweight foam material, and the mass is less than 20g. After the detachable cartridge case leaves the gun barrel, it is instantly separated under air resistance.

[0014] Based on the same inventive concept, the present invention also provides a high-speed impact test method using the above-mentioned foreign body high-speed impact test system for rail vehicle components in a low-temperature environment, comprising: Open the impactor entrance door of the rapid cooling environmental chamber, install the sample to be tested on the test piece fixing fixture and lock it, connect the signal lines of all sensors to the collection harness connector on the side wall of the environmental chamber through quick-connect plugs, and then lock the impactor entrance door; The angle of the box is adjusted by rotating the support seat, and then the stretchable part is moved to adjust the center position of the impact object entrance port to a preset position; Set the temperature and humidity parameters of the environment and start the cooling and humidity adjustment program to meet the test requirements; Place the impact object in the bomb bay and seal it, turn on the air compressor and inject compressed air into the pressure cabin until the air pressure reaches the rated value; Aim the barrel outlet at the center of the impactor entrance port of the box; launch the impactor, which is accelerated by the high-pressure gas through the barrel until it hits the test sample. During this process, the velocimeter, high-speed camera, and strain acquisition system all start working to synchronously obtain all test data of the impact process of the test sample. The velocimeter, strain acquisition system, and high-speed camera are synchronously turned on by the start signal of the solenoid valve, and the response delay is within 1ms.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention provides a method and system for high-speed impact testing of foreign bodies on rail vehicle components in a low-temperature environment. The high-speed impact test of test components at different angles in a low-temperature environment is realized through a rotatable rapid cooling environment box, which is more in line with the needs of actual engineering application scenarios; the use of a disposable low-strength sealing insulation film greatly reduces the heat / humidity exchange between the test box and the external environment, ensures the stability of the test environment, not only improves the test accuracy, but also greatly reduces the test refrigeration cost. The temperature and humidity data of the sample to be tested are coupled and monitored with the temperature and humidity data of the box environment, and the environmental state in the box is more accurately regulated to ensure that the state of the sample to be tested is real and effective. At the same time, this test system integrates the launch system with various external monitoring devices, which can realize millisecond-level triggering and acquisition, ensure the consistency of the data time dimension, and reduce data processing errors. The test system can achieve a test environment of minus 150℃, which can meet the test requirements of material components in various fields for extremely cold environments. Specifically, the support seat is installed at the bottom of the box by rotating it, and the angle of the box can be flexibly adjusted. The impactor entrance door is provided with an adjustable position sliding mechanism and a scale ruler. The adjustable position sliding mechanism is connected to the left and right sides with a stretchable part, so that the adjustable position sliding mechanism can realize horizontal movement in the impactor entrance door. The moving distance can be quickly and accurately adjusted through the incident angle value and the vertical distance of the impact of the test piece to ensure the accuracy of the offset angle impact. The adjustable position sliding mechanism is provided with a disposable low-strength sealing insulation film, which not only realizes the sealing and insulation of the environmental chamber, but also minimizes the energy loss of the impact foreign body and the secondary damage of the fragments to the test piece; the disposable low-strength sealing insulation film is provided with a cross center mark, which is convenient for aiming and checking the impactor, the impactor entrance port and the entrance point before the test; the impactor entrance port is located in the disposable low-strength sealing insulation film area. Since the adjustable position sliding mechanism can realize displacement adjustment in the impactor entrance door, the position of the impactor entrance port can be adjusted. The disposable low-strength sealing insulation film is replaced after an experiment, which can ensure the rapid cooling of the inside of the environmental chamber and realize the precise control of the low-temperature environment temperature. The temperature and humidity processing unit is used to control the ambient temperature and humidity in the monitoring box and the temperature and humidity of the test piece, ensuring that the actual temperature of the test piece is consistent with the ambient temperature, thereby improving the accuracy of the test. In addition, the inner wall of the low-temperature rapid cooling environment box (except for the impactor entrance door) is paved with liquid nitrogen condenser tubes and ambient temperature and humidity sensors. The liquid nitrogen condenser tube is connected to the self-pressurized liquid nitrogen tank through the external channel of the low-temperature rapid cooling environment box, which can efficiently and conveniently achieve a low-temperature environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a schematic structural diagram of a foreign body high-speed impact test system for rail vehicle components in a low-temperature environment according to an embodiment; Figure 2 It is a schematic structural diagram of a low temperature environment cooling box according to one embodiment.

[0018] Figure 3 It is a schematic diagram of the structure of a low-temperature environment cooling box in another state according to an embodiment.

[0019] Figure 4 It is a schematic diagram of the structure of a test piece in one implementation manner.

[0020] Figure numerals: 100: rapid cooling environment box; 200: self-pressurized liquid nitrogen tank; 300: high-pressure air cannon system; 400: velocimeter; 500: strain acquisition system; 600: high-speed camera; 700: microcomputer system; 1: rotating support seat, 11: rotating end, 12: fixed end, 13: universal wheel, 14: bolt fastening device, 15: angle scale; 2: high-speed camera; 3: box body, 31: wall, 32: frame, 33: acquisition harness connector; 4: high-speed camera observation hole, 41: protective glass cover; 5: lighting equipment; 6: liquid nitrogen condenser, 61: liquid nitrogen condenser main connector (external channel); 7: impactor entrance door, 71 : Adjustable position sliding mechanism, 711: stretchable part; 72: ambient temperature and humidity sensor; 73: inclined high-speed camera mounting hole; 74: disposable low-strength sealing insulation film; 8: fixed mounting fixture for the test piece; 9: test piece; 91: temperature and humidity sensor for the test piece, 92: acquisition harness; 10: humidity regulator; 102: temperature and humidity processing unit, 103: refrigerant transmission channel, 104: intelligent liquid nitrogen flow control valve, 105: data transmission line; 310: air cannon; 301: air compressor; 302: bomb bay; 303: gun barrel; 303-1: gun barrel liquid nitrogen condenser; 303-2: insulation layer, 304: gun barrel fixing bracket. DETAILED DESCRIPTION

[0021] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0022] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0023] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0024] Example: like Figure 1 to Figure 4 As shown, a foreign body high-speed impact test system for rail vehicle components in a low-temperature environment in one embodiment includes: a rapid cooling environment box 100, a self-pressurized liquid nitrogen tank 200, a high-pressure air cannon system 300, a velocimeter 400, a strain acquisition system 500, a high-speed camera 600 and a microcomputer system 700.

[0025] Specifically, the rapid cooling environment box 100 includes: a rotating support seat 1 and a box body 3. The rotating support seat 1 is arranged at the bottom of the box body 3, and is used to adjust the rotation angle of the box body 3. The box body 3 includes a skeleton 32 and an interlayer formed by a high-strength aluminum alloy layer and a thermal insulation material. Among them, one side of the box body 3 is an impactor entrance door 7, and the inner wall surface 31 of the other side of the box body 3 is provided with a liquid nitrogen condenser 6 and an ambient temperature and humidity sensor 72, and the ambient temperature and humidity sensor 72 is used to monitor the temperature and humidity in the box body 3. The liquid nitrogen condenser 6 is connected to the self-pressurized liquid nitrogen tank 200 through the liquid nitrogen condenser main joint 61 to realize the conduction and transportation of the cooling medium. The impactor entrance door 7 is movably connected to the frame of the box body 3, and the box body 3 is sealed when the impactor entrance door 7 is closed; a fixture for fixing the test piece 9 is provided in the box body 3, which is used to install the test piece 9; after the impactor entrance door 7 is opened, it is used to place the test piece 9 in the box body 3, and an adjustable position sliding mechanism 71 is provided on the impactor entrance door 7, and a ruler is provided to determine the distance that the adjustable position sliding mechanism 71 moves left and right. A high-speed camera installation interface is installed on the inner wall of the box body 3, and there can be multiple installation interfaces. A temperature and humidity sensor 91 for the test piece is embedded inside the test piece 9, which is used to monitor the temperature and humidity of the test piece 9 body. The temperature and humidity sensor 91 for the test piece is connected to the collection harness connector 33 through the collection harness 92.

[0026] A test piece fixing fixture is provided on the inner wall of the box 3 for installing the test piece 9; a high-speed camera 600 is installed on the inner wall of the box 3, and the high-speed camera 600 captures the impact damage process of the material / component and transmits the information to the microcomputer system 700; a test piece temperature and humidity sensor 91 is embedded inside the test piece 9; the box 3 is connected to a strain acquisition system 500 for acquiring the strain response of the impact area.

[0027] The high-pressure air cannon system 300 is used to provide a power source for the impact object, including an air cannon 310, an air compressor 301 connected to the air cannon 310, a bomb bay 302 arranged on the air cannon 310, and a gun barrel 303 connected to the bomb bay 302. A velocimeter 400 is provided at one end of the outlet of the gun barrel 303, and the velocimeter 400 monitors and analyzes the instantaneous impact velocity of the impact object. More specifically, the high-pressure air cannon system 300 is started by controlling the electromagnetic valve, and the air compressor 301 stores compressed air in the pressure cabin through the air pipe, and the maximum pressure that can be tolerated is 3MPa; the pressure cabin is connected to the electromagnetic valve, and the top of the bomb bay 302 is an openable sealing cover plate, which is convenient for placing the impact object; one end of the bomb bay 302 is connected to the gun barrel 303, and when the electromagnetic valve is opened, the high-pressure gas pushes the impact object to accelerate forward in the gun barrel 303 and finally flies out of the muzzle and rushes to the test piece 9 in the rapid cooling environment box 100. When in use, the gun barrel 303 is aligned with the impact object entrance port on the impact object entrance door 7. Preferably, the outer surface of the gun barrel 303 is spirally wound with a gun barrel liquid nitrogen condenser tube 303-1, and the gun barrel liquid nitrogen condenser tube 303-1 is connected to the intelligent liquid nitrogen flow control valve 104 of the self-pressurized liquid nitrogen tank 200; the intelligent liquid nitrogen flow control valve 104 is connected to the box body 3 through the refrigerant transmission channel 103. A pipeline temperature and humidity sensor is installed on the outer surface of the gun barrel 303, and the pipeline temperature and humidity sensor is not directly in contact with the gun barrel liquid nitrogen condenser tube 303-1. A disposable low-strength sealing insulation film is pasted on the outlet end of the gun barrel 303, and a heat insulation layer 303-2 is adhered to the outer side of the gun barrel liquid nitrogen condenser tube 303-1 to reduce the heat exchange between the gun barrel 303 and the external environment. Preferably, the barrel 303 and the impact object are installed and matched through a detachable cartridge case, which is in the shape of a petal divided into 4 to 6 parts, and its outer contour is matched with the internal clearance of the barrel 303, and the matching tolerance is 0.1mm to 0.3mm, and the interior is a trumpet-shaped arc surface; the detachable cartridge case is made of lightweight foam material and has a mass of no more than 20g. After the detachable cartridge case is ejected from the barrel 303, it is instantly separated under air resistance, so that high-speed impact tests of impact foreign objects of different shapes can be realized.

[0028] The microcomputer system 700 is connected to each control and acquisition component of the entire test system to complete system control and data storage and analysis. Specifically, the high-speed camera 600 is connected to the microcomputer system to form a network to capture the entire morphology of the impact position of the sample during the impact damage process. The maximum sampling frequency of the high-speed camera 600 is 50,000 frames; the strain acquisition system 500 is connected to the acquisition harness connector 33 provided on the wall of the box 3 through a signal transmission line and connected to the microcomputer system 700. The strain acquisition system 500 is preferably 16 channels with a maximum sampling frequency of 500,000 Hz; the velocimeter 400 is installed in front of the barrel outlet, and the speed is determined by measuring the passing time of the impact object through the laser pulse interval, and the speed measurement accuracy is ±0.01m / s. The startup programs of the high-pressure air cannon system 300, the velocimeter 400, the strain acquisition system 500, and the high-speed camera 600 are all associated with the control system of the microcomputer system through prefabricated programs. When the test system is started, it is synchronously opened by the solenoid valve startup signal, and the response delay is within 1ms.

[0029] The foreign body high-speed impact test system for rail vehicle components in a low-temperature environment provided by the present invention realizes high-speed impact tests on test components at different angles in a low-temperature environment through a rotatable rapid cooling environment box 100, which is more in line with the needs of actual engineering application scenarios; the use of a disposable low-strength sealing insulation film 74 greatly reduces the heat / humidity exchange between the test box and the external environment, ensuring the stability of the test environment, not only improving the test accuracy, but also greatly reducing the test refrigeration cost. The temperature and humidity data of the test sample 9 are coupled and monitored with the temperature and humidity data of the box environment, and the environmental state in the box is more accurately regulated to ensure that the state of the test sample is real and effective. At the same time, this test system integrates the launch system with various external monitoring devices, which can realize millisecond-level triggering and acquisition, ensure the consistency of the data time dimension, and reduce data processing errors. The test system can achieve a test environment of minus 150°C, which can meet the test requirements of material components in various fields for extremely cold environments. Specifically, the rotating support seat 1 is installed at the bottom of the box body 3, and the rotating support seat 1 includes a fixed end 12 and a rotating end 11. The fixed end 12 is fixed to the ground, and the fixed end 12 is hinged with 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 impact object entrance door 7, and the left and right sides of the adjustable position sliding mechanism 71 are connected with a stretchable part 711, so that the adjustable position sliding mechanism 71 can achieve displacement adjustment on the impact object entrance door 7. A disposable low-strength sealing and heat-insulating film 74 is provided on the adjustable position sliding mechanism 71, and the impact object entrance port 75 is located in the area of ​​the disposable low-strength sealing and heat-insulating film 74. Since the adjustable position sliding mechanism 71 can achieve displacement adjustment on the impact object entrance door 7, the position of the impact object entrance port 75 is adjustable. By monitoring the corresponding temperature through the environmental temperature and humidity sensor 72 on the inner wall of the box 3 and the temperature and humidity sensor 91 of the test piece in the body of the test piece 9, the temperature and humidity difference between the two can be monitored in a controllable range during the cooling process to prevent the temperature difference inside the test piece 9 from being too large due to the cooling rate being too fast, resulting in local deformation or even failure and damage, so that the true impact resistance of the test piece cannot be obtained. Therefore, the low-temperature environmental box provided by the present invention can better obtain the true results of the high-speed impact test of the test piece 9 at different incident angles by monitoring the temperature and humidity of the test piece 9 and the box 3 and controlling the temperature and humidity difference between the two.

[0030] Specifically, in one embodiment, the box body 3 is generally in the shape of a cuboid (cube), with a beam-type material as the skeleton 32 and sheet metal as the surface skin, which is made by welding / riveting process, and the main material is aluminum alloy or carbon steel and other metal materials to ensure the load-bearing and impact resistance of the box body 3 structure. Preferably, in order to meet the requirements of thermal insulation, the wall surface 31 of the box body 3 is a sandwich insulation of high-strength aluminum alloy (carbon steel) and thermal insulation material. It not only meets the structural strength requirements of the box body 3, but also can achieve the thermal insulation effect required by the test environment. A high-speed camera observation hole 4 is opened on the box body 3.

[0031] Specifically, in one embodiment, the rotating support seat 1 includes a fixed end 12 and a rotating end 11, the fixed end 12 is fixed to the ground, the fixed end 12 and the rotating end 11 are hinged, the rotational freedom of the rotating end 11 is 0° to 75°, and when in use, after determining the required incident angle of the specimen, the rotating end 11 is rotated to a predetermined angle and then locked.

[0032] The fixed end 12 of the rotating support seat 1 is hinged to the rotating end 11 through a center pin, and the rotating end 11 is supported by a universal wheel 13 to ensure its rotational freedom around the center pin. A bolt fastening device 14 is provided on the center pin of the rotating support seat 1, and the bolt fastening device 14 is used to lock the rotating end 11 to ensure that the rotating end 11 of the rotating support seat 1 cannot rotate around the center pin in the locked state. An angle scale 15 is provided on the center pin of the rotating support seat 1. The angle scale 15 can quickly and accurately determine the rotation angle. When in use, unlock the center pin bolt fastening device 14 and the universal wheel 13 of the rotating support seat, then adjust the incident angle, and finally lock the universal wheel 13 and the center pin bolt fastening device 14 to ensure that the incident angle is fixed until the angle impact test is completed. Preferably, the rotating support seat 1 is welded with aluminum alloy (carbon steel) beam-type profiles.

[0033] Preferably, in one embodiment, the stretchable portion 711 is a corrugated origami structure made of a flexible heat-insulating material. A disposable low-strength sealing insulation film 74 is provided on the adjustable position sliding mechanism 71, and the impactor entrance port 75 is located in the area where the disposable low-strength sealing insulation film 74 is located. Preferably, the adjustable position sliding mechanism 71 slides from the center point of the incident wall surface to the edge of the stretchable portion 711, thereby ensuring the position requirement of the impactor entrance port when incident at an angle. In order to adapt to the impact position requirements under different incident angles, specifically, the moving distance of the impactor entrance port 75 is: L= , where H is the shortest vertical distance from the impact point of the test piece to the plane of the impactor entrance 75, is the angle of incidence.

[0034] Preferably, the disposable low-strength sealing insulation film 74 is made of flexible material and is bonded to the impactor entrance port 75 by gluing. The thickness of the disposable low-strength sealing insulation film 74 is 0.1 mm to 2 mm, the film material breaking strength is not higher than 0.1 MPa, and the elongation is not more than 10%. Under the above conditions, it can ensure that the test piece 9 can smoothly penetrate the disposable low-strength sealing insulation film 74, and can also ensure the insulation requirements of the cooling environment in the box 3 and the outside world, and allow the incident impactor to quickly pass through the impactor entrance port 75 without causing speed attenuation and running posture changes. The disposable low-strength sealing insulation film 74 not only realizes the sealing and heat preservation of the environmental box, but also minimizes the energy loss of the incident impactor and the secondary damage of the fragments to the test piece 9; preferably, the disposable low-strength sealing insulation film 74 is provided with a cross center mark, which is convenient for the aiming and verification of the incident impactor, the impactor entrance port 75 and the impact point before the test, and assists the aiming and alignment of the impact point position of the test piece 9 with the impact foreign body before the incident. Preferably, an oblique high-speed camera mounting hole 73 is provided on the inner wall surface of the impact object entrance door 7 for mounting a high-speed camera 600, and a laminated tempered glass protective cover is installed at the lens position.

[0035] By using the setting of the rotating support seat 1 and the impact object entrance door 7, impact tests at multiple angles and positions can be realized. The disposable low-strength sealing insulation film 74 is replaced after one experiment. The use of this device can realize impact tests at multiple angles and positions under the same working conditions, which is more in line with actual needs. In addition, the inner wall surface 31 of the low-temperature rapid cooling environment box (except the impact object entrance door) is paved with a liquid nitrogen condenser 6 and an environmental temperature and humidity sensor 72. The liquid nitrogen condenser 6 is connected to the self-pressurized liquid nitrogen tank 200 through the liquid nitrogen condenser main joint 61, which can efficiently realize the low-temperature environment setting. The box 3 includes a skeleton 32 and an interlayer formed by a high-strength aluminum alloy layer and a thermal insulation material, which can better perform low-temperature environment insulation and withstand the impact force of the impact test. The inner wall of the box 3 is provided with a humidity regulator 10 for controlling the humidity inside the box 3. The wall 31 of the box 3 is provided with a collection harness connector 33, which is used to connect the environmental temperature and humidity sensor 72, strain gauges and auxiliary test sensors (sensors are set according to different requirements, such as acceleration sensors) in the box 3. Preferably, the strain gauges are evenly distributed in the vicinity of the impact point in an orthogonal manner, 30mm to 100mm from the center of the impact point. The collection harness connector 33 is externally connected to a temperature and humidity processing unit, which is connected to the environmental temperature and humidity sensor 72 and the temperature and humidity sensor 91 of the test piece to be tested, and is used to monitor the difference between the environmental temperature and humidity in the box 3 and the temperature and humidity of the test piece 9 to be tested. During the cooling process, since it takes a certain amount of time for the ambient temperature in the box 3 to be transmitted to the test piece 9 to be tested, the temperatures of both are detected at the same time, and the maximum temperature difference between the test piece 9 and the environment in the box 3 is controlled to be less than 10°C, and the maximum humidity percentage difference is controlled to be less than 10%, so as to prevent the environmental temperature from cooling too fast, causing local deformation or failure of the test piece, affecting the accuracy of the experiment. Preferably, when the maximum temperature difference between the test piece 9 and the environment in the box 3 is 1°C and the humidity percentage difference is 2%, it is determined that the temperature and humidity of the test piece 9 are consistent with the ambient temperature and humidity, that is, the preset temperature and humidity conditions are met. In the temperature control process, the temperature priority of the test piece 9 in the control logic is higher than the ambient temperature in the box 3 to ensure that the temperature of the test piece 9 meets the standard. Preferably, when the area of ​​the test piece 9 is large or the shape is complex, the number of the test piece temperature and humidity sensors 91 is not less than 4, which are respectively set at different positions of the test piece 9. The relative error of the monitoring data at different monitoring positions is within 2%, which can determine that the test piece 9 has reached a stable test state.

[0036] 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 box body 3 via a hinge. To facilitate the installation / removal of the sample 9 inside the box body 3, a swing arm door lock is used to facilitate opening and closing.

[0037] Specifically, in one embodiment, the inner wall surface 31 of the other side of the box body 3 is provided with a liquid nitrogen condenser 6 and an ambient temperature and humidity sensor 72, and the liquid nitrogen condenser 6 is connected to the self-pressurized liquid nitrogen tank 200 through the liquid nitrogen condenser main joint 61, so as to realize the conduction and transportation of the cooling medium. Preferably, the liquid nitrogen condenser 6 is connected to the self-pressurized liquid nitrogen tank 200 through the liquid nitrogen condenser main joint 61 and automatically adjusts the liquid nitrogen flow rate in real time with the temperature change to control the temperature in the box. Preferably, the liquid nitrogen condenser 6 is a stainless steel tube with a diameter of 3 to 6 mm, distributed in an S shape along each inner wall surface and finally converged at the liquid nitrogen condenser main joint 61 and connected to the self-pressurized liquid nitrogen tank 200. Preferably, the layout of the liquid nitrogen condenser 6 on each wall surface is optimized by heat-flow coupling analysis technology, and the maximum cooling rate can reach 20°C / min, which can greatly improve the heat exchange efficiency and rate of the liquid nitrogen condenser 6, reduce the amount of liquid nitrogen used, and reduce the test cost. Preferably, the self-pressurized liquid nitrogen tank 200 is connected to the external channel of the liquid nitrogen condenser 6 of the rapid cooling environment box 100 through a low-temperature resistant pipeline, with a maximum volume of 200L. Two intelligent liquid nitrogen flow control valves 104 are configured at the interface, which are connected to the rapid cooling environment box 100 and the liquid nitrogen condenser interface respectively. The intelligent liquid nitrogen flow control valve 104 is connected to the temperature and humidity processing unit 102 through a data transmission line 105. The liquid nitrogen flow can be steplessly regulated within 0L / min~10L / min, and the regulation accuracy can reach ±0.05L / min. The temperature change of the liquid nitrogen flow regulating box and the air gun barrel is controlled in real time by accessing the program control data of the temperature and humidity processing unit 102. The liquid nitrogen flow is automatically adjusted in real time by accessing the data of the ambient temperature and humidity sensor 72 of the box 3, so as to reduce the temperature in the box 3 and stabilize the control, and the temperature control accuracy is ±0.5℃.

[0038] Before the environment in the box 3 reaches the preset stable test temperature and humidity (cooling stage), the intelligent liquid nitrogen flow control valve 104 and the humidity regulator 10 are connected through the temperature and humidity processing unit for regulation. The maximum temperature difference between the test piece 9 and the environment in the box 3 is less than 10°C, 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, and thus better adapt to the low-temperature safety protection test of rail vehicle components. Preferably, a non-circulating cooling method is used to conduct the external liquid nitrogen into the box through a pipeline for heat exchange and then flow out. The minimum ambient temperature can reach 150°C, which can not only fully meet the extreme low temperature environment requirements of rail vehicle components, but also greatly reduce the test cost.

[0039] Specifically, in one embodiment, a dedicated lighting device is provided in the box 3, and multiple walls of the box 3, such as the incident wall, side wall, and back wall, are prefabricated with dedicated installation interfaces for high-speed cameras, and a laminated tempered glass protective cover is installed at the lens position to meet the observation requirements of the test process. The low-temperature rapid cooling environment box is provided with flexible closed wire slots to facilitate the passage of various sensor data acquisition transmission lines.

[0040] When conducting a high-speed impact test on rail vehicle components under a low-temperature environment, the box 3 is fixed on the impacted side of the high-speed impact test system through the rotating support seat 1, 3 to 5 meters away from the launch tube port, and the impacted rail vehicle component is clamped at the installation position of the test piece in the box 3; data acquisition sensors, such as strain gauges, displacement meters, etc., are arranged on the impacted component, and the acquisition line is connected to the data acquisition system through a flexible closed line slot, the impact object entrance door 7 is closed and locked, the adjustable position sliding mechanism 71 is adjusted to align the launch tube with the position of the component to be impacted, the impact angle is adjusted by rotating the support seat 1 and the universal wheel 13 is locked; a high-speed camera lens is installed on the wall of the box 3 and connected to the acquisition system, the lighting equipment in the box 3 is turned on and the acquisition frame and parameters are adjusted; the liquid nitrogen condenser 6 of the box 3 is connected to the self-pressurized liquid nitrogen tank 200 through a conveying pipe, the ambient temperature in the box is set, the liquid nitrogen flow intelligent control valve is turned on, and the liquid nitrogen flow is controlled in real time by temperature until the preset temperature is reached and the temperature is maintained basically consistent throughout the test process.

[0041] Based on the same inventive concept, the present invention also provides a high-speed impact test method using the above-mentioned foreign body high-speed impact test system for rail vehicle components in a low-temperature environment, comprising: S10, open the impactor entrance door 7 of the rapid cooling environmental chamber 100, install the test sample 9 on the test piece fixing fixture and lock it, connect the signal lines of all sensors to the collection harness connector 33 on the side wall of the environmental chamber through quick-connect plugs, and then lock the impactor entrance door 7.

[0042] S20, adjusting the angle of the box body by rotating the support seat, and then moving the stretchable portion 711 to adjust the center position of the impact object entrance port to a preset position.

[0043] Specifically, open the bolt fastening device 14 on the central pin shaft of the rotating support seat 1, adjust the rotating end angle of the rotating support seat 1 (range 0° to 75°) so that the angle mark line on the scale is aligned with the incident angle. The bolt fastening device 14 is aligned and locked, and then the impact object entrance port 75 of the impact object entrance door 7 is moved to a position of L= (Where H is the vertical distance from the impact point of the specimen to the plane of the impact object entrance 75, is the incident angle), so that the cross center mark on the disposable low-strength sealing insulation film 74 is aligned with the aiming laser of the barrel 303. The stretchable part is moved to adjust the center position of the impact object entrance port 75 to a preset position.

[0044] Specifically, the stretchable part 711 on the rapid cooling environment box 100 is moved so that the center position mark line of the impactor entrance port 75 is located at the scale "0". Preferably, the test sample 9 and the impactor are placed in the rapid cooling environment box 100 and cooled to the test temperature 24 hours before the test.

[0045] S30, set the temperature and humidity parameters of the environment and start the program to start cooling and adjusting the humidity to the test requirements.

[0046] Specifically, the temperature and humidity of the rapid cooling environmental box 100 are set through the temperature and humidity processing unit and the program is started to start cooling and humidity adjustment. The temperature and humidity of the environment and the sample are displayed in real time through the display module. Before the preset stable test temperature and humidity are reached (cooling stage), the processing unit program will control the maximum temperature difference between the sample and the environment in the box to be less than or equal to 10°C, and the maximum humidity percentage difference to be less than or equal to 10%; when the temperature in the rapid cooling environmental box 100 reaches the preset temperature value (error ±1°C), the humidity reaches the preset humidity value (error 1%), and the temperature error between the sample and the environment box is ±1°C, and the humidity error is 2%, it is determined that the sample temperature and humidity are consistent with the ambient temperature and humidity, meeting the test requirements.

[0047] S40, placing the impact object in the bomb cabin 302 and sealing it, turning on the air compressor 301 to inject compressed air into the pressure cabin until the air pressure reaches the rated value.

[0048] Specifically, the impact object is placed in the detachable cartridge case, and then the detachable cartridge case is placed in the cartridge case 302 and the cover is locked and sealed, and the air compressor 301 is turned on to inject compressed air into the pressure chamber until the air pressure reaches the rated value.

[0049] S50, align the gun barrel outlet with the center position of the impactor entrance port of the box body 3; launch the impactor, which is accelerated by the high-pressure gas through the gun barrel 303 until it hits the test sample. During this process, the velocimeter 400, the high-speed camera 600, and the strain acquisition system 500 all start working to synchronously obtain all test data of the impact process of the test sample.

[0050] Specifically, the electromagnetic valve is started, and the impact object is accelerated through the barrel 303 under the push of high-pressure gas until it hits the sample. During this process, the velocimeter 400, the high-speed camera 600, the strain acquisition system 500 and the auxiliary detection system are all stimulated by the electromagnetic valve start signal to start working, and all test data of the sample impact process are synchronously obtained. During this process, the velocimeter, the high-speed camera, and the strain acquisition system all start working, and all test data of the impact process of the sample to be tested are synchronously obtained. The velocimeter, the strain acquisition system and the high-speed camera are synchronously opened by the electromagnetic valve start signal, and the response delay is within 1ms.

[0051] Preferably, after the high-speed impact test of the test sample 9 is completed, the impact object entrance door 7 is opened to take out the test sample 9, and the disposable low-strength sealing and heat-insulating film is replaced before waiting for the next impact test.

Claims

1. A foreign body high-speed impact test system for rail vehicle components in a low-temperature environment, characterized in that: include: A rapid cooling environmental box, the rapid cooling environmental box comprising: a box body, one side of the box body being an openable and closable impactor entrance door, the impactor entrance door being provided with an adjustable position sliding mechanism, the left and right sides of the adjustable position sliding mechanism being connected with a stretchable portion, the adjustable position sliding mechanism being provided with a disposable low-strength sealing insulation film, the impactor entrance port being located in the disposable low-strength sealing insulation film area, the inner walls of the other sides of the box body being provided with a liquid nitrogen condenser and an environmental temperature and humidity sensor, the liquid nitrogen condenser being connected to a self-pressurized liquid nitrogen tank through an external channel, so as to realize the conduction and transportation of a cooling medium; A fixture for fixing and installing the test piece is provided on the inner wall of the box, which is used to install the test piece; a high-speed camera is installed on the inner wall of the box; a temperature and humidity sensor of the test piece is embedded inside the test piece during the experiment; the box is connected to a strain acquisition system, which is used to collect the strain response of the impact area; A rotating support seat is arranged at the bottom of the box body and is used to adjust the rotation angle of the box body; The high-pressure air cannon system is used to provide a power source for the impact object, including an air cannon, an air compressor connected to the air cannon, a bomb bay arranged on the air cannon, and a gun barrel connected to the bomb bay. A velocimeter is provided at one end of the gun barrel outlet; when in use, the gun barrel outlet is aligned with the impact object entrance port.

2. The foreign body high-speed impact test system for rail vehicle components in a low-temperature environment according to claim 1 is characterized in that: The outer surface of the gun barrel is spirally wound with a gun barrel liquid nitrogen condenser, and the gun barrel liquid nitrogen condenser is connected to a self-pressurized liquid nitrogen tank; a pipeline temperature and humidity sensor is installed on the outer surface of the gun barrel, and the pipeline temperature and humidity sensor is not directly in contact with the gun barrel liquid nitrogen condenser, and a disposable low-strength sealing and insulation film is pasted on the outlet end of the gun barrel.

3. The foreign body high-speed impact test system for rail vehicle components in a low-temperature environment according to claim 1 is characterized in that: The rotating support seat includes a fixed end, a rotating end and a center pin shaft. The fixed end is hinged to the rotating end through the center pin shaft. The fixed end is fixed to the ground through bolts. The rotational freedom of the rotating end is 0° to 75°. The rotating end is supported by a universal wheel. A bolt fastening device is arranged on the center pin shaft, and the bolt fastening device is used for locking the rotating end; an angle scale is arranged on the center pin shaft.

4. The foreign body high-speed impact test system for rail vehicle components in a low-temperature environment according to claim 1 is characterized in that: The moving distance of the impact object entrance port of the adjustable position sliding mechanism is: L= , where H is the vertical distance from the impact point of the test piece to the plane of the impactor entrance, is the incident angle, the disposable low-strength sealing and insulation film is made of flexible material and is adhered to the incident port of the impactor by gluing, the thickness of the disposable low-strength sealing and insulation film is 0.1mm~2mm, the material destructive strength of the disposable low-strength sealing and insulation film is not higher than 0.1MPa, and the elongation is not more than 10%. The disposable low-strength sealing and insulation film is provided with a cross center mark, the barrel outlet is aligned with the center point of the cross center mark, and the stretchable part is a corrugated origami structure made of flexible insulation material.

5. The foreign body high-speed impact test system for rail vehicle components in a low-temperature environment according to claim 4 is characterized in that: The box is equipped with strain gauges, auxiliary test sensors, and humidity regulators. The strain gauges are circumferentially orthogonally distributed near the impact point, and are 30mm to 100mm away from the center point of the cross center mark. The inner wall of the box is provided with a collection harness connector, one end of which is connected to the ambient temperature and humidity sensor, the strain gauge and the auxiliary test sensor, and the other end is connected to the temperature and humidity processing unit arranged outside the box. 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 difference in temperature and humidity between the ambient temperature and humidity in the box and the test piece. During the cooling process, the maximum temperature difference between the test piece and the ambient environment in the box is less than 10°C, and the maximum humidity percentage difference is less than 10%.

6. The foreign body high-speed impact test system for rail vehicle components in a low-temperature environment according to claim 1 is characterized in that: The high-speed camera is networked through a microcomputer system to capture the entire morphology of the damage process of the impact position to be measured during the impact process. The maximum sampling frequency of the high-speed camera system is 50,000 frames. The strain acquisition system is connected to the acquisition harness connector on the inner wall of the box through a signal transmission line and connected to the microcomputer system. The strain acquisition system has 16 channels and a maximum sampling frequency of 500,000 Hz. The speed meter is installed in front of the barrel outlet, and the speed is determined by measuring the passing time of the impact object through the laser pulse interval, and the speed measurement accuracy is ±0.01 m / s.

7. The foreign body high-speed impact test system for rail vehicle components in a low-temperature environment according to claim 1 is characterized in that: The maximum volume of the self-pressurized liquid nitrogen tank is 200L. Two intelligent liquid nitrogen flow control valves are installed at the outlet of the self-pressurized liquid nitrogen tank, which are respectively connected to the liquid nitrogen condenser in the box and the liquid nitrogen condenser in the barrel. The two intelligent liquid nitrogen flow control valves adjust the liquid nitrogen flow in real time by receiving the temperature data of the temperature and humidity processing unit. The liquid nitrogen flow is steplessly regulated within the range of 0L / min to 10L / min, with a regulation accuracy of ±0.05L / min. When the temperature difference between the ambient temperature in the box and the temperature of the test piece is ±1°C and the humidity difference is 2%, it is judged that the temperature and humidity of the sample are consistent with the ambient temperature and humidity in the box.

8. The foreign body high-speed impact test system for rail vehicle components in a low-temperature environment according to claim 1 is characterized in that: The number of temperature and humidity sensors embedded in the test piece is no less than 4, and they are respectively set at different positions of the test piece. If the relative error of the temperature and humidity data monitored at different positions is within 2%, it is determined that the test piece has reached a stable test state.

9. The foreign body high-speed impact test system for rail vehicle components in a low-temperature environment according to claim 1, characterized in that: The gun barrel and the impact object are installed and matched through a detachable cartridge case. The detachable cartridge case is a petal-shaped body divided into 4 to 6 parts. The outer contour of the detachable cartridge case matches the internal clearance of the gun barrel. The matching tolerance is 0.1mm to 0.3mm. The detachable cartridge case is a trumpet-shaped arc surface. The detachable cartridge case is made of lightweight foam material with a mass of less than 20g. After leaving the gun barrel, the detachable cartridge case is instantly separated under air resistance.

10. A high-speed impact test method using the foreign body high-speed impact test system for rail vehicle components in a low-temperature environment according to any one of claims 1 to 9, comprising: Open the impactor entrance door of the rapid cooling environmental chamber, install the sample to be tested on the test piece fixing fixture and lock it, connect the signal lines of all sensors to the collection harness connector on the side wall of the environmental chamber through quick-connect plugs, and then lock the impactor entrance door; The angle of the box is adjusted by rotating the support seat, and then the stretchable part is moved to adjust the center position of the impact object entrance port to a preset position; Set the temperature and humidity parameters of the environment and start the cooling and humidity adjustment program to meet the test requirements; Place the impact object in the bomb bay and seal it, turn on the air compressor and inject compressed air into the pressure cabin until the air pressure reaches the rated value; Aim the barrel outlet at the center of the impactor entrance port of the box; launch the impactor, which is accelerated by the high-pressure gas through the barrel until it hits the test sample. During this process, the velocimeter, high-speed camera, and strain acquisition system all start working to synchronously obtain all test data of the impact process of the test sample. The velocimeter, strain acquisition system, and high-speed camera are synchronously turned on by the start signal of the solenoid valve, and the response delay is within 1ms.

Images