Temperature- and humidity-controlled performance testing apparatus for impact protective material

Abstract

Disclosed in the present invention is a temperature- and humidity-controlled performance testing apparatus for an impact protective material, the apparatus comprising an environmental conditioning unit, an impact experiment unit, a numerical control system and a sample clamping apparatus, wherein the environmental conditioning unit comprises an environmental chamber, a steam generator and a water tank; the impact experiment unit is used for applying an impact load to a sample and measuring the mechanical properties thereof; the sample clamping apparatus is located in the environmental chamber and is used for evaluating the protection level of the sample; and the numerical control system is used for coordinating the position of the sample, controlling test temperature and humidity, and temperature and humidity durations, and also collecting data and outputting a curve. The present invention can simulate different impact environments, such that experimental conditions are closer to the real application environment of an impact protective material in a fire scene and a battlefield. By means of the instrument, the angle and position at which a sample undergoes an impact can be flexibly adjusted; and on the basis of piezoelectric and acceleration sensors under a chest-wall-simulating clamping apparatus, the injury situation of a protected human body after undergoing an impact can be calculated.

Description

Temperature and humidity controllable impact protective material performance testing device TECHNICAL FIELD

[0001] The present application relates to the field of material mechanical property testing, and belongs to the instrument and meter class, in particular to an impact protective material impact load experiment system, and particularly relates to a temperature and humidity controllable impact protective material performance testing device. BACKGROUND

[0002] Impact protective equipment is a necessary protective barrier for special operating personnel such as firefighters and soldiers during their service, and it is of great significance to evaluate its performance in complex operating environments. However, many studies have shown that materials with strong shock wave attenuation ability such as copper plates and ceramic plates exhibit completely opposite effects when they are used as human body impact protective equipment. This phenomenon is related to the impedance matching mechanism of the material itself when it is subjected to impact and the backward movement of the material caused by the impact load. Therefore, the mechanical property testing of the material alone cannot intuitively determine the strength of its protective ability. According to the YELVERTON explosion injury pathology scoring system in the United States, the damage to each organ of the animal in the explosion is expressed by a trauma score, and the corrected injury severity ASII value is obtained, which can not only evaluate the lung damage but also evaluate other tissues and organs, and has a wide range of applications. At present, the most accurate way to predict human impact injury is the injury prediction based on chest wall velocity. Axelsson et al. established the relationship between human chest and abdominal explosion injury and (adjusted injury of severity index, ASII) score, maximum chest wall movement velocity v, which means that if the equivalent chest wall movement velocity can be obtained at the same time when the material is measured, the strength of the material protective ability can be more accurately inferred.

[0003] Studies have shown that the most common type of impact encountered by coal miners and firefighters during their service is low-velocity impact caused by falling objects or fragments. Experimental methods capable of simulating low-velocity impacts include pendulum impact tests and falling weight impact tests. Among these, the falling weight test apparatus can simulate common fragment and falling object impacts, providing a better measure of the three-dimensional impact resistance of materials. However, due to the poor heat resistance of the sensors in the falling weight's hammer head, although some falling weight devices can conduct impact tests at high temperatures, the samples are often placed in a high-temperature chamber and transported to the loading device for testing after reaching the required temperature. This limits the temperature range and data accuracy. Besides simple temperature control, currently no instruments can simultaneously control the temperature and humidity of the impact scenario, nor can they control the position and angle of the impact on the sample, failing to meet my country's current needs for evaluating the impact resistance of impact protection materials in complex environments. Furthermore, the data transmitted by existing instruments can only assess the mechanical properties of the material itself, not its protective effect on the protected structure, making it difficult to provide reference data for the design optimization of protective materials.

[0004] Since conducting field impact disaster scenario tests on complete garments is more costly, accurately evaluating the protective performance of protective gear materials under small-scale conditions is of practical significance for the design and optimization of impact protection equipment. Therefore, an impact testing system capable of simulating complex impact environments such as high temperature and high humidity is needed to achieve precise evaluation of the impact resistance and impact protection performance of materials. Summary of the Invention

[0005] To address the technical problems existing in the background art described above, the present invention provides a temperature and humidity controllable impact protection material performance testing device.

[0006] A temperature and humidity controllable impact protection material performance testing device includes an environmental conditioning unit, an impact testing unit, a CNC system, and a sample clamping device.

[0007] The environmental control unit includes an environmental chamber, a steam generator, and a water tank. Radiation heat sources are provided on both sides of the environmental chamber, and a steam inlet is provided connected to the steam generator to regulate the humidity inside the chamber.

[0008] The impact test unit is coupled to the environmental chamber and includes a frame, guide column, drop hammer slidably connected to the guide column, steering shaft, steering coupling rod, drop hammer lifting mechanism and transient force and displacement testing device, used to apply impact load to the sample and measure its mechanical properties;

[0009] The sample clamping device is located inside the environmental chamber and consists of a positioning clamping rod, a PDMS skin-like film, a transient velocity sensor, a piezoelectric sensor, and a rubber pad, and is used to evaluate the protection level of the sample.

[0010] The numerical control system comprises a central control console and an output end, and is used for coordinating a test sample position, controlling a test temperature and humidity and a temperature and humidity duration; meanwhile, data are collected, and a stress-strain curve of the sample in the impact test and a speed-time curve and a stress-strain curve of the clamping platform are output.

[0011] As a further technical scheme of the present application, the environmental box is a cuboid, and comprises a front door plate, a fixed shell, a base and an end cover plate, the front door plate and the end cover plate are both openable and closable relative to the fixed shell, and the inner wall of the box body of the environmental box is provided with a heat preservation layer; radiation heat sources are arranged on both sides of the box body, the radiation heat sources are composed of quartz lamp tubes and are electrically connected with the central control console, the back side of the box body of the environmental box is provided with a closable steam inlet hole, the steam inlet hole is electrically connected with the central control console, the central control console is provided with a radiation heat intensity adjusting knob and a steam inlet hole opening and closing knob, and the temperature and humidity in the environmental box can be adjusted; the steam inlet hole is connected with a steam generator outlet pipe, the steam generator is provided with a gas pump, a switch and a gas pressure balance valve, steam can be generated and delivered to the inside of the environmental box, the steam generator is connected with a water tank through a conduit, the environmental box is provided with a visual temperature and humidity sensor which is electrically connected with the central control console, the base is provided with a lower slide rail above, a sample clamping device is arranged on the lower slide rail, and a moving motor is arranged below to drive the sample to move on the lower slide rail.

[0012] As a further technical scheme of the present application, the impact test unit comprises a rack, a drop hammer support frame, a stand, a steering shaft and a steering coupling rod, a guide column, a drop hammer which is slidably connected with the guide column, a drop hammer lifting mechanism and a transient force and displacement testing device, wherein the drop hammer lifting mechanism is composed of a servo motor and an electromagnetic brake, the transient force and displacement testing device comprises a sensor support sleeve, a piezoelectric force sensor and a charge amplifier, the charge amplifier is electrically connected with the output end, the sensor support sleeve is mounted on the upper end of the hammer head of the drop hammer, the piezoelectric force sensor is located in the sensor support sleeve and is connected with the charge amplifier, the guide column is a circular rod structure, the drop hammer is connected with a mounting seat which is sleeved on the guide column, and an electromagnet is arranged below the mounting seat.

[0013] As a further technical scheme of the present application, the central control console and the output end jointly constitute a numerical control system, the numerical control system is electrically connected with the visual temperature and humidity sensor, the radiation heat source and the steam inlet hole, and functions to control test conditions, control test start and end, and output effective data.

[0014] As a further technical scheme of the present application, the sample clamping device is located in the environmental box and is composed of a positioning clamping rod, a PDMS skin film, a transient velocity sensor, a piezoelectric sensor and a rubber pad; the clamping platform is used for simulating the injury degree of the human chest wall, the PDMS skin film constitutes the upper layer of the clamping platform, the positioning clamping rod is used for fixing the sample, the transient velocity sensor and the piezoelectric sensor are located below the PDMS skin film, the lower layer of the transient velocity sensor and the piezoelectric sensor is the rubber pad with the same density as the human muscle, and the clamping platform below is connected with the moving motor through the universal shaft.

[0015] The present application has the following beneficial effects:

[0016] The present application can control the temperature and humidity of the sample in the impact environment through the environmental box, control the angle of the falling hammer through the turning shaft and the double-sided guide column, simulate different impact environments, and make the experimental conditions closer to the real application environment of the impact protection material in the fire field and the battlefield. The instrument can realize flexible adjustment of the impact angle and position of the sample, and according to the piezoelectric and acceleration sensors below the chest wall clamping device, the injury condition of the protected human body after being impacted can be calculated under small-scale conditions. The present application has high integration, can test and observe the mechanical response and damage mechanism of the anti-impact material in the complex hot and humid environment, and realize the evaluation of the protection performance of the material. BRIEF DESCRIPTION OF DRAWINGS

[0017] Fig. 1 is a schematic diagram of the overall structure of the device of the present application.

[0018] Fig. 2 is a detail view of the environmental adjustment unit of the present application.

[0019] Fig. 3 is a detail view of the impact unit of the present application.

[0020] Fig. 4 is a detail view and front view of the sample clamping device of the present application.

[0021] Fig. 5 is a detail view of the turning shaft and the turning coupling rod of the sample clamping device of the present application.

[0022] Figure Labels and Annotations: 1-Environmental Control Unit, 2-Environmental Chamber, 3-Steam Generator, 4-Water Tank, 5-Front Door Panel, 6-Fixed Housing, 7-Base, 8-End Cover, 9-Insulation Layer, 10-Radiant Heat Source, 11-Central Control Panel, 12-Steam Inlet, 13-Radiant Heat Intensity Adjustment Knob, 14-Steam Inlet Opening / Closing Knob, 15-Steam Generator Outlet Pipe, 16-Air Pump, 17-Switch, 18-Pressure Balance Valve, 19-Conduit, 20-Data Acquisition Wire, 21-Visual Temperature and Humidity Sensor, 22-Lower Slide Rail, 23-Sample Clamping Device 24-Mobile motor, 25-Impact test unit, 26-Frame, 27-Falling hammer support frame, 28-Column, 29-Guide column, 30-Falling hammer, 31-Falling hammer lifting mechanism, 32-Sensor support sleeve, 33-Piezoelectric sensor, 34-Charge amplifier, 35-Output terminal, 36-Mounting base, 37-Electromagnet, 38-CNC system, 39-Positioning clamping rod, 40-PDMS skin-like film, 41-Transient velocity sensor, 42-Piezoelectric sensor, 43-Rubber pad, 44-Universal shaft, 45-Sample, 46-Steering shaft, 47-Steering coupling rod. Detailed Implementation

[0023] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings.

[0024] Please refer to Figures 1 to 5. This embodiment of the invention provides a temperature and humidity controllable impact protection material performance testing device, including an environmental conditioning unit 1, an impact test unit 25, a numerical control system 38, and a sample clamping device 23.

[0025] The environmental control unit 1 includes an environmental chamber 2, a steam generator 3, and a water tank 4. Radiation heat sources 10 are provided on both sides of the interior of the environmental chamber 2, and a steam inlet 12 is provided and connected to the steam generator 3 for regulating the humidity inside the chamber.

[0026] The impact test unit 25 is coupled to the environmental chamber 2 and includes a frame 26, a guide post 29, a steering shaft 46, a steering coupling rod 47, a drop hammer 30 slidably connected to the direction-adjustable guide post 29, a drop hammer lifting mechanism 31, and a transient force and displacement testing device, which is used to apply impact load to the sample and measure its mechanical properties.

[0027] The sample clamping device 23 is located inside the environmental chamber 2 and consists of a positioning clamping rod 39, a PDMS skin-like film 40, a transient velocity sensor 41, a piezoelectric sensor 42, and a rubber pad 43. It is used to evaluate the protection level of the sample.

[0028] The numerical control system 38 includes a central control console 11 and an output end 35, which are used for coordinating the test position, controlling the test temperature and humidity and the temperature and humidity duration; meanwhile, data are collected, and the stress-strain curve of the sample in the impact test and the speed-time curve and stress-strain curve of the clamping platform are output.

[0029] The environmental box 2 of the embodiment is a cuboid, which comprises a front door plate 5, a fixed shell 6, a base 7 and an end cover plate 8, the front door plate 5 and the end cover plate 8 are both openable and closable relative to the fixed shell 6, the front door plate 5, the fixed shell 6 and the end cover plate 8 are all made of temperature-resistant steel plates, the base 7 is made of heat-insulating bricks with buffering performance, the inner wall of the box body of the environmental box 2 is provided with a heat-insulating layer 9 made of ceramic bricks wrapped with heat-insulating enzymes, both sides in the box body of the environmental box 2 are provided with radiation heat sources 10 made of quartz lamp tubes and electrically connected with the central control console 11, the quartz tubes can generate radiation heat with different heat flux densities, simulate various fire environments in which workers in the petroleum and chemical industry or firefighters are trapped, the back side of the box body of the environmental box 2 is provided with closable steam air inlets 12 electrically connected with the central control console 11, the central control console 11 is provided with a radiation heat intensity adjusting knob 13 and a steam air inlet opening and closing knob 14, which can be used for adjusting the temperature and humidity in the environmental box 2, the steam air inlets 12 are connected with steam generator outlet pipes 15, the steam generator 3 is provided with an air pump 16, a switch 17 and an air pressure balancing valve 18, which can generate steam to be delivered to the inside of the environmental box 2, the steam generator 3 is connected with a water tank 4 through a conduit 19, the environmental box 2 is provided with visual temperature and humidity sensors 21 electrically connected with the central control console 11, which are used for real-time detection and control of the temperature and humidity in the box, the lower part of the base 7 is provided with a lower slide rail 22, a sample clamping device 23 is located on the lower slide rail 22, and a moving motor 24 is arranged below the lower slide rail 22, which can drive the sample to move on the lower slide rail 22.

[0030] The impact test unit 25 of the embodiment comprises a rack 26, a drop hammer support frame 27, a stand column 28, guide columns 29 distributed on both sides of the stand column 26, a drop hammer 30 slidably connected with the guide columns 29, a steering shaft 46 for controlling the coupling of the drop hammer and the guide columns, a steering coupling rod 47, a drop hammer lifting mechanism 31 composed of a servo motor and an electromagnetic brake, and a transient force and displacement testing device, the transient force and displacement testing device comprises a sensor support sleeve 32, a piezoelectric force sensor 33 and a charge amplifier 34, the charge amplifier 34 is electrically connected with an output end 35, the sensor support sleeve 32 is installed on the upper end of the hammer head of the drop hammer 30, the piezoelectric force sensor 33 is located in the sensor support sleeve 32 and connected with the charge amplifier 34, the guide column 29 is a circular rod structure, the drop hammer 30 is connected with a mounting seat 36 sleeved on the guide column 29, and an electromagnet 37 is arranged below the mounting seat 36.

[0031] In this embodiment, the central control console 11 and the output terminal 35 together constitute a numerical control system 38. The numerical control system 38 is electrically connected to the visual temperature and humidity sensor 21, the radiant heat source 10 and the steam inlet 12. Its function is to control the experimental conditions, control the start and end of the experiment, and output valid data.

[0032] The sample clamping device 23 described in this embodiment is located inside the environmental chamber 2 and consists of a positioning clamping rod 39, a PDMS skin-like film 40, a transient velocity sensor 41, a piezoelectric sensor 42, and a rubber pad 43. The clamping platform is used to simulate the degree of injury to the human chest wall. The PDMS skin-like film 40 forms the upper layer of the clamping platform. The positioning clamping rod 39 is used to fix the sample. The transient velocity sensor 41 and the piezoelectric sensor 42 are located below the PDMS skin-like film 40. The lower layer of the transient velocity sensor 41 and the piezoelectric sensor 42 is a rubber pad 43 with the same density as human muscle. The clamping platform is connected to the moving motor 24 through a universal joint 44. The impact direction of the sample can be adjusted by adjusting the universal joint 44.

[0033] The above-mentioned temperature and humidity controllable impact protection material performance testing device includes the following steps in its implementation:

[0034] Step 1: Adjust the height and counterweight of the drop hammer 30, input the required impact load or impact speed in the instrument control panel 11, adjust the steering shaft 46 to couple the steering coupling rod 47 with the guide post 29 on one side; preset the heat flux density and steam input time in the control panel 11 according to the required experimental temperature and humidity, and set the sample temperature and humidity conditioning time according to the experimental requirements.

[0035] Step 2: Close the end cover 8 of the environmental chamber 2, fix the sample on the sample clamping device 23, determine the clamping angle of the sample, open the radiant heat source 10 and the steam inlet 12 through the radiant heat intensity adjustment knob 13 and the steam inlet opening and closing knob 14 on the central control panel 11, turn on the switch 17 of the steam generator 3, so that the steam can reach the interior of the environmental chamber 2 through the steam inlet 12, balance the internal air pressure of the instrument through the air pressure balance valve 18, observe the reading of the visual temperature and humidity sensor 21, and wait for the temperature and humidity inside the chamber to reach the specified values.

[0036] Step 3: Adjust the position of the sample in the environmental chamber 2 by controlling the moving motor 24 under the sample clamping device 23, and control the lifting of the hammer head of the drop hammer 30 to the specified height by controlling the central control panel 11;

[0037] Step 4: Pull out the end cover plate 8 of the environmental chamber 2, calibrate the relative position of the hammer and the sample, adjust the steering shaft 46 and move the sample along the lower slide rail 22, adjust the universal joint 44 of the clamping device to calibrate the impact angle, and align the hammer position with the sample position.

[0038] Step 5: The drop hammer 30 is controlled to drop and contact the sample 45 by the center console 11, and then the anti-secondary impact electromagnet 37 captures the hammer head, and the experiment ends; the piezoelectric force sensor 33 outputs the real-time load on the sample surface and the stress-strain curve of the sample through the output end 35, and the transient velocity sensor 41 and the piezoelectric sensor 42 output the velocity-time curve and the stress-strain curve of the protected structure through the data acquisition wire 20;

[0039] Step 6: According to the real-time velocity-time curve and the stress-strain curve of the protected structure output by the transient velocity sensor 41, the equivalent human injury degree is calculated by using formula 1;

[0040] Formula 1: ;

[0041] Wherein ASII is the impact injury severity index, and v is the chest wall-like movement speed (m / s) measured by the sensor under the PDMS skin-like film 40; according to the ASII and v, the injury classification can be evaluated; and according to Table 1, the approximate injury situation of the human body under the protection of the material after facing the impact load can be evaluated;

[0042] Table 1 Relationship between Axelsson injury classification and ASII number and v

[0043] Injury level ASII v / (m.s -1 ) No injury 0~0.2 3.6~3.6 Mild injury to slight injury 0.2~1.0 3.6~7.5 Slight injury to moderate injury 0.3~1.9 4.3~9.8 Moderate injury to severe injury 1.0~7.1 7.5~16.9 >50% mortality >3.6 >12.8

[0044] Step 7: End the experiment, get the experimental curves from the numerical control system; turn off the steam generator 3, pull out the air pressure balance valve 18 to balance the air pressure in the steam generator 3, close the steam inlet hole 12, close the radiant heat source 10, open the front door plate 5 of the environmental box 2, and wait for the environmental box 2 to cool naturally. If you need to continue testing, start the next round of experiment from step 1, and adjust the steering shaft 46 to change the angle of the drop hammer in the subsequent experiment.

[0045] The present application can control the temperature and humidity of the impact experiment through the environmental box 2, simulate different impact environments, and control the impact position and angle of the material through the steering shaft 46 combined with the slide rail 22 and the sample clamping device 23. The PDMS skin film 40 and the muscle-like rubber, i.e. rubber pad 43, are combined to make the main body of the sample clamping device 23, so that the instrument can not only measure the impact response of the material itself, but also obtain the protection effect on the human body. The different temperature and humidity conditions simulated by the environmental box 2 correspond to the different external environments that the protective equipment needs to face, and the position and angle of the sample clamping device 23 correspond to the actual angle and force condition of the equipment when it is impacted. According to the external environment requirement, the experimental conditions are more accurately defined, which can improve the accuracy of the mechanical properties and protection performance test of the anti-impact material and equipment, reduce the cost of the overall protection performance test of the equipment. It has important significance for the research and development and evaluation of human body anti-impact protective equipment.

[0046] The above is only the preferred embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent process transformation using the content of the specification and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A temperature and humidity controllable impact protective material performance testing device, characterized in that, The application relates to an environmental regulation unit, an impact experiment unit, a numerical control system and a sample clamping device. The environmental regulation unit comprises an environmental box, a steam generator and a water tank; radiation heat sources are arranged on the two sides in the box body of the environmental box; and a steam inlet hole is arranged on the environmental box and connected with the steam generator, so as to regulate the humidity in the box. The impact experiment unit is coupled with the environmental box and comprises a rack, a guide column, a hammer connected with the guide column in a sliding mode, a steering shaft, a steering coupling rod, a hammer lifting mechanism and a transient force and displacement testing device, which are used for applying impact load to the sample and measuring the mechanical properties of the sample. The sample clamping device is arranged in the environmental box and comprises a positioning and clamping rod, a PDMS skin film, a transient speed sensor, a piezoelectric sensor and a rubber pad, which are used for evaluating the protection level of the sample. The numerical control system comprises a central control console and an output end, which are used for coordinating the sample position, controlling the test temperature and humidity and the temperature and humidity duration; meanwhile, data are collected, and the stress-strain curve of the sample in the impact experiment and the speed-time curve and the stress-strain curve of the clamping platform are output.

2. The temperature and humidity controllable impact protective material performance testing device according to claim 1, wherein, The environmental box is in the shape of a cuboid, and the environmental box comprises a front door plate, a fixed shell, a base and an end cover plate; the front door plate and the end cover plate can be opened and closed relative to the fixed shell; the inner wall of the box body of the environmental box is provided with a heat preservation layer; radiation heat sources are arranged on the two sides in the box body of the environmental box and are composed of quartz lamp tubes and are electrically connected with the central control console; the back side of the box body of the environmental box is provided with a closable steam inlet hole which is electrically connected with the central control console; the central control console is provided with a radiation heat intensity adjusting knob and a steam inlet hole opening and closing knob, so that the temperature and humidity in the environmental box can be adjusted; the steam inlet hole is connected with a steam outlet pipe of a steam generator; the steam generator is provided with an air pump, a switch and an air pressure balance valve, so that steam can be generated and delivered to the inside of the environmental box; the steam generator is connected with a water tank through a pipeline; the environmental box is provided with a visual temperature and humidity sensor which is electrically connected with the central control console; the base is provided with a lower slide rail above; the sample clamping device is arranged on the lower slide rail; and a moving motor is arranged below, so as to drive the sample to move on the lower slide rail.

3. The temperature and humidity controllable impact protective material performance testing device according to claim 2, wherein, The impact experiment unit comprises a rack, a hammer support frame, a stand, a steering shaft, a steering coupling rod, a guide column with adjustable impact direction, a hammer connected with the guide column in a sliding mode, a hammer lifting mechanism and a transient force and displacement testing device; the transient force and displacement testing device comprises a sensor support sleeve, a piezoelectric force sensor and a charge amplifier; the charge amplifier is electrically connected with a signal output end; the sensor support sleeve is mounted on the upper end of the hammer head of the hammer; the piezoelectric force sensor is arranged in the sensor support sleeve and is connected with the charge amplifier; the guide column is in the shape of a circular rod; the hammer is connected with a mounting seat which is sleeved on the guide column; and an electromagnet is arranged below the mounting seat.

4. The temperature and humidity controllable impact protective material performance testing device according to claim 3, wherein, The central control console and the output end jointly constitute a numerical control system; the numerical control system is electrically connected with the visual temperature and humidity sensor, the radiation heat source and the steam inlet hole; and the numerical control system is used for controlling the experimental conditions, controlling the start and end of the experiment and outputting effective data.

5. The temperature and humidity controlled impact protective material performance testing apparatus of claim 4, wherein, The sample clamping device is located in an environmental box and is composed of a positioning clamping rod, a PDMS skin film, a transient speed sensor, a piezoelectric sensor and a rubber pad; a clamping platform is used for simulating the injury degree of the human chest wall, the PDMS skin film constitutes the upper layer of the clamping platform, the positioning clamping rod is used for fixing the sample, the transient speed sensor and the piezoelectric sensor are located below the PDMS skin film, the lower layer of the transient speed sensor and the piezoelectric sensor is the rubber pad with the same density as the human muscle, and the clamping platform below is connected with a moving motor through a universal shaft.

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