Automatic testing device and method for surface emissivity of fiber reinforced composite material

Abstract

The application discloses a kind of fiber reinforced composite surface emissivity automatic testing device and method, belong to infrared temperature measurement field, wherein device includes non-contact infrared temperature measurement component, multiple degrees of freedom rotating table, heating and contact type temperature measurement component, non-contact infrared temperature measurement component includes infrared camera, infrared camera is connected with computer, multiple degrees of freedom rotating table includes lower rotating table, upper rotating table, heating and contact type temperature measurement component includes adjustable DC power supply, temperature tester, adjustable DC power supply is connected with ceramic heating sheet, ceramic heating sheet is set on upper rotating table, ceramic heating sheet is provided with fiber reinforced composite prepreg tape sample, fiber reinforced composite prepreg tape sample surface is provided with thermocouple, thermocouple is connected with temperature tester.The application uses above-mentioned device and method, can solve the emissivity of fiber reinforced composite material under different temperature, observation angle and fiber orientation angle, which cannot be automatically tested in prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of infrared temperature measurement, in particular to a device and method for automatically testing the emissivity of a fiber-reinforced composite material surface. BACKGROUND

[0002] Fiber-reinforced composite materials are a kind of composite materials in which fibers are used as reinforcing phases and thermoplastic or thermosetting polymers are used as matrices to bond the fibers together. They combine the advantages of reinforcing materials and matrices and exhibit the characteristics of lightweight and high strength, and are widely used in the fields of aerospace, automobiles, industrial products, etc. In the manufacturing process of composite materials, this kind of material is usually provided in the form of a prepreg tape. Automatic fiber placement technology is an advanced technology for manufacturing composite materials, which controls the movement of a six-axis robot through programming and drives the precise movement of a placement head to automatically place a composite prepreg tape. It can realize the rapid and high-precision processing and manufacturing of complex composite structural parts. The interlayer bonding of the composite prepreg tape is achieved by melting the thermoplastic resin or curing the thermosetting resin through laser or hot gas torch heating, and the interlayer consolidation is realized under the action of a compression roller. The heating temperature is crucial for the molding of composite materials. Too high a temperature may cause ablation or evaporation of the resin, while too low a temperature may result in reduced interlayer bonding, which will form internal defects in the composite structural part and seriously affect the mechanical properties of the material. The contact temperature measurement method such as thermocouple measurement is accurate but will affect the molding process of the material. Therefore, when processing fiber-reinforced composite materials with automatic fiber placement technology, a non-contact infrared camera is usually used for real-time monitoring of temperature and defects, and the accuracy of infrared camera temperature measurement depends greatly on the setting of its emissivity. The closer the emissivity is to the actual emissivity of the measured material, the higher the accuracy of infrared camera temperature measurement. Usually, the value is set to 1 by default in the infrared camera, but in fact the emissivity of fiber-reinforced composite materials is affected by many factors. There are great differences in the emissivity of the material at different temperatures, different observation angles and different fiber orientations, especially at high temperatures and large observation angles. Without calibration, the emissivity of the infrared camera will cause the temperature measurement result to deviate greatly from the actual surface temperature of the material. Therefore, an effective method is needed to measure the actual emissivity of the composite material at different temperatures, different observation angles and different fiber orientations and to calibrate the emissivity of the infrared camera in real time, so as to realize accurate measurement of the surface temperature of the composite material under processing conditions and improve the quality of the composite structural part.

[0003] The traditional Fourier infrared spectrum measurement method can obtain continuous emissivity values of a material at different wavelengths, but the emissivity obtained by the method is a one-to-one corresponding result of the wavelength and the emissivity in a wide wave band, and the emissivity of the material obtained in different wave bands is different, so that a suitable result cannot be selected to measure the actual emissivity of the material. In addition, the method is limited to the observation angle perpendicular to the sample, and the infrared camera is not perpendicular to the sample for testing in actual processing, but is at a certain angle with the sample surface, so that the traditional Fourier infrared measurement method cannot measure the surface emissivity of the material at multiple observation angles, although the accuracy is high. SUMMARY

[0004] The purpose of the present application is to provide a fiber-reinforced composite material surface emissivity automatic testing device and method, which solves the problem that the prior art cannot automatically test the emissivity of fiber-reinforced composite materials at different temperatures, observation angles and fiber orientation angles.

[0005] To achieve the above-mentioned purpose, the present application provides a fiber-reinforced composite material surface emissivity automatic testing device, which comprises a non-contact infrared temperature measurement assembly, a multi-degree-of-freedom rotating table, a heating and contact type temperature measurement assembly, the non-contact infrared temperature measurement assembly comprises an infrared camera, the infrared camera is connected with a computer, the multi-degree-of-freedom rotating table is arranged in the direction of the lens of the infrared camera, the multi-degree-of-freedom rotating table comprises a lower rotating table with horizontal direction rotating function and an upper rotating table with vertical direction rotating function, the heating and contact type temperature measurement assembly comprises an adjustable direct current power supply and a temperature tester connected with the computer, the adjustable direct current power supply is connected with a ceramic heating sheet, the ceramic heating sheet is arranged on the upper rotating table, a fiber-reinforced composite material prepreg strip sample is arranged on the ceramic heating sheet, a thermocouple is arranged on the surface of the fiber-reinforced composite material prepreg strip sample, and the thermocouple is connected with the temperature tester.

[0006] Preferably, the infrared camera and the multi-degree-of-freedom rotating table are arranged on a support plate.

[0007] Preferably, the lower rotating table is arranged below the upper rotating table, and the lower rotating table and the upper rotating table are driven to rotate by servo motors, and the servo motors are connected with the computer.

[0008] Preferably, a spring clamping piece is arranged on the upper rotating table, and the ceramic heating sheet is fixed to the upper rotating table through the spring clamping piece.

[0009] Preferably, the fiber-reinforced composite material prepreg strip sample is pasted on the ceramic heating sheet through a high-temperature resistant adhesive tape.

[0010] Preferably, the thermocouple is fixed on the surface of the fiber-reinforced composite material prepreg strip sample through a high-temperature resistant adhesive tape and a flat clamp.

[0011] The application provides a kind of fiber reinforced composite surface emissivity automatic testing device method, comprising the following steps:

[0012] Step one, the fixation and placement of fiber reinforced composite: the fiber reinforced composite prepreg sample is pasted on the ceramic heating sheet with high-temperature-resistant tape, the thermocouple is fixed on the surface of the fiber reinforced composite prepreg sample with high-temperature-resistant tape and fixed with a flat clamp, and then the ceramic heating sheet and the fixed fiber reinforced composite prepreg sample are placed in the spring clamp on the upper rotating table.

[0013] Step two, each structure connection: the adjustable DC power supply is connected to the ceramic heating sheet through wires, the thermocouple is connected to the temperature tester, the temperature tester is connected to the computer through wired network, the multi-degree-of-freedom rotating table is connected to the computer through wired network, and the infrared camera is connected to the computer through wired network.

[0014] Step three, automatic emissivity measurement: the environmental parameters are pre-calibrated by the computer, the infrared camera lens is calibrated, the position of the multi-degree-of-freedom rotating table or the infrared camera is adjusted to make the observation area of the fiber reinforced composite prepreg sample located in the center of the imaging interface, the temperature of the fiber reinforced composite prepreg sample is measured at the interface, the actual temperature measuring point is selected near the thermocouple, the voltage required for setting the target temperature is opened by the adjustable DC power supply, the temperature tester is opened, the actual temperature of the surface of the fiber reinforced composite prepreg sample is recorded, after reaching the target temperature, the infrared camera automatically starts adjusting the emissivity through the computer, so that the temperature measured by the infrared camera is consistent with the temperature measured by the temperature tester connected to the thermocouple, and the emissivity value of the infrared camera at this time is recorded as the actual emissivity of the fiber reinforced composite prepreg sample at this temperature.

[0015] Step four, adjust the voltage to change the temperature and repeat the test process in step three to obtain the emissivity of the fiber reinforced composite prepreg sample at different temperatures.

[0016] Step five, under the condition that the temperature does not change, the angle of the multi-degree-of-freedom rotating table is adjusted to obtain the emissivity of the fiber reinforced composite prepreg sample at different angles.

[0017] Preferably, the flat clamp is wrapped with high-temperature-resistant tape at the head end.

[0018] Preferably, in step three, the environmental parameters include test distance, test environment temperature and humidity.

[0019] Preferably, in step five, the observation angle of the infrared camera to the fiber reinforced composite prepreg sample is changed by adjusting the lower rotating table of the multi-degree-of-freedom rotating table, and the orientation angle of the fiber reinforced composite prepreg sample is changed by adjusting the upper rotating table of the multi-degree-of-freedom rotating table.

[0020] Therefore, the application adopts the above-mentioned automatic testing device and method for surface emissivity of fiber-reinforced composite material, and has the following beneficial effects:

[0021] The application realizes automatic collection of the emissivity of the fiber-reinforced composite material by connecting the infrared camera with the computer, adjusts the voltage to change the temperature by the adjustable direct-current power supply, changes the observation angle of the infrared camera and the fiber orientation angle of the sample by the multi-degree-of-freedom rotary table driving the fiber-reinforced composite prepreg sample to rotate, obtains the emissivity of the fiber-reinforced composite material under different temperatures, observation angles and fiber orientation angles, and reduces the repetition and time consumption compared with manual calibration of the emissivity of the infrared camera, greatly improves the monitoring efficiency, and provides a fast measurement method for studying the influence of the state of the fiber-reinforced composite material on the emissivity.

[0022] The technical solutions of the application will be further described in detail below with reference to the drawings and embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 FIG. 1 is a schematic diagram of the overall structure of the automatic testing device for surface emissivity of fiber-reinforced composite material according to the embodiment of the application.

[0024] Figure 2 FIG. 4 is a schematic diagram of the structure of the multi-degree-of-freedom rotary table according to the embodiment of the application.

[0025] REFERENCE NUMERALS

[0026] 1, computer; 2, servo motor; 3, infrared camera; 4, fiber-reinforced composite prepreg sample; 5, ceramic heating sheet; 6, support plate; 7, base; 8, connecting seat; 9, adjustable direct-current power supply; 10, temperature tester; 11, lower rotary table; 12, flat mouth clamp; 13, spring clamp; 14, upper rotary table. DETAILED DESCRIPTION

[0027] In order to make the purposes, technical solutions and advantages of the embodiments of the application more clear, the embodiments of the application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the embodiments of the application, and are not used to limit the embodiments of the application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application. The examples of the embodiments are shown in the drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout.

[0028] It is to be understood that the terms "including", "containing", "having" and variations thereof herein are intended to be open-ended terms that specifically permit for the inclusion of other steps, elements, components, members, etc. that are not expressly listed, so long as such steps, elements, components, members, etc. do not exclude other steps, elements, components, members etc.

[0029] Like reference numerals and letters in the various figures indicate like items, and thus, once any item is defined in one figure, it should not require further discussion in subsequent figures.

[0030] In the description of the present application, it should be noted that the terms "upper", "lower", "inner", "outer", and the like, indicate relative positions or orientation relationships based on the positions or orientation relationships shown in the drawings, or the positions or orientation relationships in which the products of the present application are usually placed, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0031] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "arranged", "mounted", "connected" should be understood broadly, for example, can be fixedly connected, or can be detachably connected, or integrally connected; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium, or can be connected internally between two elements. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0032] Embodiment

[0033] As shown in Figure 1 The present application discloses a kind of fiber reinforced composite material surface emissivity automatic testing device, including non-contact infrared temperature measurement component, multi-degree-of-freedom rotating table, heating and contact temperature measurement component.Its principle is mainly by comparing thermocouple connection temperature tester 10 temperature measurement result and infrared camera 3 temperature measurement result, through computer 1 control adjustment emissivity size makes both equal, to obtain the emissivity value of material that can accurately reflect the actual temperature of material surface under different conditions.

[0034] Non-contact infrared temperature measurement component includes infrared camera 3, infrared camera 3 is connected with computer through wired network, infrared camera 3 is installed on support plate 6.Computer 1 controls infrared camera 3, realizes the accurate configuration of infrared camera 3 parameter, and this parameter is mainly related to environmental parameter and emissivity.

[0035] The multi-degree-of-freedom rotating table is installed on the support plate 6, and the multi-degree-of-freedom rotating table can be located in the observation direction of the lens of the infrared camera 3 by adjusting the position of the infrared camera 3 or the multi-degree-of-freedom rotating table on the mounting plate. Figure 2 As shown in the figure, the multi-degree-of-freedom rotating table includes a lower rotating table 11 with horizontal direction rotating function and an upper rotating table 14 with vertical direction rotating function, and the lower rotating table 11 is connected to the support plate 6 through the base 7. The lower rotating table 11 is arranged below the upper rotating table 14, and a connecting seat 8 is arranged between the lower rotating table 11 and the upper rotating table 14. The lower rotating table 11 and the upper rotating table 14 are both driven to rotate by the servo motor 2. The servo motor 2 can drive the lower rotating table 11 and the upper rotating table 14 to rotate respectively through the existing worm and gear structure. The lower rotating table 11 drives the connecting seat 8 to rotate, and the connecting seat 8 drives the upper rotating table 14 to rotate in the rotating direction of the lower rotating table 11. The computer 1 is connected to the network interface of the servo motor 2 through a wired network to realize the free rotation of the lower rotating table 11 and the upper rotating table 14.

[0036] The heating and contact temperature measurement assembly includes an adjustable DC power supply 9, a ceramic heating sheet 5, a fiber reinforced composite prepreg strip sample 4, a thermocouple and a temperature tester 10. The adjustable DC power supply 9 is connected to the ceramic heating sheet 5 through wires as a temperature control device, and the ceramic heating sheet 5 is fixed on the upper rotating table 14 through spring clamps 13. The fiber reinforced composite prepreg strip sample 4 is arranged on the ceramic heating sheet 5, and the fiber reinforced composite prepreg strip sample 4 is pasted on the ceramic heating sheet 5 through high-temperature-resistant adhesive tape. The fiber reinforced composite prepreg strip sample 4 is provided with a thermocouple on the surface, and the thermocouple is connected to the temperature tester 10. The head end of the thermocouple is fixed on the surface of the fiber reinforced composite prepreg strip sample 4 through high-temperature-resistant adhesive tape and a flat clamp 12.

[0037] The method of the fiber reinforced composite material surface emissivity automatic testing device provided by the application comprises the following steps:

[0038] Step one, fixation and placement of the fiber reinforced composite material: the fiber reinforced composite prepreg strip sample 4 is pasted on the ceramic heating sheet 5 through high-temperature-resistant adhesive tape, the thermocouple is fixed on the surface of the fiber reinforced composite prepreg strip sample 4 through high-temperature-resistant IP adhesive tape and a flat clamp 12, and the flat clamp 12 is fixed to prevent slipping during the heating and rotating process. The head end of the flat clamp 12 is wrapped with PI adhesive tape in advance to prevent heat conduction from affecting the temperature measurement accuracy of the thermocouple. Then, the ceramic heating sheet 5 together with the fixed fiber reinforced composite prepreg strip sample 4 is placed in the spring clamps 13 on the upper rotating table 14.

[0039] Step two, each structure connection: adjustable DC power supply 9 is connected to ceramic heating sheet 5 through wires, thermocouple is connected to temperature tester 10, temperature tester 10 is connected to computer 1 through wired network, multi-degree-of-freedom rotating table is connected to computer 1 through wired network, infrared camera 3 is connected to computer 1 through wired network.

[0040] Step three, emissivity automatic measurement: pre-calibration of environmental parameters is carried out through computer 1, and calibration of infrared camera 3 lens is carried out, the environmental parameters include test distance, test environment temperature and humidity, and the test distance is the distance between the infrared camera and the sample. The position of the multi-degree-of-freedom rotating table or the infrared camera 3 is adjusted so that the observation area of the fiber reinforced composite prepreg strip sample 4 is located in the center of the imaging interface.

[0041] Infrared thermal imaging interface point temperature measurement of the fiber reinforced composite prepreg strip sample 4, the temperature measurement point is selected close to the actual temperature measurement point of the thermocouple. The voltage required for setting the target temperature is opened by the adjustable DC power supply 9, the temperature tester 10 is opened, and the actual temperature of the surface of the fiber reinforced composite prepreg strip sample 4 is recorded. After reaching the target temperature, the infrared camera 3 automatically starts adjusting the emissivity under the control of the computer 1, so that the temperature measured by the infrared camera 3 is consistent with the temperature measured by the temperature tester 10 connected with the thermocouple. At this time, the emissivity value of the infrared camera 3 is recorded as the actual emissivity of the fiber reinforced composite prepreg strip sample 4 at that temperature. For example, at a certain moment, the temperature tester 10 measures that the material is 100℃, and the infrared camera 3 automatically adjusts the emissivity value under the control of the computer 1 so that the infrared thermal imaging point temperature measurement temperature is equal to 100℃, at this time, the set emissivity value is regarded as the actual emissivity of the material at that temperature and is recorded.

[0042] Step four, adjusting the voltage to change the temperature to repeat the test process in step three to obtain the emissivity of the fiber reinforced composite prepreg strip sample 4 at different temperatures.

[0043] Step five, under the condition that the temperature does not change, the angle of the multi-degree-of-freedom rotating table is adjusted to obtain the emissivity of the fiber reinforced composite prepreg strip sample 4 at different angles.

[0044] By adjusting the rotation of the lower rotating table 11 of the multi-degree-of-freedom rotating table, the observation angle of the infrared camera 3 to the fiber reinforced composite prepreg strip sample 4 is changed. By adjusting the rotation of the upper rotating table 14 of the multi-degree-of-freedom rotating table, the orientation angle of the fiber reinforced composite prepreg strip sample 4 is changed.

[0045] At the same time, the temperature, the observation angle and the fiber orientation angle are changed, and through the above principle, the emissivity value of the fiber reinforced composite material under any condition can be obtained.

[0046] It should be pointed out finally that the above examples are only used to illustrate the technical solutions of the present application but not to limit it, and although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can still be modified or replaced equivalently, and these modifications or equivalent replacements should not make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. An automatic testing device for the surface emissivity of fiber-reinforced composite materials, characterized in that: The device includes a non-contact infrared temperature measurement component, a multi-degree-of-freedom rotary table, and a heating and contact temperature measurement component. The non-contact infrared temperature measurement component includes an infrared camera connected to a computer. The multi-degree-of-freedom rotary table is positioned in the direction of the infrared camera lens and includes a lower rotary table with horizontal rotation function and an upper rotary table with vertical rotation function. The heating and contact temperature measurement component includes an adjustable DC power supply and a temperature tester connected to a computer. The adjustable DC power supply is connected to a ceramic heating element, which is positioned on the upper rotary table. A fiber-reinforced composite prepreg sample is placed on the ceramic heating element, and a thermocouple is placed on the surface of the fiber-reinforced composite prepreg sample. The thermocouple is connected to the temperature tester.

2. The automatic emissivity testing device for fiber-reinforced composite materials according to claim 1, characterized in that: Both the infrared camera and the multi-degree-of-freedom rotary table are mounted on the support plate.

3. The automatic emissivity testing device for fiber-reinforced composite materials according to claim 1, characterized in that: The lower rotary table is located below the upper rotary table. Both the lower and upper rotary tables are driven to rotate by servo motors, which are connected to the computer.

4. The automatic emissivity testing device for fiber-reinforced composite materials according to claim 1, characterized in that: Spring clips are provided on the upper rotating platform, and the ceramic heating element is fixed to the upper rotating platform by the spring clips.

5. The automatic emissivity testing device for fiber-reinforced composite materials according to claim 1, characterized in that: The fiber-reinforced composite prepreg tape sample was placed on the ceramic heating plate using high-temperature resistant tape.

6. The automatic emissivity testing device for fiber-reinforced composite materials according to claim 1, characterized in that: The thermocouple was fixed to the surface of the fiber-reinforced composite prepreg sample using high-temperature resistant tape and a flat clamp.

7. The method for an automatic testing device for the surface emissivity of fiber-reinforced composite materials according to any one of claims 1-6, characterized in that: Includes the following steps: Step 1, Fixing and placing the fiber-reinforced composite material: Use high-temperature resistant tape to attach the fiber-reinforced composite prepreg tape sample to the ceramic heating plate, use high-temperature resistant tape to fix the thermocouple to the surface of the fiber-reinforced composite prepreg tape sample and fix it with a flat clamp, and then place the ceramic heating plate together with the fixed fiber-reinforced composite prepreg tape sample into the spring clamp on the upper rotating table. Step 2, connecting each structure: Connect the adjustable DC power supply to the ceramic heating element through wires, connect the thermocouple to the temperature tester, connect the temperature tester to the computer through a wired network, connect the multi-degree-of-freedom rotary table to the computer through a wired network, and connect the infrared camera to the computer through a wired network. Step 3, Automatic Emissivity Measurement: Environmental parameters are pre-calibrated using a computer, and the infrared camera lens is calibrated. The position of the multi-degree-of-freedom rotary stage or infrared camera is adjusted so that the observation area of ​​the fiber-reinforced composite prepreg sample is centered on the imaging interface. Temperature is measured at selected points on the infrared thermal imaging interface of the fiber-reinforced composite prepreg sample, choosing a measurement point close to the actual temperature measurement point of the thermocouple. The adjustable DC power supply is turned on to set the voltage required for the target temperature. The temperature tester is turned on, and the actual surface temperature of the fiber-reinforced composite prepreg sample is recorded. After the target temperature is reached, the infrared camera automatically starts adjusting its emissivity via the computer, ensuring that the infrared camera temperature measurement is consistent with the temperature measurement result of the temperature tester connected to the thermocouple. At this point, the emissivity value of the infrared camera is recorded as the actual emissivity of the fiber-reinforced composite prepreg sample at that temperature. Step four: Adjust the voltage and change the temperature, repeat the test process in step three to obtain the emissivity of fiber-reinforced composite prepreg tape samples at different temperatures; Step 5: Under constant temperature conditions, adjust the rotation angle of the multi-degree-of-freedom rotary table to obtain the emissivity of fiber-reinforced composite prepreg tape samples at different angles.

8. The method for an automatic testing device for the surface emissivity of fiber-reinforced composite materials according to claim 7, characterized in that: The flat-mouth clamp is pre-wrapped with high-temperature resistant tape.

9. The method for an automatic testing device for the surface emissivity of fiber-reinforced composite materials according to claim 7, characterized in that: In step three, environmental parameters include test distance and test environment temperature and humidity.

10. The method for an automatic testing device for the surface emissivity of fiber-reinforced composite materials according to claim 7, characterized in that: In step five, the observation angle of the fiber-reinforced composite prepreg tape sample is changed by adjusting the rotation of the lower rotary table of the multi-degree-of-freedom rotary table; the orientation angle of the fiber-reinforced composite prepreg tape sample is changed by adjusting the rotation of the upper rotary table of the multi-degree-of-freedom rotary table.

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