Method and system for high-speed impact test of foreign matter on rail vehicle components in low-temperature environment

Abstract

The present application belongs to the field of high-speed impact experiment of track vehicle components, and discloses a kind of low-temperature environment track vehicle component foreign matter high-speed impact test method and system, comprising: fast cooling environment box, including: bottom rotatable box, one side of box is the impact object incident door that can be opened and closed, adjustable position sliding mechanism is equipped on impact object incident door, the left and right sides of adjustable position sliding mechanism are connected with stretchable part, disposable low-strength sealing heat insulation film is equipped on adjustable position sliding mechanism, liquid nitrogen condenser pipe and environmental temperature and humidity sensor are laid on the inner wall of other side of box;Box inner wall is equipped with the test piece fixed mounting fixture;Box inner wall is equipped with high-speed camera;When carrying out experiment, test piece temperature and humidity sensor is embedded in the inside of test piece;Box is connected with strain acquisition system;It further includes high-pressure air cannon system.The above-mentioned environment box can quickly realize preset low-temperature environment and can carry out multi-angle impact test.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of high-speed impact experiment of foreign matters on rail vehicle parts, and particularly relates to a high-speed impact test method and test system of foreign matters on rail vehicle parts under low-temperature environment. BACKGROUND

[0002] With the rapid development of rail vehicle technology in China, various train equipment is facing the risk of impact by impact objects such as falling rocks, hail and ballast, which seriously affects the safety of train operation. Therefore, various parts / materials of rail vehicles need to carry out different levels of high-speed impact test of foreign matters to ensure the impact resistance of the car body structure parts. The high-speed impact test of foreign matters on rail vehicle structure parts is generally carried out in a laboratory environment (normal temperature), while China has a vast territory, and various extreme cold weather occurs frequently. The ductile-brittle transition of the car body material occurs under low-temperature conditions, which greatly reduces the anti-foreign matter impact ability of the structure parts, especially the trains exported to northern Europe and other high-latitude countries. Therefore, carrying out high-speed impact test of foreign matters on rail vehicle structure parts under low-temperature conditions is an important content to ensure the safe operation of trains in extreme low-temperature environment.

[0003] Chinese patent application with publication number CN111157370A discloses a car body part low-temperature impact test environment box and a test method thereof. The car body part low-temperature impact test environment box includes a test room, first and second cameras, 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 penetrates into the impact valve, two semicircular rings are clamped on the sealing sleeve. However, this patent can only realize a single angle impact test, and cannot realize the temperature and humidity balance monitoring of the test piece, which is far from the actual demand. SUMMARY

[0004] The technical problem to be solved by the present application is to overcome the deficiencies and defects mentioned in the above background technology, and to provide a high-speed impact test method and test system of foreign matters on rail vehicle parts under low-temperature environment, which can quickly realize the preset low-temperature environment and meet the multi-angle impact test.

[0005] To solve the above technical problems, the technical solution provided by the present application is as follows: a high-speed impact test system of foreign matters on rail vehicle parts under low-temperature environment, comprising:

[0006] A rapid cooling environment chamber includes: a chamber body, one side of which is an openable and closable impactor inlet door, an adjustable position sliding mechanism, and stretchable parts connected to the left and right sides of the adjustable position sliding mechanism. The adjustable position sliding mechanism is equipped with a disposable low-strength sealing and heat insulation film, and the impactor inlet is located in the area of ​​the disposable low-strength sealing and heat insulation film. The inner walls of the other sides of the chamber body are covered 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 through an external channel to realize the conduction and transportation of the cooling medium.

[0007] The inner wall of the chamber is equipped with a fixture for fixing the test piece to be installed; a high-speed camera is installed on the inner wall of the chamber; a temperature and humidity sensor for the test piece is pre-embedded inside the test piece during the experiment; the chamber is connected to a strain acquisition system for acquiring the strain response of the impact area.

[0008] A rotating support base is located at the bottom of the box and is used to adjust the rotation angle of the box.

[0009] A high-pressure air cannon system is used to provide a power source for an impactor. It includes an air cannon, an air compressor connected to the air cannon, a magazine mounted on the air cannon, and a cannon barrel connected to the magazine. A velocity measuring instrument is provided at one end of the cannon barrel outlet. When in use, the cannon barrel outlet is aligned with the impactor's inlet.

[0010] In one embodiment, a liquid nitrogen condenser tube is spirally wound around the outer surface of the gun barrel, and the liquid nitrogen condenser tube is connected to a self-pressurized liquid nitrogen tank; a pipe temperature and humidity sensor is installed on the outer surface of the gun barrel, and the pipe temperature and humidity sensor does not directly contact the liquid nitrogen condenser tube; a disposable low-strength sealing and heat insulation film is pasted on the outlet end of the gun barrel.

[0011] In one embodiment, the rotating support includes a fixed end, a rotating end, and a central pin. The fixed end is hinged to the rotating end via the central pin and is fixed to the ground by bolts. The rotating end has a rotational degree of freedom of 0° to 75° and is supported by casters.

[0012] 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.

[0013] In one embodiment, the distance the adjustable position sliding mechanism moves at the impactor inlet is: L = Wherein H is the vertical distance from the impact point position of the test piece to the impact object incident plane, and θ is the incident angle, the one-time low-strength sealing thermal insulation film is made of flexible material and is pasted on the impact object incident port by adhesive, the thickness of the one-time low-strength sealing thermal insulation film is 0.1mm-2mm, the material breaking strength of the one-time low-strength sealing thermal insulation film is not higher than 0.1MPa, and the elongation rate is not more than 10%, the one-time low-strength sealing thermal insulation film is provided with a cross center mark, the center point of the cross center mark is aligned with the barrel outlet, and the stretchable part is a corrugated paper structure made of flexible thermal insulation material.

[0014] In an embodiment, the box is provided with strain gauges, auxiliary test sensors and humidity regulators, the strain gauges are uniformly distributed around the impact point position and are orthogonal to the center point of the cross center mark at a distance of 30mm-100mm; the inner wall of the box is provided with a collection wire harness connector, one end of the collection wire harness connector is connected with the environmental temperature and humidity sensor, the strain gauges and the auxiliary test sensors, and the other end is connected with a temperature and humidity processing unit arranged outside the box, the temperature and humidity processing unit is connected with the environmental temperature and humidity sensor and the test piece temperature and humidity sensor, and is used for monitoring the temperature and humidity difference between the box environment and the test piece, so that the maximum temperature difference between the test piece and the box environment is less than 10℃ and the maximum humidity percentage difference is less than 10% during the cooling process.

[0015] In an embodiment, the high-speed camera is connected with a microcomputer system through networking, captures the whole morphology of the damage process of the test impact position during the impact process, and the maximum sampling frequency of the high-speed camera system is 50000 frames / s; the strain collection system is connected with the microcomputer system through signal transmission lines and the collection wire harness connector on the inner wall of the box, the strain collection system has 16 channels, and the maximum sampling frequency is 500000Hz; the speedometer is installed in front of the barrel outlet and determines the speed of the impact object by measuring the time interval of laser pulses, and the speed measurement accuracy is ±0.01m / s.

[0016] In an embodiment, the maximum volume of the self-pressurized liquid nitrogen tank is 200L, two intelligent liquid nitrogen flow control valves are arranged at the outlet of the self-pressurized liquid nitrogen tank and are connected with the liquid nitrogen condensing pipe in the box and the liquid nitrogen condensing pipe of the barrel respectively, 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 controlled within 0L / min-10L / min, the control accuracy is ±0.05L / min, and when the temperature difference between the box environment and 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 temperature and humidity of the box environment.

[0017] In an embodiment, the number of the embedded temperature and humidity sensors of the test piece is not less than 4, and the temperature and humidity sensors are arranged at different positions of the test piece respectively, and the relative error of the temperature and humidity data monitored at the different positions is within 2%, so that it is determined that the test piece has reached a stable test state.

[0018] In an embodiment, the barrel and the impactor are installed and matched through a separable bullet holder, the separable bullet holder is in the shape of 4-6 petal, the outer contour of the separable bullet holder is matched with the internal gap of the barrel, the matching tolerance is 0.1-0.3 mm, and the separable bullet holder is a horn-shaped camber surface; the separable bullet holder is made of a light foaming material and has a mass less than 20 g, and the separable bullet holder is separated instantaneously under the air resistance after being discharged from the barrel.

[0019] Based on the same inventive concept, the application further provides a high-speed impact test method using the high-speed impact test system for foreign matter under low-temperature environment of a rail vehicle component, comprising:

[0020] The impactor incident door of the rapid cooling environment box is opened, the test sample is installed on the test piece fixing clamp and locked, the signal lines of all sensors are connected to the collection line bundle connector of the sidewall of the environment box through the quick connector, and then the impactor incident door is locked;

[0021] The angle of the box body is adjusted through the rotating support base, and then the center position of the impactor incident port is adjusted to the preset position through the stretchable part;

[0022] The temperature and humidity parameters of the environment are set, and the temperature and humidity program is started to the test requirement;

[0023] The impactor is placed in the bullet cabin and sealed, the air compressor is started to inject compressed air into the pressure cabin until the air pressure reaches the rated value;

[0024] The barrel outlet is aligned with the center position of the impactor incident port of the box body; the impactor is launched, the impactor is accelerated through the barrel under the push of the high-pressure gas until it hits the test sample, in this process, the speedometer, the high-speed camera and the strain acquisition system all start to work, and all the test data of the impact process of the test sample are synchronously acquired, the speedometer, the strain acquisition system and the high-speed camera are synchronously opened under the excitation of the electromagnetic valve starting signal, and the response delay is within 1 ms.

[0025] Compared with the prior art, the beneficial effects of the application are: the low-temperature environment track vehicle component foreign matter high-speed impact test method and system provided by the application realizes high-speed impact test of test components at different angles in a low-temperature environment through a rotatable rapid cooling environment box, which is more in line with the needs of engineering practical application scenarios; one-time low-strength sealing and heat insulation film is used, which greatly reduces the heat / humidity exchange between the test box and the external environment, ensures the stability of the test environment, improves the test precision, and greatly reduces the test refrigeration cost. The temperature and humidity data of the test sample and the temperature and humidity data of the box environment are coupled and monitored, the environmental state in the box is more accurately controlled, and the state of the test sample is ensured to be real and effective. At the same time, the test system integrates the launch system and various external monitoring devices, can realize millisecond-level triggering and acquisition, ensures the consistency of the time dimension of data, and reduces the data processing error. The test system can realize a test environment of minus 150 DEG C, and can meet the test needs of materials and components in extreme cold environments in various fields. Specifically, the rotatable support seat is installed at the bottom of the box, and the angle of the box can be flexibly adjusted. The adjustable position sliding mechanism and the scale ruler are arranged on the impact object incident door, the adjustable position sliding mechanism is connected with the stretchable part on the left and right sides, so that the adjustable position sliding mechanism can realize horizontal movement on the impact object incident door, the moving distance can be quickly and accurately adjusted through the incident angle value and the vertical distance of the test sample impact, and the angle impact accuracy is ensured. The one-time low-strength sealing and heat insulation film is arranged on the adjustable position sliding mechanism, which not only realizes the sealing and heat preservation of the environment box, but also maximally reduces the energy loss of the impact foreign matter and the secondary damage of the test sample caused by the fragments; the one-time low-strength sealing and heat insulation film is provided with a cross center mark, which facilitates the aiming and checking of the impact object, the impact object incident port and the incident point before the test; the impact object incident port is located in the region of the one-time low-strength sealing and heat insulation film, and since the adjustable position sliding mechanism can realize displacement adjustment on the impact object incident door, the position of the impact object incident port is adjustable. The one-time low-strength sealing and heat insulation film is replaced after one experiment, which can ensure the rapid cooling of the environment box and realize the accurate control of the low-temperature environment. The temperature and humidity of the test sample and the environment in the monitoring box are regulated and monitored by the temperature and humidity processing unit, so that the actual temperature of the test sample is consistent with the environmental temperature, and the test accuracy is improved. In addition, the inner side wall of the low-temperature rapid cooling environment box (except the impact object incident door) is paved with liquid nitrogen condensation pipes and environmental temperature and humidity sensors, the liquid nitrogen condensation pipes are connected with the self-pressurized liquid nitrogen tank through the low-temperature rapid cooling environment box external channel, and the low-temperature environment can be efficiently and conveniently realized. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0027] Fig. 1 Fig. 1 is a structural schematic diagram of a high-speed impact test system for a rail vehicle component in a low-temperature environment according to an embodiment;

[0028] Fig. 2 Fig. 2 is a structural schematic diagram of a low-temperature environment cooling box according to an embodiment.

[0029] Fig. 3 Fig. 3 is another state structural schematic diagram of a low-temperature environment cooling box according to an embodiment.

[0030] Fig. 4 Fig. 4 is a structural schematic diagram of a test piece according to an embodiment.

[0031] Fig. 1 is a structural schematic diagram of a high-speed impact test system for a rail vehicle component in a low-temperature environment according to an embodiment; Fig. 2 is a structural schematic diagram of a low-temperature environment cooling box according to an embodiment; Fig. 3 is another state structural schematic diagram of a low-temperature environment cooling box according to an embodiment; Fig. 4 is a structural schematic diagram of a test piece according to an embodiment; Fig. 5 is a structural schematic diagram of a high-speed impact test system for a rail vehicle component in a low-temperature environment according to an embodiment; and Fig. 6 is a structural schematic diagram of a high-speed impact test system for a rail vehicle component in a low-temperature environment according to an embodiment. The specific embodiments of the present application will be described below with reference to the accompanying drawings. It is obvious that the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings. DETAILED DESCRIPTION

[0032] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings and preferred embodiments. However, the scope of protection of the present application is not limited to the following specific embodiments.

[0033] 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.

[0034] 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.

[0035] Example:

[0036] like Figs. 1-4 As shown, a high-speed impact test system for foreign objects on rail vehicle components under low-temperature conditions according to one embodiment includes: a rapid cooling environment chamber 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.

[0037] Specifically, the rapid cooling environment chamber 100 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 is used to adjust the rotation angle of the chamber body 3. The chamber body 3 includes a frame 32 and a sandwich layer formed by a high-strength aluminum alloy layer and insulation material. One side of the chamber body 3 is an impactor entry door 7, and the inner wall surface 31 of the other sides of the chamber body 3 is covered with liquid nitrogen condensation pipes 6 and environmental temperature and humidity sensors 72, which are used to monitor the temperature and humidity inside the chamber body 3. The liquid nitrogen condensation pipes 6 are connected to the self-pressurized liquid nitrogen tank 200 through a liquid nitrogen condensation pipe main connector 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.

[0038] The inner wall of the chamber 3 is equipped with a fixture for fixing the test piece 9, which is used to install the test piece 9; a high-speed camera 600 is installed on the inner wall of the chamber 3, which captures the impact failure process of the material / component and transmits the information to the microcomputer system 700; a temperature and humidity sensor 91 is embedded inside the test piece 9; the chamber 3 is connected to a strain acquisition system 500, which is used to collect the strain response of the impact area.

[0039] The high-pressure air cannon system 300 for providing a power source for the impact object includes an air cannon 310, an air compressor 301 connected with the air cannon 310, a projectile cabin 302 arranged on the air cannon 310, and a cannon barrel 303 connected with the projectile cabin 302, wherein the cannon barrel 303 is provided with a velocity meter 400 at an outlet end thereof, and the velocity meter 400 monitors and analyzes the instantaneous impact speed of the impact object. More specifically, the high-pressure air cannon system 300 is started by electromagnetic valve control, the air compressor 301 stores compressed air in the pressure cabin through the air pipe, and the maximum bearing pressure is 3 MPa; the pressure cabin is connected with an electromagnetic valve, the top of the projectile cabin 302 is a sealable cover plate, which is convenient for placing the impact object; one end of the projectile cabin 302 is connected with the cannon barrel 303, when the electromagnetic valve is opened, the high-pressure gas pushes the impact object to accelerate in the cannon barrel 303 and finally flies out of the muzzle and hits the test piece 9 in the rapid cooling environment box 100. In use, the cannon barrel 303 is aligned with the impact object incident port on the impact object incident door 7. Preferably, the outer surface of the cannon barrel 303 is spirally wound with a cannon barrel liquid nitrogen condensing pipe 303-1, the cannon barrel liquid nitrogen condensing pipe 303-1 is connected with the intelligent liquid nitrogen flow control valve 104 of the self-pressurizing liquid nitrogen tank 200, and the intelligent liquid nitrogen flow control valve 104 is connected with the box body 3 through the refrigerant transmission channel 103. The pipeline temperature and humidity sensor is installed on the outer surface of the cannon barrel 303, and the pipeline temperature and humidity sensor does not directly contact the cannon barrel liquid nitrogen condensing pipe 303-1, a one-time low-strength sealing and heat insulation film is pasted at the outlet end of the cannon barrel 303, and a heat insulation layer 303-2 is adhered outside the cannon barrel liquid nitrogen condensing pipe 303-1, so as to reduce the heat exchange between the cannon barrel 303 and the external environment. Preferably, the cannon barrel 303 and the impact object are installed and matched through a separable projectile support, the separable projectile support is 4-6 petal-shaped, the outer contour thereof is matched with the internal gap of the cannon barrel 303, the matching tolerance is 0.1-0.3 mm, and the inside is a horn-shaped arc surface; the separable projectile support is made of light foaming material and has a mass of not more than 20 g, the separable projectile support is separated instantaneously under air resistance after being shot out of the cannon barrel 303, and high-speed impact tests of impact objects with different shapes can be realized.

[0040] The microcomputer system 700 is connected with various control and acquisition components of the whole test system, and completes system control and data storage analysis. Specifically, the high-speed camera 600 is connected with the microcomputer system to form a network, captures the whole morphology of the impact position of the test sample in the impact damage process, and the maximum sampling frequency of the high-speed camera 600 is 50000 frames / s; the strain acquisition system 500 is connected with the microcomputer system 700 through signal transmission lines and connected with the acquisition line bundle joint 33 arranged on the wall surface of the box 3, the strain acquisition system 500 is preferably 16 channels, and the maximum sampling frequency is 500000 Hz; the speedometer 400 is installed in front of the outlet of the barrel, the speed of the impact object is determined by measuring the passing time through the laser pulse interval, and the speed measurement accuracy is ±0.01 m / s. The starting programs of the high-pressure air gun system 300, the speedometer 400, the strain acquisition system 500 and the high-speed camera 600 are all associated with the control system of the microcomputer system through the pre-prepared program, and when the test system starts, they are synchronously opened under the excitation of the electromagnetic valve starting signal, and the response delay is within 1 ms.

[0041] The low-temperature environment rail vehicle component foreign matter high-speed impact test system provided by the application realizes high-speed impact test of a test component at different angles in a low-temperature environment through a rotatable rapid cooling environment box 100, and is more in line with the needs of engineering practical application scenarios; a one-time low-strength sealing and heat insulation film 74 is used, which greatly reduces the heat / humidity exchange between the test box body and the external environment, ensures the stability of the test environment, improves the test precision, and greatly reduces the test refrigeration cost. The temperature and humidity data of the sample 9 to be tested and the temperature and humidity data of the box body environment are coupled and monitored, the environmental state in the box is more accurately controlled, and the state of the sample to be tested is ensured to be real and effective. At the same time, the test system integrates the launch system and various external monitoring devices, can realize millisecond-level triggering and acquisition, ensures the consistency of the time dimension of the data, and reduces the data processing error. The test system can realize a test environment of minus 150 DEG C, and can meet the test needs of materials and components in various fields in extreme cold environments. Specifically, the rotatable support seat 1 is installed at the bottom of the box body 3, the rotatable support seat 1 comprises a fixed end 12 and a rotating end 11, the fixed end 12 is fixed to the ground, the fixed end 12 is hinged to the rotating end 11, the rotating degree of freedom of the rotating end 11 is 0 DEG ~ 75 DEG, and the rotating end 11 is locked after rotating a predetermined angle. An adjustable position sliding mechanism 71 is arranged on the impact object incidence door 7, and the left and right sides of the adjustable position sliding mechanism 71 are connected with stretchable parts 711, so that the adjustable position sliding mechanism 71 can realize displacement adjustment on the impact object incidence door 7. A one-time low-strength sealing and heat insulation film 74 is arranged on the adjustable position sliding mechanism 71, and an impact object incidence port 75 is located in the region of the one-time low-strength sealing and heat insulation film 74. Since the adjustable position sliding mechanism 71 can realize displacement adjustment on the impact object incidence door 7, the position of the impact object incidence port 75 can be adjusted. The corresponding temperatures are monitored by the environmental temperature and humidity sensors 72 on the inner wall of the box body 3 and the sample temperature and humidity sensors 91 in the body of the sample 9 to be tested, so that the temperature and humidity difference of the two can be monitored in a controllable range during the cooling process, so as to prevent the internal temperature difference of the sample 9 to be tested from being too large due to too fast cooling rate, and local deformation or even failure and damage occur, so that the real impact resistance of the test piece cannot be obtained. Therefore, the low-temperature environment box provided by the application can better obtain the real results of the sample 9 to be tested in high-speed impact test at different incidence angles by monitoring and controlling the temperature and humidity of the sample 9 to be tested and the box body 3.

[0042] Specifically, in an embodiment, the box 3 is generally cuboid in shape, made of aluminum alloy or carbon steel, etc. as the main material, with a beam type material as the skeleton 32 and sheet metal as the surface skin, by welding / riveting process, to ensure the load bearing and impact resistance of the box 3 structure. Preferably, to meet the heat insulation requirement, the wall 31 of the box 3 is a sandwich heat insulation of high-strength aluminum alloy (carbon steel) and heat insulation material, which not only meets the structural strength requirement of the box 3, but also achieves the heat insulation effect required by the test environment. A high-speed camera observation hole 4 is provided on the box 3.

[0043] Specifically, in an embodiment, the rotating support base 1 includes a fixed end 12 and a rotating end 11, the fixed end 12 is fixed to the ground, the fixed end 12 is hinged to the rotating end 11, and the rotating degree of freedom of the rotating end 11 is 0°-75°. In use, after determining the required incident angle of the test piece, the rotating end 11 is rotated to the predetermined angle and locked.

[0044] The fixed end 12 of the rotating support base 1 is hinged to the rotating end 11 through a center pin shaft, and the rotating end 11 is supported by universal wheels 13 to ensure its rotation freedom around the center pin shaft. A bolt fastening device 14 is provided on the center pin shaft of the rotating support base 1, which is used to lock the rotating end 11 and ensure that the rotating end 11 of the rotating support base 1 cannot rotate around the center pin shaft in the locked state. An angle scale 15 is provided on the center pin shaft of the rotating support base 1. The angle scale 15 can quickly and accurately determine the rotation angle. In use, the center pin shaft bolt fastening device 14 and the universal wheels 13 of the rotating support base are unlocked, then the incident angle is adjusted, and finally the universal wheels 13 and the center pin shaft 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 base 1 is made of aluminum alloy (carbon steel) beam type material by welding.

[0045] Preferably, in an embodiment, the stretchable part 711 is a corrugated paper structure made of flexible heat insulation material. A one-time low-strength sealed heat insulation film 74 is provided on the adjustable position sliding mechanism 71, and an impact object incident port 75 is located in the area of the one-time low-strength sealed heat insulation film 74. Preferably, the sliding position of the adjustable position sliding mechanism 71 through the stretchable part 711 is from the center point of the incident wall to the edge of the stretchable part 711, which ensures the position requirement of the impact object incident port when the incident angle is deviated. To adapt to the impact position requirement under different incident angles, specifically, the moving distance of the impact object incident port 75 is: where H is the shortest vertical distance from the impact point position of the test piece to the plane of the impact object incident port 75, is the incident angle.

[0046] Preferably, the disposable low-strength sealing and heat insulation film 74 is made of flexible material and is attached to the impact object entrance 75 by adhesive. The thickness of the disposable low-strength sealing and heat insulation film 74 is 0.1mm-2mm, the breaking strength of the film material is not higher than 0.1MPa, and the elongation rate is not more than 10%. Under the above conditions, it can be ensured that the test piece 9 can smoothly penetrate the disposable low-strength sealing and heat insulation film 74, and the cooling environment in the box 3 can be guaranteed to be insulated from the outside environment, and the incident impact object can quickly pass through the impact object entrance 75 without causing speed attenuation and running attitude change. The disposable low-strength sealing and heat insulation film 74 not only realizes the sealing and heat preservation of the environmental box, but also maximally reduces the energy loss of the incident impact object and the secondary damage of the fragments to the test piece 9; preferably, the disposable low-strength sealing and heat insulation film 74 is provided with a cross center mark, which facilitates the aiming and checking of the incident impact object, the impact object entrance 75 and the incident point before the test, and assists the aiming alignment of the impact point position of the test piece 9 and the incident impact object before the test. Preferably, the inner wall surface of the impact object entrance 7 is provided with an obliquely arranged high-speed camera mounting hole 73 for mounting the high-speed camera 600, and a clamped and glued tempered glass protective cover is arranged at the lens position.

[0047] With the arrangement of the rotating support base 1 and the impact object incident door 7, multi-angle and multi-position impact experiments can be realized, and the one-time low-strength sealing and heat insulation film 74 is replaced after one experiment. The device can realize multi-angle and multi-position impact experiments under the same working conditions, which is more in line with actual needs. In addition, the inner side wall surface 31 (except the impact object incident door) of the low-temperature rapid cooling environment box is paved with liquid nitrogen condensing pipes 6 and environmental temperature and humidity sensors 72. The liquid nitrogen condensing pipes 6 are connected with the self-pressurized liquid nitrogen tank 200 through the liquid nitrogen condensing pipe total joint 61, and the low-temperature environment setting can be efficiently realized. The box 3 includes a framework 32 and a sandwich formed by a high-strength aluminum alloy layer and a heat preservation material, which can better preserve the low-temperature environment and bear 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 surface 31 of the box 3 is provided with a collection wire harness joint 33 for connecting the environmental temperature and humidity sensors 72, strain gauges and auxiliary test sensors (sensors such as acceleration sensors are arranged according to different requirements) inside the box 3. Preferably, the strain gauges are orthogonally and uniformly distributed around the impact point position, and are 30mm-100mm away from the center position of the impact point. The collection wire harness joint 33 is externally connected with a temperature and humidity processing unit, which is connected with the environmental temperature and humidity sensors 72 and the temperature and humidity sensors 91 of the test piece 9, for monitoring the difference between the environmental temperature and humidity inside the box 3 and the temperature and humidity of the test piece 9. During the cooling process, since it takes a certain time for the environmental temperature inside the box 3 to be conducted to the test piece 9, the temperatures of the two are detected at the same time, and the maximum temperature difference between the test piece 9 and the environment inside the box 3 is less than 10℃, and the maximum humidity percentage difference is less than 10%, so as to prevent the local deformation or failure of the test piece caused by the too fast temperature drop of the environment, which affects the accuracy of the experiment. Preferably, when the maximum temperature difference between the test piece 9 and the environment inside the box 3 is 1℃, and the humidity percentage difference is 2%, it is determined that the temperature and humidity of the test piece 9 are consistent with the environmental temperature and humidity, that is, the preset temperature and humidity conditions are reached. During the temperature control process, the priority of the temperature of the test piece 9 is higher than that of the environment inside the box 3, so as 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 temperature and humidity sensors 91 of the test piece is not less than 4, which are arranged at different positions of the test piece 9. When the relative error of the monitoring data of different monitoring positions is within 2%, it is determined that the test piece 9 has reached a stable test state.

[0048] Specifically, in an embodiment, the impact object incident door 7 is a completely openable structure, and the impact object incident door 7 is connected with the framework 32 of the box 3 through a hinge. In order to facilitate the installation / dismounting of the sample 9 inside the box 3, a swing door lock is used to facilitate opening and closing.

[0049] Specifically, in an embodiment, the inner wall surface 31 of the other side of the box 3 is paved with a liquid nitrogen condensing pipe 6 and an ambient temperature and humidity sensor 72. The liquid nitrogen condensing pipe 6 is connected to the self-pressurized liquid nitrogen tank 200 through a liquid nitrogen condensing pipe joint 61 to realize the conduction and delivery of the cooling medium. Preferably, the liquid nitrogen condensing pipe 6 is connected to the self-pressurized liquid nitrogen tank 200 through the liquid nitrogen condensing pipe joint 61 and automatically adjusts the liquid nitrogen flow in real time according to the temperature change to control the temperature in the box. Preferably, the liquid nitrogen condensing pipe 6 is a stainless steel pipe with a pipe diameter of 3-6 mm, which is distributed in an S shape along the inner wall surface and finally converges to the liquid nitrogen condensing pipe joint 61 connected to the self-pressurized liquid nitrogen tank 200. Preferably, the layout of the liquid nitrogen condensing pipe 6 on each wall surface is optimized by using a heat-flow coupling analysis technology, and the cooling rate can reach 20℃ / min, which can greatly improve the heat exchange efficiency and rate of the liquid nitrogen condensing pipe 6, reduce the use of liquid nitrogen, and reduce the test cost. Preferably, the self-pressurized liquid nitrogen tank 200 is connected to the liquid nitrogen condensing pipe 6 external access channel 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 arranged at the interface, which are connected to the rapid cooling environment box 100 and the liquid nitrogen condensing pipe 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, and the liquid nitrogen flow can be steplessly controlled within 0L / min-10L / min, with a control accuracy of ±0.05L / min. The liquid nitrogen flow is adjusted in real time by the program-controlled data of the temperature and humidity processing unit 102 to control the temperature change of the box and the air cannon barrel. The liquid nitrogen flow is automatically adjusted in real time by the data of the ambient temperature and humidity sensor 72 of the box 3 to reduce the temperature in the box 3 and stabilize the control, with a temperature control accuracy of ±0.5℃.

[0050] 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 controlled by the temperature and humidity processing unit to ensure that the maximum temperature difference between the test piece 9 and the environment in the box 3 is less than 10℃ and the maximum humidity percentage difference is less than 10%, which ensures the stability and accuracy of the experimental results. Using liquid nitrogen as the cooling medium can greatly improve the test cooling efficiency and significantly reduce the test cost, which is more suitable for low-temperature safety protection tests of rail vehicle components. Preferably, the non-circulating cooling mode is adopted to guide the liquid nitrogen from the outside to the box through the pipeline for heat exchange and then flow out, and the minimum environmental temperature can reach 150℃, which can not only fully meet the extreme low-temperature environmental requirements of rail vehicle components, but also greatly reduce the test cost.

[0051] Specifically, in an embodiment, a special lighting device is arranged in the box 3, and the incident wall surface, side wall surface and back wall surface of the box 3 are all pre-fabricated with a mounting interface special for a high-speed camera, and a clamp glass protection cover is arranged at the lens position to meet the observation requirement in the test process. The low-temperature rapid cooling environment box is provided with a flexible closed wire slot hole to facilitate the passing of data acquisition sensor data acquisition transmission lines.

[0052] Specifically, in the process of conducting a high-speed impact test of a rail vehicle component in a low-temperature environment, the box 3 is fixed to the impact side of the high-speed impact test system through the rotating support base 1, and the distance from the port of the launching tube is 3-5 m. The rail vehicle component to be impacted is clamped to the test piece mounting position in the box 3. Data acquisition sensors such as strain gauges and displacement meters are arranged on the impacted component, and the acquisition lines are connected to the data acquisition system through the flexible closed wire slot hole. The impact door 7 is closed and locked. The adjustable position sliding mechanism 71 is adjusted to align the launching tube with the position to be impacted. The impact angle is adjusted through the rotating support base 1, and the universal wheel 13 is locked. The high-speed camera lens is installed on the wall surface of the box 3 and connected to the acquisition system. The lighting device in the box 3 is turned on, and the acquisition frame and parameters are adjusted. The liquid nitrogen condenser pipe 6 of the box 3 is connected to the self-pressurized liquid nitrogen tank 200 through the conveying pipe. The temperature in the box is set. The liquid nitrogen flow intelligent control valve is opened. The liquid nitrogen flow is controlled in real time through the temperature. Until the preset temperature is reached and the temperature is maintained basically unchanged during the whole test process.

[0053] Based on the same inventive concept, the application also provides a high-speed impact test method using the above-mentioned high-speed impact test system of a rail vehicle component in a low-temperature environment. The method comprises the following steps:

[0054] S10, open the impact door 7 of the rapid cooling environment box 100, install the test sample 9 on the test piece fixing and mounting clamp, and lock and fix it. The signal lines of all sensors are connected to the acquisition wire harness connector 33 on the side wall of the environment box through the quick connector. Then, the impact door 7 is locked.

[0055] S20, adjust the angle of the box through the rotating support base, and then move the stretchable part 711 to adjust the center position of the impact object inlet to the preset position.

[0056] Specifically, the bolt fastening device 14 on the center pin shaft of the rotating support base 1 is opened, the rotating end angle of the rotating support base 1 is adjusted (the range is 0°-75°), the scale of the angle mark line on the scale is aligned with the incident angle of the box 3, and the bolt fastening device 14 is locked. Then, the position of the impact object inlet 75 of the impact door 7 is moved, and the moving distance L= (wherein H is the vertical distance from the impact point position of the test piece to the plane of the impact object inlet 75, The cross center mark on the disposable low-intensity sealing and heat insulation film 74 is aligned with the sighting laser of the barrel 303. The stretchable part is moved to adjust the center position of the impactor incident port 75 to the preset position.

[0057] Specifically, the stretchable part 711 on the rapid cooling environment box 100 is moved to position the impactor incident port 75 center position mark line at the scale mark "0" position. Preferably, the test sample 9 and the impactor are placed in the rapid cooling environment box 100 to cool to the test temperature 24 hours before the test.

[0058] S30, set the temperature and humidity parameters of the environment and start the program to start cooling and humidifying to the test requirements.

[0059] Specifically, the temperature and humidity of the rapid cooling environment box 100 are set by the temperature and humidity processing unit, and the program is started to start cooling and humidifying. The display module displays the temperature and humidity of the environment and the test sample in real time. Before the preset stable test temperature and humidity are reached (cooling stage), the processing unit program will control the maximum temperature difference between the test sample and the box environment to be less than or equal to 10℃, and the maximum humidity percentage difference to be less than or equal to 10%. When the temperature in the rapid cooling environment box 100 reaches the preset temperature value (error ±1℃), the humidity reaches the preset humidity value (error 1%), and the temperature error between the test sample and the environment box is ±1℃, and the humidity error is 2%, it is determined that the temperature and humidity of the test sample and the environment are consistent, and the test requirements are met.

[0060] S40, place the impactor in the projectile cabin 302 and seal it, and open the air compressor 301 to inject compressed air into the pressure cabin until the air pressure reaches the rated value.

[0061] Specifically, the impactor is placed in the detachable projectile holder, and then the detachable projectile holder is placed in the projectile cabin 302 and locked and sealed with the cover plate. The air compressor 301 is turned on to inject compressed air into the pressure cabin until the air pressure reaches the rated value.

[0062] S50, align the barrel outlet with the center position of the impactor incident port of the box body 3; launch the impactor, which is accelerated by high-pressure gas through the barrel 303 until it hits the test sample. In this process, the speedometer 400, the high-speed camera 600, and the strain acquisition system 500 all start working to synchronously acquire all test data of the impact process of the test sample.

[0063] Specifically, the electromagnetic valve is started, the impact object is accelerated by high-pressure gas pushing through the barrel 303 until it hits the sample, and in this process, the speedometer 400, the high-speed camera 600, the strain acquisition system 500 and the auxiliary detection system are all excited by the electromagnetic valve starting signal to start working, and all the test data of the sample impact process are synchronously acquired. In this process, the speedometer, the high-speed camera, and the strain acquisition system all start working, and all the test data of the sample impact process are synchronously acquired. The speedometer, the strain acquisition system, and the high-speed camera are excited by the electromagnetic valve starting signal to start synchronously, and the response delay is within 1 ms.

[0064] Preferably, after completing the high-speed impact test of the sample 9, the impact object is taken out through the impact object entrance door 7, and after replacing the disposable low-strength sealing and heat insulation film, the next impact test is waited for.

Claims

1. A high-speed impact testing system for foreign objects in rail vehicle components under low-temperature conditions, characterized in that, include: A rapid cooling environment chamber includes: a chamber body, one side of which is an openable and closable impactor inlet door, an adjustable position sliding mechanism, and stretchable parts connected to the left and right sides of the adjustable position sliding mechanism. The adjustable position sliding mechanism is equipped with a disposable low-strength sealing and heat insulation film, and the impactor inlet is located in the area of ​​the disposable low-strength sealing and heat insulation film. The inner walls of the other sides of the chamber body are covered 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 through an external channel to realize the conduction and transportation of the cooling medium. The inner wall of the chamber is equipped with a fixture for fixing the test piece to be installed; a high-speed camera is installed on the inner wall of the chamber; a temperature and humidity sensor for the test piece is pre-embedded inside the test piece during the experiment; the chamber is connected to a strain acquisition system for acquiring the strain response of the impact area. A rotating support base is located at the bottom of the box and is used to adjust the rotation angle of the box. A high-pressure air cannon system is used to provide a power source for an impactor. It includes an air cannon, an air compressor connected to the air cannon, a magazine mounted on the air cannon, and a cannon barrel connected to the magazine. A velocity measuring instrument is provided at one end of the cannon barrel outlet. When in use, the cannon barrel outlet is aligned with the impactor's inlet. The outer surface of the gun barrel is spirally wound with a liquid nitrogen condenser tube, which is connected to a self-pressurized liquid nitrogen tank; a pipe temperature and humidity sensor is installed on the outer surface of the gun barrel, and the pipe temperature and humidity sensor does not directly contact the liquid nitrogen condenser tube; a disposable low-strength sealing and heat insulation film is pasted on the outlet end of the gun barrel. The rotating support includes a fixed end, a rotating end, and a central pin. The fixed end is hinged to the rotating end via the central pin and is fixed to the ground by bolts. The rotating end has a rotational freedom of 0° to 75° and 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 distance the adjustable sliding mechanism travels at the impactor inlet is: L= Where H is the vertical distance from the impact point of the test piece to the plane of the impactor's inlet. The incident angle is specified. The disposable low-strength sealing and heat insulation film is made of flexible material and is glued to the inlet of the impactor. 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. The gun barrel outlet is aligned with the center point of the cross center mark. The stretchable part is a corrugated origami structure made of flexible heat insulation material.

2. The high-speed impact test system for foreign objects in rail vehicle components under low-temperature conditions according to claim 1, characterized in that, The chamber contains strain gauges, auxiliary test sensors, and a humidity regulator. The strain gauges are orthogonally distributed around the impact point, with a distance of 30mm to 100mm from the center point of the crosshair. The inner wall of the chamber is equipped with a data acquisition harness connector. One end of the data acquisition harness connector is connected to the ambient temperature and humidity sensor, strain gauges, and auxiliary test sensor, while the other end is connected to a temperature and humidity processing unit located outside the chamber. 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℃, and the maximum humidity percentage difference is less than 10%.

3. The high-speed impact test system for foreign objects in rail vehicle components under low-temperature conditions according to claim 1, characterized in that, The high-speed camera is networked through a microcomputer system to capture the entire morphology of the damage process at the impact location during the impact. The maximum sampling frequency of the high-speed camera system is 50,000 frames / second. The strain acquisition system is connected to the acquisition harness connector on the inner wall of the housing via a signal transmission line and is connected to the microcomputer system. The strain acquisition system has 16 channels and a maximum sampling frequency of 500,000Hz. The velocity meter is installed in front of the barrel exit and determines the velocity by measuring the passage time of the impacting object through the laser pulse interval. The velocity measurement accuracy is ±0.01m / s.

4. The high-speed impact test system for foreign objects in rail vehicle components under low-temperature conditions according to claim 1, characterized in that, The self-pressurized liquid nitrogen tank has a maximum volume of 200L. The outlet of the self-pressurized liquid nitrogen tank is equipped with two intelligent liquid nitrogen flow control valves, which are connected to the liquid nitrogen condenser tube inside the tank and the liquid nitrogen condenser tube in the gun barrel, respectively. The two intelligent liquid nitrogen flow control valves adjust the liquid nitrogen flow rate in real time by receiving temperature data from the temperature and humidity processing unit. The liquid nitrogen flow rate is steplessly adjustable within the range of 0L / min to 10L / min, with an adjustment accuracy of ±0.05L / min. When the temperature difference between the ambient temperature inside the tank 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 temperature and humidity of the ambient temperature and humidity inside the tank.

5. The high-speed impact test system for foreign objects in rail vehicle components under low-temperature conditions according to claim 1, characterized in that, The test specimen shall be equipped with no fewer than four temperature and humidity sensors, which shall be set at different locations on the test specimen. If the relative error of the temperature and humidity data monitored at different locations is within 2%, the test specimen shall be deemed to have reached a stable test state.

6. The high-speed impact test system for foreign objects in rail vehicle components under low-temperature conditions according to claim 1, characterized in that, The gun barrel and the impactor are installed and fitted together by a detachable sabot. The detachable sabot is petal-shaped with 4 to 6 equal parts. The outer contour of the detachable sabot fits the internal clearance of the gun barrel with a fit tolerance of 0.1mm to 0.3mm. The detachable sabot has a flared arc surface. The detachable sabot is made of lightweight foam material and weighs less than 20g. After the detachable sabot exits the gun barrel, it separates instantaneously under air resistance.

7. A high-speed impact test method using the high-speed foreign object impact test system for rail vehicle components under low-temperature conditions as described in any one of claims 1-6, comprising: Open the impactor entrance door of the rapid cooling environment chamber, install the test sample on the test piece fixing fixture and lock it in place, connect all the sensor signal lines to the acquisition harness connector on the side wall of the environment chamber through quick-connect plugs, and then lock the impactor entrance door. Adjust the angle of the box by rotating the support base, and then move the stretchable part to adjust the center position of the impactor inlet to the preset position; Set the ambient temperature and humidity parameters and start the cooling and humidity adjustment program to meet the test requirements; Place the impactor inside the bomb bay and seal it. Turn on the air compressor to inject compressed air into the pressure chamber until the air pressure reaches the rated value. The gun barrel outlet is aligned with the center of the impactor inlet of the test chamber; the impactor is launched and accelerated through the gun barrel by high-pressure gas until it impacts the test sample. During this process, the velocimeter, high-speed camera, and strain acquisition system all start working and simultaneously acquire all test data of the impact process of the test sample. The velocimeter, strain acquisition system, and high-speed camera are activated synchronously by the solenoid valve start signal, and the response delay is within 1ms.

Images