A multifunctional deformation measuring device and measuring method

Abstract

The invention relates to a multifunctional deformation measuring device and a measuring method, belonging to the technical field of thermal deformation measurement; the multifunctional deformation measuring device is manufactured; a test piece is marked; the accuracy of a measuring system is calibrated using a reference standard; a temperature sensor is installed on a test platform; a vacuum treatment is performed by a vacuum system; temperature is controlled by a temperature precision control module; a thermal radiation boundary is formed; the viewing angle and focal length of a measuring camera are adjusted; a monochromatic illumination light source is adjusted to achieve light coverage of the test piece; a speckle is sprayed on the test piece; an initial state of the test piece is measured; temperature is controlled by a temperature precision control module; and the deformation of the test piece at each temperature point during the entire test process is tested and recorded; the invention can solve the problems that the traditional method is limited to material-level samples in measuring test pieces, the applicable scope of measurement environment simulation is small, and the measurement error is large, so as to ensure high-precision measurement of thermal deformation of large-size composite material structures of spacecraft.

Description

Technical Field

[0001] The invention belongs to the technical field of thermal deformation measurement, and relates to a multifunctional deformation measurement device and a measurement method. Background Art

[0002] With the rapid development of high-precision and high-reliability spacecraft, high-stability structures represented by deployment arm rods, antenna rods, load reference structures, etc. are widely used in the development of high-precision and cutting-edge spacecraft products, which puts forward higher precision requirements for the thermal deformation measurement of their structures. Environmental simulation and accurate deformation measurement are crucial in the thermal deformation measurement of large-scale and high-stability structures. Traditional thermal deformation measurement methods mostly use a single ejector method or differential method, but the measurement environment of this measurement method is small and is only suitable for small-sized material-level specimens. There are great limitations on the application objects, and it is also difficult to meet the needs of high-precision measurement of thermal deformation of product-level structures. Summary of the invention

[0003] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art and propose a multifunctional deformation measurement device and measurement method, which can solve the difficulties of traditional methods in that the measurement specimens are limited to material-level samples, the measurement environment simulation has a small application range, and the measurement error is large, so as to ensure the high-precision measurement of thermal deformation of large-size composite material structures of spacecraft.

[0004] The solution of the present invention is:

[0005] A multifunctional deformation measuring device, comprising a high-stability camera supporting fixture, a fine push rod, a displacement sensor, a W-groove supporting frame, a loading device, a first acceleration sensor, a second acceleration sensor, a loading device fixing base, an air-floating vibration isolation supporting pier, a spring vibration isolation supporting system, a test platform, a fixing bracket, a reference standard, a fiber grating sensor, a test piece, a monochromatic illumination light source, a measuring camera, a data acquisition and processor, a data analysis and evaluation system, a brake, a demodulator and a signal processor, a temperature precision control module, an active / passive vibration isolation control system, a vacuum system and a thermal radiation boundary system;

[0006] Among them, the air-floating vibration isolation support pier is placed on the ground, and the top of the air-floating vibration isolation support pier supports the vacuum system; the thermal radiation boundary system is arranged in the inner cavity of the vacuum system; the thermal radiation boundary system controls the high and low temperature environment through the temperature precision control module; the test platform is placed inside the thermal radiation boundary system; the test platform adopts a spring vibration isolation support system for support and vibration isolation; the first acceleration sensor and the second acceleration sensor are pasted on the table and side of the test platform to realize vibration monitoring, and the table vibration is controlled through the active / passive vibration isolation control system; the fixed bracket is connected to the test platform with bolts, and the W-groove support frame is installed on the top of the fixed bracket, and the reference standard and the test piece are placed on the top of the W-groove support frame respectively; the fiber grating sensor is pasted on the surface of the reference standard and the test piece, and after passing through the cabin, it is connected with the demodulator and the signal The device is connected to a processor for deformation measurement; one end of the reference standard and the test piece on the same side is constrained by a fixed bracket, and the other end is connected to the loading device through a fine push rod; a displacement sensor is arranged on each fine push rod; the loading device is constrained by a fixed base of the loading device and fixed in the thermal radiation boundary system; the contact deformation measurement of the fine push rod is realized by the control of the brake; the high-stability camera support fixture is fixed above the vacuum high and low temperature environment simulation system, and the middle part of the high-stability camera support fixture constrains and fixes the monochromatic illumination light source; the two ends of the high-stability camera support fixture respectively constrain and fix the measuring camera; the measuring camera is connected to the data acquisition and processor to realize non-contact optical deformation measurement; the data acquisition and processor and the brake are connected to the data analysis and evaluation system to realize multifunctional deformation measurement.

[0007] The measuring method of the above-mentioned multifunctional deformation measuring device includes:

[0008] Before the test, mark the test piece;

[0009] Place a reference standard with a known thermal deformation coefficient in the measurement sample area and use the reference standard to calibrate the accuracy of the measurement system;

[0010] Install temperature sensors on the test platform, calibrate and debug the temperature sensors; evacuate the system through vacuum; control the temperature through the temperature precision control module; form a thermal radiation boundary;

[0011] Adjust the angle of view and focal length of the measuring camera to ensure that the measuring field of view covers the test area of ​​the test piece; adjust the monochromatic lighting source to ensure that the light covers the test piece;

[0012] Spraying speckles on the test piece;

[0013] Measure the initial state of the test piece;

[0014] Temperature control is performed through the temperature precision control module;

[0015] Test and record the deformation of the test piece at each temperature point during the entire test process; test the same test piece at least twice in a non-moving state; when the test piece is a composite pipe product, measure the same test piece in different quadrants at least 4 times.

[0016] In the above measurement method, the method for marking the test piece is:

[0017] When the surface of the test piece can be partially damaged, use a mechanical engraving knife or laser to carve permanent marking points on the surface of the test piece; when the surface of the test piece needs to remain intact, use spray or vacuum-resistant high and low temperature marker pen to draw marking points on the surface of the test piece; obtain the starting point or reference point of the measurement through the marking points.

[0018] In the above measurement method, the temperature sensors on the test platform are evenly arranged; the number of temperature sensors is not less than 4, and the accuracy of the temperature sensors is better than ±0.001°C.

[0019] In the above-mentioned measurement method, the preset vacuum degree P0 is achieved through the vacuum system; the temperature reaches the initial temperature T0 through the temperature precision control module; under the control of the temperature precision control module, the temperature fluctuation range of the thermal radiation boundary system is ±1°C.

[0020] In the above-mentioned measuring method, the contact force between the fine push rod and the tested piece is no more than 1N, and the fine push rod is kept tight in this state.

[0021] In the above measurement method, before spraying speckles on the tested piece, the test area is first determined, and white primer is sprayed evenly on the test area; after the white primer is dried, black speckle paint is used to spray speckles on the surface of the white primer; the speckles are evenly distributed.

[0022] In the above measurement method, multiple W-slot support frames are evenly distributed on the top of the fixed support; the distance between two adjacent W-slot support frames is not greater than 100 mm; after the test piece is installed on the W-slot support frame, the axis of the test piece is parallel to the horizontal line, and the parallelism is better than 0.01 mm / m; the distance between the reference standard and the test piece is 2-3 mm.

[0023] In the above-mentioned measurement method, the method for measuring the initial state of the test piece is:

[0024] Use a micrometer to measure the original length L0 of the test area of ​​the test piece; use an optical measuring camera to measure the initial test area of ​​the test piece, with a measurement accuracy of 0.1%.

[0025] In the above measurement method, the specific method of temperature control is:

[0026] The temperature is controlled at a heating rate of 0.5℃ / min to avoid uneven thermal stress; the measuring temperature points are set, and the temperature difference between adjacent measuring temperature points does not exceed 10℃. After rising to each temperature point, it is maintained for more than 30 minutes to make the temperature field in the cabin uniform before data collection.

[0027] The beneficial effects of the present invention compared with the prior art are:

[0028] (1) The present invention provides a vacuum high and low temperature environment for thermal deformation measurement through a space environment simulation module, provides a stable bottom support function for the entire vibration control system through an active and passive air flotation vibration isolation system, and circulates the medium on the inner wall of the vacuum container through a thermal radiation boundary system to form a uniform vacuum high and low temperature environment, thereby reducing the impact of temperature changes on the environmental temperature control accuracy;

[0029] (2) The present invention uses a non-contact optical measurement module, a high-precision industrial camera and an image analysis algorithm to measure the thermal deformation of the test piece; uses a fiber grating measurement module to arrange a fiber grating sensor on the surface of the test piece to measure the linear thermal deformation of the test piece; uses a push rod contact measurement module to contact the end face of the sample to be tested with a fine push rod assembly, records the push rod displacement, and measures the linear thermal deformation of the test piece;

[0030] (3) The present invention proposes a non-contact high-precision method for measuring thermal deformation, which can work stably in extremely high and low temperature environments. The measuring light beam can effectively eliminate the hot air disturbance and thermal lens effect outside the observation window. It has multiple advantages such as non-destructive, high precision, wide adaptability, high stability, high repeatability, small system error, and real-time data processing, and realizes accurate measurement of thermal deformation in extreme environments.

[0031] (4) The present invention ultimately solves the problems of traditional methods in that the measurement specimens are limited to material-level samples, soft or fragile structures cannot be measured, and contact measurement causes mechanical stress or heat conduction that affects the measurement accuracy through a thermal deformation measurement method based on an optical-fiber-rod multi-method combination. This method realizes the thermal deformation measurement of large-scale, high-stability composite materials structures at the product level, such as deployment arm rods, antenna rods, and load reference structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the multifunctional deformation measuring device of the present invention;

[0033] Figure 2 It is a schematic diagram of the installation of the tested object and the reference standard of the present invention;

[0034] Figure 3 It is a schematic diagram of the W-shaped groove bracket of the present invention. DETAILED DESCRIPTION

[0035] The present invention will be further described below in conjunction with the embodiments.

[0036] The present invention provides a multifunctional deformation measurement device and method, which can solve the problems of traditional methods such as the measurement specimens are limited to material-level samples, the measurement environment simulation has a small application range, and the measurement error is large, so as to ensure the high-precision measurement of thermal deformation of large-size composite material structures of spacecraft.

[0037] Make a multifunctional deformation measurement device, such as Figure 1 As shown, it specifically includes a high-stability camera supporting tooling 1, a fine push rod 2, a displacement sensor 3, a W-shaped groove supporting frame 4, a loading device 5, a first acceleration sensor 6, a second acceleration sensor 7, a loading device fixed base 8, an air-floating vibration isolation supporting pier 9, a spring vibration isolation supporting system 10, a test platform 11, a fixed bracket 12, a reference standard 13, a fiber grating sensor 14, a test piece 15, a monochromatic lighting source 16, a measuring camera 17, a data acquisition and processor 18, a data analysis and evaluation system 19, a brake 20, a demodulator and a signal processor 21, a temperature precision control module 22, an active / passive vibration isolation control system 23, a vacuum system 24 and a thermal radiation boundary system 25.

[0038] Among them, the air-floating vibration isolation support pier 9 is placed on the ground, and the top of the air-floating vibration isolation support pier 9 supports the vacuum system 24; the thermal radiation boundary system 25 is arranged in the inner cavity of the vacuum system 24; the thermal radiation boundary system 25 controls the high and low temperature environment through the temperature precision control module 22; the test platform 11 is placed inside the thermal radiation boundary system 25; the test platform 11 adopts the spring vibration isolation support system 10 for support and vibration isolation; the first acceleration sensor 6 and the second acceleration sensor 7 are pasted on the table and side of the test platform 11 to realize vibration monitoring, and the table vibration is controlled by the active / passive vibration isolation control system 23; the fixed bracket 12 is connected to the test platform 11 by bolts, the W-groove support frame 4 is installed on the top of the fixed bracket 12, and the reference standard 13 and the test piece 15 are placed on the top of the W-groove support frame 4 respectively; the fiber grating sensor 14 is pasted on the surface of the reference standard 13 and the test piece 15, and after penetrating the cabin, it is connected with the solution. The regulator is connected to the signal processor 21 for deformation measurement; the reference standard 13 and the test piece 15 are constrained on one end on the same side by the fixed bracket 12, and the other end is connected to the loading device 5 through a fine push rod 2; a displacement sensor 3 is arranged on each fine push rod 2; the loading device 5 is constrained by the loading device fixed base 8 and fixed in the thermal radiation boundary system 25; the contact deformation measurement of the fine push rod 2 is realized by the control of the brake 20; the high-stability camera support fixture 1 is fixed above the vacuum high and low temperature environment simulation system, and the middle part of the high-stability camera support fixture 1 constrains and fixes the monochromatic illumination light source 16; the two ends of the high-stability camera support fixture 1 respectively constrain and fix the measuring camera 17; the measuring camera 17 is connected to the data acquisition and processor 18 to realize non-contact optical deformation measurement; the data acquisition and processor 18 and the brake 20 are both connected to the data analysis and evaluation system 19 to realize multifunctional deformation measurement.

[0039] In the present invention, the contact force between the fine push rod 2 and the tested piece 15 is no more than 1N, and the fine push rod 2 is kept tight in this state.

[0040] Multiple W-groove support frames 4 are evenly distributed on the top of the fixed bracket 12; the distance between two adjacent W-groove support frames 4 is not greater than 100 mm; after the test piece 15 is installed on the W-groove support frame 4, the axis of the test piece 15 is parallel to the horizontal line, and the parallelism is better than 0.01 mm / m; the distance between the reference standard 13 and the test piece 15 is 2-3 mm.

[0041] The multifunctional deformation measurement method specifically comprises the following steps:

[0042] Before the test, the test piece 15 is marked. The method for marking the test piece 15 is:

[0043] When the surface of the test piece 15 can be partially damaged, a mechanical engraving knife or laser is used to engrave a permanent marking point on the surface of the test piece 15; when the surface of the test piece 15 needs to keep intact, a spray or vacuum-resistant high and low temperature marking pen is used to draw marking points on the surface of the test piece 15; the starting point or reference point of the measurement is obtained through the marking point.

[0044] A reference standard 13 with a known thermal deformation coefficient is placed in the measurement sample area, and the accuracy of the measurement system is calibrated using the reference standard 13 .

[0045] A temperature sensor is installed on the test platform 11, and the temperature sensor is calibrated and debugged; a vacuum process is performed through the vacuum system 24; the temperature is controlled through the temperature precision control module 22; and a thermal radiation boundary is formed.

[0046] The temperature sensors on the test platform 11 are evenly arranged; the number of temperature sensors is not less than 4, and the accuracy of the temperature sensors is better than ±0.001°C.

[0047] The preset vacuum degree P0 is achieved through the vacuum system 24; the temperature reaches the initial temperature T0 through the temperature precision control module 22; under the control of the temperature precision control module 22, the temperature fluctuation range of the thermal radiation boundary system 25 is ±1°C.

[0048] The viewing angle and focal length of the measuring camera 17 are adjusted to achieve that the measuring field of view covers the test area of ​​the test piece 15 ; and the monochromatic illumination light source 16 is adjusted to achieve that the light covers the test piece 15 .

[0049] Spraying speckles on the test piece 15. Before spraying speckles on the test piece 15, first determine the test area, and spray white primer evenly on the test area; after the white primer is dry, use black speckle paint to spray speckles on the surface of the white primer; the speckles are evenly distributed.

[0050] The initial state of the test piece 15 is measured.

[0051] The method for measuring the initial state of the test piece 15 is:

[0052] The original length L0 of the test area of ​​the test piece 15 is measured using a micrometer; the initial test area of ​​the test piece 15 is measured using an optical measuring camera, with a measurement accuracy of 0.1%.

[0053] The temperature is controlled by the temperature precision control module 22. The specific method of temperature control is:

[0054] The temperature is controlled at a heating rate of 0.5℃ / min to avoid uneven thermal stress; the measuring temperature points are set, and the temperature difference between adjacent measuring temperature points does not exceed 10℃. After rising to each temperature point, it is maintained for more than 30 minutes to make the temperature field in the cabin uniform before data collection.

[0055] The deformation of the test piece 15 at each temperature point during the entire test process is tested and recorded.

[0056] The same test piece 15 shall be tested at least twice in a non-moving state; when the test piece 15 is a composite pipe product, the same test piece 15 shall be measured at least 4 times in different quadrants.

[0057] Example

[0058] Step 1: Preparation of the test piece 15. The test piece 15 is selected or processed according to the test requirements.

[0059] The size, shape and quality of the test piece 15 must meet the test requirements. Special test pieces should be pre-processed according to a specific processing flow to eliminate variables that may be introduced by previous historical properties or environmental factors to ensure that the sample reaches the state required for the test. In addition, it is necessary to ensure that the surface of the test piece is clean and free of oil stains and impurities to avoid affecting the measurement effect.

[0060] Step 2: Marking of the test piece 15. Before the test, the test area is marked on the sample surface.

[0061] Among them, for samples that can be partially damaged on the surface, a mechanical engraving knife or laser can be used to make a permanent mark on the surface of the test piece 15; for the test piece 15 that cannot be directly scratched on the sample, spray or a marker pen that is resistant to vacuum and high and low temperatures can be used to draw marks or points on the surface of the test piece 15 to obtain the starting point or reference point of the measurement.

[0062] Step 3: Preparation of reference standard 13. Place a reference standard 13 with known thermal deformation in the measurement sample area, and use the reference standard 13 to calibrate the accuracy of the measurement system.

[0063] The reference standard 13 should be prepared according to different known thermal deformation coefficient magnitudes, and the reference standard 13 should have excellent thermal stability to ensure that its thermal deformation properties remain consistent during multiple or long-term tests.

[0064] Step 4: Installation and debugging of space environment simulation module. Install and arrange temperature sensors on the test platform 11, connect them to the corresponding temperature acquisition modules, and calibrate and debug the temperature sensors. Control the vacuum pumping device through the vacuum system 24 to evacuate the cabin to the required vacuum degree P. The temperature field in the vacuum cabin is made to reach the initial T0 through the temperature precision control module 22, and the temperature fluctuation range is allowed to be ±1°C, forming a thermal radiation boundary.

[0065] The temperature sensors of the test platform 11 should be evenly arranged, with no less than 4 sensors, and the accuracy of the temperature sensors should be better than ±0.001°C. The inner wall of the vacuum chamber is a sandwich structure, with medium circulation pipelines evenly arranged in the middle. The pipelines have high and low temperature resistance, and the circulating medium is input from an external tank.

[0066] The test platform 11 is placed on the spring vibration isolation support system 10 to ensure the stability of the test platform.

[0067] The space environment simulation module is placed as a whole on the air-floating vibration isolation support pier 9, and the full-frequency domain micro-vibration control of the space environment simulation module is achieved through the active / passive vibration isolation control system 23.

[0068] Step 5: Install and adjust the ejector contact thermal deformation measurement system.

[0069] 1) Installation and adjustment of the top rod measuring system

[0070] The W-groove support frame 4 is installed on the test platform 11 , the loading device 5 is installed on the end of the support frame, and the displacement sensor 3 is connected to the loading device 5 .

[0071] 2) Installation of the test piece 15 and the reference standard 13

[0072] Install the test piece 15 and the reference standard 13 on the W-groove support frame 4, touch one end of the fine push rod 2 assembly with the end face of the test piece 15, and touch one end of the reference push rod with the end face of the reference standard 13. The contact force between the push rod and the test piece 15 is not greater than 1N. At the same time, ensure that the sample remains tight in this state. Ensure that the mechanical connection is stable and reliable during the entire measurement process. The other end passes through the displacement sensor 3 and is connected to the loading device 5. The installation state is as follows Figure 2 shown.

[0073] Step 6: Non-contact optical measurement system installation and adjustment. Specific:

[0074] 1) Installation of non-contact optical measurement system

[0075] Install the non-contact optical measurement unit measurement camera 17 onto the system measurement baseline rod, and adjust its viewing angle and focal length to ensure that the measurement field of view can fully cover the measured area of ​​the sample to be tested, and then install the monochromatic illumination light source 16 directly above the non-contact optical measurement unit so that the measurement light can completely cover the test piece 15.

[0076] The non-contact optical measurement unit usually uses two or more CCD cameras to collect speckle or marker point images of the test piece 15 at various deformation stages in real time.

[0077] The monochromatic illumination light source 16 should be selected with stable light intensity and good uniformity, and can eliminate the interference of ambient light to reduce errors.

[0078] 2) The test piece 15 is sprayed with speckle.

[0079] First, determine the measurement area and spray white primer evenly on the measurement area. After the white primer is dry, use black speckle paint to spray speckle on the surface of the white primer in the measurement area. The speckle should be as uniform as possible to avoid the speckle being too large.

[0080] Among them, the spraying of white primer should be based on the color of the test piece's surface completely, and it should not be sprayed unevenly or too thickly.

[0081] 3) The test piece 15 is installed.

[0082] Fix the test piece 15 on the W-groove support frame 4 on the test platform 11 as required, and use the push rod device to lightly touch the end face of the test piece 15. The sample installation must ensure that the sample will not undergo rigid displacement changes due to heating or cooling during the test, thereby affecting the test results.

[0083] It is recommended that the tested object 15 be fixed by using multiple W-shaped groove support frames 4 of the same size. Figure 3 All tooling brackets are made of the same material and process.

[0084] To avoid the deflection of the test piece during the test, the distance between the test piece support fixtures should be no greater than 100mm. The flatness of the test piece fixed support surface should be better than 0.02mm.

[0085] After the specimen is fixed, the axis direction should be parallel to the horizontal line, and the collinearity should be better than 0.01mm / m.

[0086] The reference standard 13 is placed near the tested specimen, with the distance range being kept within 2 mm to 3 mm.

[0087] 4) System calibration

[0088] Select a calibration plate of appropriate size according to the size of the measurement field of view, place the calibration plate in the camera field of view area, and perform calibration. During the calibration process, the calibration plate needs to be translated or rotated so that the entire market can be calibrated. After the calibration is completed, check the camera calibration results. If it meets the measurement requirements, the calibration is completed. Otherwise, recalibration is required.

[0089] Step 7: Install and adjust the optical fiber displacement measurement system.

[0090] 1) Sensor detection and debugging

[0091] The fiber grating sensor 14 is connected to a demodulator to detect whether there is a wavelength output.

[0092] 2) The sensor is placed on the sample to be tested

[0093] The tested piece 15 is mounted on the W-groove support frame 4, and the fiber grating sensor 14 is arranged on the product. The arrangement forms include: ① directly fixing it to the surface of the tested sample by clamps at both ends or welding; ② for samples that are not easy to directly contact or cannot be destroyed, fix it to the surface of the sample by bundling or gluing.

[0094] Step 8: Test preparation. Measure the initial state of the test piece 15, the method is as follows: ① Use a micrometer to measure the original length L0 of the test area; ② Use an optical measurement camera to measure the initial test area of ​​the test sample, and the measurement accuracy is accurate to 0.1%.

[0095] Step 9: System joint debugging. Turn on the non-contact optical measurement module, fiber Bragg grating measurement module, and push rod contact measurement module at the same time, and conduct joint debugging of the measurement field of view, measurement program, measurement area, parameter settings, etc. of the entire system. The specific method is as follows:

[0096] 1) Use the system to measure the initial state of the test piece 15 at normal temperature and pressure, perform a solution, and compare the solution result with the initial length L0 to verify the measurement accuracy of the system.

[0097] 2) Use the ejector loading system to apply a certain load to the test sample, and use the system to collect and solve the deformation of the test sample to verify the reliability of the system.

[0098] Step 9: Start the environmental simulation equipment. Start the vacuum high and low temperature environment control program according to the set parameters. The temperature is controlled at a heating rate of 0.5℃ / min to avoid uneven thermal stress. The heating interval does not exceed 10℃. After reaching each temperature point, keep it for at least 30 minutes to make the temperature field in the cabin relatively uniform before data collection.

[0099] During the test, the temperature uniformity in the target area is monitored throughout the entire area, and the control system is promptly fed back and fine-tuned for large temperature fluctuations or abnormal temperature rise and fall phenomena.

[0100] Step 10: Data collection and analysis: Use a high-precision thermal deformation measurement system that combines multiple methods to continuously record the deformation of the sample at each temperature point T1, T2, etc. during the entire test process.

[0101] The same test sample shall be measured at least twice without moving the test sample, and the number of test samples of the same test sample shall not be less than 2.

[0102] For composite pipes, at least 4 measurements are performed on the same test sample in different quadrants.

[0103] The present invention proposes a non-contact high-precision method for measuring thermal deformation, which can work stably in extremely high and low temperature environments. The measuring light beam can effectively eliminate the hot air disturbance and thermal lens effect outside the observation window. It has multiple advantages such as non-destructive, high precision, wide adaptability, high stability, high repeatability, small system error, and real-time data processing, and realizes the accurate measurement of thermal deformation in extreme environments.

[0104] The present invention proposes a high-precision thermal deformation measurement method for large-scale product-level composite materials based on the combination of optical-fiber-rod multiple methods. The method can solve the problems of traditional methods in which the measurement specimens are limited to material-level samples, soft or fragile structures cannot be measured, and contact measurement causes mechanical stress or heat conduction that affects the measurement accuracy. The method realizes the thermal deformation measurement of large-scale, high-stability composite materials such as deployment arm rods, antenna rods, and load reference structures.

[0105] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A multifunctional deformation measuring device, characterized in that: It includes a camera support fixture (1), a push rod (2), a displacement sensor (3), a W-shaped groove support frame (4), a loading device (5), a first acceleration sensor (6), a second acceleration sensor (7), a loading device fixed base (8), an air-floating vibration isolation support pier (9), a spring vibration isolation support system (10), a test platform (11), a fixed bracket (12), a reference standard (13), a fiber grating sensor (14), a test piece (15), a monochromatic illumination source (16), a measuring camera (17), a data acquisition and processor (18), a data analysis and evaluation system (19), a brake (20), a demodulator and a signal processor (21), a temperature precision control module (22), an active / passive vibration isolation control system (23), a vacuum system (24) and a thermal radiation boundary system (25); The air-floating vibration isolation support pier (9) is placed on the ground, and the top of the air-floating vibration isolation support pier (9) supports the vacuum system (24); the thermal radiation boundary system (25) is arranged in the inner cavity of the vacuum system (24); the thermal radiation boundary system (25) controls the high and low temperature environment through the temperature precision control module (22); the test platform (11) is placed inside the thermal radiation boundary system (25); the test platform (11) is supported and isolated by the spring vibration isolation support system (10); the first acceleration sensor (6) and the second acceleration sensor (7) are attached to the table top and side of the test platform (11) to realize vibration monitoring, and the table body vibration is controlled by the active / passive vibration isolation control system (23); the fixed bracket (12) and the test platform (11) are connected by bolts, the W-shaped groove support frame (4) is installed on the top of the fixed bracket (12), and the reference standard (13) and the test piece (15) are placed on the top of the W-shaped groove support frame (4); the fiber grating sensor ( 14), after penetrating the cabin, it is connected to a demodulator and a signal processor (21) for deformation measurement; one end of the reference standard (13) and the test piece (15) on the same side is constrained by a fixed bracket (12), and the other end is connected to a loading device (5) through a push rod (2); a displacement sensor (3) is set on each push rod (2); the loading device (5) is constrained by a loading device fixed base (8) and fixed in the thermal radiation boundary system (25); the push rod (2) is controlled by a brake (20) to achieve contact The invention relates to a method for realizing non-contact optical deformation measurement; a camera support fixture (1) is fixed above a vacuum high and low temperature environment simulation system, and a monochromatic illumination light source (16) is constrained and fixed in the middle of the camera support fixture (1); a measuring camera (17) is constrained and fixed at both ends of the camera support fixture (1); the measuring camera (17) is connected to a data acquisition and processor (18) to realize non-contact optical deformation measurement; the data acquisition and processor (18) and the brake (20) are both connected to a data analysis and evaluation system (19) to realize multifunctional deformation measurement.

2. The measuring method of the multifunctional deformation measuring device according to claim 1, characterized in that: include: Before the test, the test piece (15) is marked; Placing a reference standard (13) with a known thermal deformation coefficient in a measurement sample area, and using the reference standard (13) to calibrate the accuracy of the measurement system; A temperature sensor is installed on the test platform (11), and the temperature sensor is calibrated and debugged; a vacuum process is performed through a vacuum system (24); temperature is controlled through a temperature precision control module (22); and a thermal radiation boundary is formed; Adjusting the viewing angle and focal length of the measuring camera (17) to achieve that the measuring field of view covers the test area of ​​the test piece (15); adjusting the monochromatic illumination light source (16) to achieve that the light covers the test piece (15); Spraying speckles on the test piece (15); Measuring the initial state of the test piece (15); Temperature control is performed through a temperature precision control module (22); The deformation of the test piece (15) at each temperature point during the entire test process is tested and recorded; the same test piece (15) is tested at least twice in a non-moving state; when the test piece (15) is a composite pipe product, the same test piece (15) is measured at different quadrants at least four times.

3. The measuring method according to claim 2, characterized in that: The method for marking the test piece (15) is as follows: When the surface of the test piece (15) can be partially damaged, a mechanical engraving knife or a laser is used to engrave a permanent marking point on the surface of the test piece (15); when the surface of the test piece (15) needs to be kept intact, a spray or vacuum-resistant high and low temperature marking pen is used to draw a marking point on the surface of the test piece (15); and a starting point or a reference point for measurement is obtained through the marking point.

4. The measuring method according to claim 2, characterized in that: The temperature sensors on the test platform (11) are evenly arranged; the number of temperature sensors is not less than 4, and the accuracy of the temperature sensors is better than ±0.001°C.

5. The measuring method according to claim 4, characterized in that: A preset vacuum degree P0 is achieved through the vacuum system (24); the temperature reaches an initial temperature T0 through the temperature precision control module (22); and under the control of the temperature precision control module (22), the temperature fluctuation range of the thermal radiation boundary system (25) is ±1°C.

6. The measuring method according to claim 2, characterized in that: The contact force between the push rod (2) and the tested piece (15) is no greater than 1N, and the push rod (2) remains tight in this state.

7. The measuring method according to claim 2, characterized in that: Before spraying speckles on the tested piece (15), a test area is first determined, and white primer is evenly sprayed on the test area; after the white primer is dry, black speckle paint is used to spray speckles on the surface of the white primer; the speckles are evenly distributed.

8. The measuring method according to claim 2, characterized in that: A plurality of W-shaped groove support frames (4) are evenly distributed on the top of the fixed support (12); the distance between two adjacent W-shaped groove support frames (4) is no greater than 100 mm; after the test piece (15) is mounted on the W-shaped groove support frame (4), the axis of the test piece (15) is parallel to the horizontal line, and the parallelism is better than 0.01 mm / m; and the distance between the reference standard (13) and the test piece (15) is 2-3 mm.

9. The measuring method according to claim 2, characterized in that: The method for measuring the initial state of the test piece (15) is: The original length L0 of the test area of ​​the test piece (15) is measured using a micrometer; the initial test area of ​​the test piece (15) is measured using an optical measuring camera, with a measurement accuracy of 0.1%.

10. The measuring method according to claim 2, characterized in that: The specific method of temperature control is: The temperature is controlled at a heating rate of 0.5℃ / min to avoid uneven thermal stress; the measuring temperature points are set, and the temperature difference between adjacent measuring temperature points does not exceed 10℃. After rising to each temperature point, it is maintained for more than 30 minutes to make the temperature field in the cabin uniform before data collection.

Images