Thermal intensity test system and method for realizing large-area ultrahigh-temperature heating by splicing multiple laser beams

Abstract

The invention provides a thermal intensity test system and method for realizing large-area ultrahigh-temperature heating by splicing multiple laser beams. The system comprises a computer, a controller, a laser, a power meter, an optical fiber, an output head, a bracket, an adjustable platform, a heat flow meter and a data collector. Wherein an angle adjusting device is designed on the output head, so that the laser irradiation angle can be finely adjusted, and then the position of a light spot can be finely adjusted; and an optical focusing device is designed on the output head, so that equal-proportion amplification and reduction of light spots can be realized in a focusing manner, and the distance between the laser head and a heated surface is not changed. The device can be customized according to the requirement of the aerospace craft structure thermal test, and the application problem of laser heating in the aerospace craft structure thermal test is solved.

Description

Technical Field

[0001] The present invention belongs to the field of thermal testing of aerospace vehicle structures, and in particular relates to a thermal strength testing system and method for realizing large-area ultra-high temperature heating by splicing multiple laser beams. Background Art

[0002] Aerospace vehicles face severe aerodynamic heating problems when flying at high speed in the atmosphere. It is necessary to conduct structural thermal tests on the aircraft structure on the ground to assess its comprehensive performance such as heat insulation, heat resistance, and high-temperature bearing. At present, in the aircraft structure thermal test, the means of heating the test piece mainly include radiation methods such as quartz lamps, graphite, and arc lamps. However, the heating capacity of quartz lamps is generally low. The heating capacity of graphite is higher than that of quartz lamps, but the thermal inertia is large, and graphite materials have obvious oxidation problems at high temperatures, and the high-temperature heating capacity is limited. Arc lamps are inconvenient to use, and their application scale is limited. In recent years, with the increasing flight Mach number of aircraft, the aerodynamic heating faced by aircraft structures has become more serious, the heating temperature requirements have become higher and higher, and the heating area has gradually tended to the entire aircraft structure, which obviously exceeds the existing test technology capabilities. Therefore, the development of a new large-area high-temperature heating technology for aircraft structures is of great significance to model development.

[0003] The essence of laser heating is to use laser to irradiate the surface of the material, so that the material absorbs the light energy and converts it into heat energy, thereby achieving the purpose of increasing the temperature. The most notable features of laser heating are "directional, local, and high energy", which has significant advantages over conventional heating methods such as quartz lamps and graphite. Therefore, applying laser heating technology to thermal testing of aerospace vehicle structures is an effective way to improve the existing test heating capabilities.

[0004] At present, high-energy lasers are widely used in laser ablation, welding, cutting, etc. However, relative to the strength test of aircraft structures at high temperatures, not only high energy is required, but also large-area, controllable, and uniform heating is required on the surface of the structure to generate high temperature, and other mechanical loads are applied in combination to assess its comprehensive strength and other properties at high temperatures. The laser spot concentrated at one "point" needs to be diffused and shaped, and multiple laser beams need to be spliced ​​to achieve extremely high-temperature heating over a large area. These problems all require technical research and solutions.

[0005] In summary, the existing technology uses laser heating in the thermal strength test of aircraft structures, and the problems that need to be solved include:

[0006] 1) Existing laser systems in the industrial field are not applicable to structural thermal testing, and overall system design and customization are required;

[0007] 2) In the structural thermal test, the shape and size of the heated area of ​​the heated object are not constant, and it is necessary to establish a multi-beam laser splicing method to achieve large-area heating;

[0008] 3) Lasers are generally invisible light and cannot be seen directly by human eyes, which makes it impossible to align the laser-heated parts and confirm whether the heated parts meet the test requirements. Therefore, it is necessary to solve the laser alignment problem;

[0009] 4) Lasers are generally collimated beams, and the farther the distance, the larger the spot. When a larger spot is required, the heating distance is larger, which causes the problem of insufficient space in structural thermal tests. The distance adjustment problem of laser heating needs to be solved;

[0010] 5) The heat flux load applied to the test piece in the structural thermal test must be quantifiable and controllable. A reasonable heating test process needs to be formulated to ensure that the heat flux load application meets the test requirements. Summary of the invention

[0011] The purpose of the present invention is to solve the problems existing in the above-mentioned prior art and to provide a thermal strength test system and method for realizing large-area ultra-high temperature heating by splicing multiple laser beams.

[0012] The present invention provides a thermal strength test system for realizing large-area ultra-high temperature heating by splicing multiple laser beams. The system comprises: a computer, a controller, a laser, a power meter, an optical fiber, an output head, a bracket, an adjustable platform, a heat flux meter, and a data collector.

[0013] The role of the computer is to set and monitor the laser power and heat flux density, control the emission and shutdown of the laser and indicator light, etc.

[0014] The function of the controller is to transform the control signal sent by the computer and transmit it to the laser.

[0015] The function of the laser is to convert external electrical energy into laser or indicator light. Multiple laser beams correspond to multiple lasers.

[0016] The function of the power meter is to monitor the laser power emitted by the laser in real time. Multiple laser beams correspond to multiple power meters.

[0017] The function of optical fiber is to transmit laser. Multiple laser beams correspond to multiple optical fibers.

[0018] The function of the output head is to emit the laser transmitted by the optical fiber after optical transformation. Multiple laser beams correspond to multiple output heads.

[0019] The function of the bracket is to install and fix the output head. One bracket can install a group of output heads to emit multiple laser beams.

[0020] The adjustable platform serves to mount the fixed bracket.

[0021] The function of the heat flux meter is to measure the heat flux density value of the laser spot and solve the problem of quantitative application of the heat flux load of laser heating to ensure that the accuracy of heat flux load application meets the test requirements.

[0022] The function of the data logger is to collect the heat flux density value of the heat flow meter and transmit it to the computer.

[0023] The present invention provides a thermal strength test method for realizing large-area ultra-high temperature heating by splicing multiple laser beams, comprising the following steps: large-area heating customization, laser alignment, heating distance adjustment, and heating test. The specific method steps are as follows.

[0024] A. Customized method for large area heating

[0025] The multi-beam laser splicing method is used to achieve large-area heating customization. The specific method is:

[0026] 1) First, the spot shape of a single laser beam is designed to be square or rectangular, and the energy distribution inside the spot is ensured to be uniform.

[0027] 2) Second, multiple square or rectangular light spots are spliced ​​and combined. Splice into the entire heating surface according to the shape of the heated surface. The specific splicing and combination method is: multiple output head mounting holes are designed on the bracket. Multiple output heads are installed on the bracket. When multiple output heads emit multiple laser beams at the same time, multiple laser spots will present a light spot heating array according to the relative installation positions. The relative positions of the mounting holes on the bracket are designed according to the shape of the heated surface of the test piece, so the shape of the light spot heating array is the shape of the heated surface.

[0028] 3) Thirdly, in order to solve the boundary connection problem between the light spots in the light spot heating array, an angle adjustment device is designed on the output head to fine-tune the angle of laser irradiation, and then fine-tune the position of the light spot to avoid too much overlap or too large spacing between the light spots, thereby improving the energy uniformity inside the light spot heating array.

[0029] Through the above three steps, multiple laser beams can be used to form a spot heating array, which can be spliced ​​into the required heating area, and the overlap quality of the spots inside the spot heating array and the spot boundaries is guaranteed, thereby achieving the purpose of heating area customization.

[0030] B. Laser alignment method

[0031] After using multiple laser beams to form a spot heating array, the position of the entire spot heating array needs to be adjusted so that it faces and covers the heated surface. The specific laser alignment method is:

[0032] 1) First, multiple output heads are mounted on a bracket, and the bracket is mounted and fixed on an adjustable platform. The adjustable platform is designed with three-way translation and three-axis rotation position adjustment functions, which can realize the overall three-way translation and three-axis rotation of the spot heating array, and then align and cover the heated surface.

[0033] 2) Secondly, the laser is designed to emit both laser and indicator light. Laser is emitted during the formal test. In the laser alignment process, indicator light is emitted. The indicator light is visible light (can be red light) and is harmless to the human eye. The size and shape of the indicator light spot are exactly the same as those of the formal laser, which can intuitively display the position, area, size, etc. of the light spot heating array, making laser alignment easier to operate.

[0034] C. Heating distance adjustment method

[0035] The output head is designed with an optical focusing device, which can achieve proportional enlargement and reduction of the light spot by focusing, without changing the distance between the laser head and the heated surface (i.e., the heating distance).

[0036] D. Heating test process

[0037] 1) The first step is heating and debugging test: set the laser power through the computer, and the laser emits laser light to the heat flux meter, and the heat flux density value is obtained by the heat flux meter test. Adjust the laser power set by the computer so that the heat flux density value is equal to the heat flux density value required by the test, and then record the set laser power. If multiple heat flux density values ​​are involved, repeat the above work and test them one by one.

[0038] 2) The second step is the formal test: remove the heat flux meter and install the formal test piece in the same position. After adjusting the spot position, start heating according to the laser power recorded in the first step as the set value, and then start the formal heating test until the end of the test.

[0039] The beneficial effects of the present invention are as follows:

[0040] 1. The present invention provides a general system solution of multi-beam laser joint heating according to the unique requirements of aerospace aircraft structure thermal test, and provides the system composition and function. Its beneficial effects are: the general system solution is customized according to the requirements of aerospace aircraft structure thermal test, and solves the application problem of laser heating in aerospace aircraft structure thermal test;

[0041] 2. The present invention provides a method for customizing the heating area. The laser spot shape is designed to be square or rectangular, and the energy distribution inside the spot is ensured to be uniform. Multiple output heads are installed on a bracket, and the bracket is designed with multiple mounting holes. The relative position distribution of the mounting holes is designed in a simulated manner according to the shape of the heated surface of the test piece. An angle adjustment device is designed on the output head.

[0042] The beneficial effects are as follows: the light spot shape is square or rectangular, which is more conducive to the boundary processing when the light spots are spliced. The energy distribution inside the light spot is uniform, which meets the requirements for the uniformity of the heating thermal field in the test. Multiple output heads are installed on the bracket, and the relative position distribution of the mounting holes is designed according to the shape of the heated surface of the test piece. Multiple laser beams can be spliced ​​and combined into a light spot heating array according to the shape and size of the heated surface. An angle adjustment device is designed on the output head to fine-tune the angle of laser irradiation, thereby solving the problem of splicing between the light spots inside the light spot heating array. In summary, the customization problems of the size and shape of the heating area during laser heating can be solved.

[0043] 3. The present invention provides a laser alignment method. The bracket is mounted and fixed on an adjustable platform. The adjustable platform has a six-dimensional (displacement, angle) position adjustment function. The laser can emit visible indicator light, and the size and shape of the indicator spot are exactly the same as those of the regular laser.

[0044] The beneficial effects are as follows: the position adjustment function of the adjustable platform can realize the overall position adjustment of the spot heating array, and finally face and cover the heated part. The indicator light can be emitted to intuitively display the laser heating area and shape, and the position of the laser irradiation can be adjusted with the adjustment device, and then the heating part can be adjusted and confirmed to ensure that the heating part meets the test requirements. In summary, the problem of laser alignment can be solved.

[0045] 4. The present invention provides a solution to the laser heating distance. An optical focusing device is designed on the output head, which can achieve proportional enlargement and reduction of the light spot through focusing and ensure the uniformity of the laser.

[0046] The beneficial effects are: the light spot can be enlarged and reduced in proportion by focusing, so that the laser heater has the function of customizing the light spot size according to the shape and area of ​​the heated surface without moving the test piece, thus overcoming the problem of heating distance of collimated laser heating.

[0047] 5. The present invention provides a heating test process. The first step is heating scheme design: the heating scheme design is carried out according to the shape, size and heating heat flux density of the heated surface, and the bracket is designed and produced; the second step is heating debugging: the heating debugging system is built, the laser spot heating array is composed, the heating debugging is carried out, and the laser power value that meets the requirements is recorded; the third step is formal test: the formal test system is built, the position of the laser spot heating array is adjusted, and the formal test is carried out.

[0048] The beneficial effects are: specific steps and methods for heating scheme design and scheme implementation are given. In heating commissioning, a heat flux meter is used to calibrate the heat flux density value, which solves the problem of quantitative application of heat flux load in laser heating, and finally makes laser heating meet the test requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The accompanying drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention:

[0050] Figure 1 It is a schematic diagram of the overall system scheme involved in the present invention;

[0051] Figure 2 It is a schematic diagram of a 2×2 spot heating array composed of four laser beams;

[0052] Figure 3 This is a schematic diagram of the 2×2 installation method of four output heads;

[0053] Figure 4 It is a schematic diagram of the heating distance adjustment method;

[0054] Figure 5 This is a schematic diagram of using four laser beams to carry out structural thermal testing and heating debugging;

[0055] Figure 6 This is a schematic diagram of the formal test using four laser beams to carry out structural thermal testing.

[0056] Wherein: 1-computer, 2-controller, 3-laser, 4-power meter, 5-optical fiber, 6-output head, 7-output head bracket, 8-adjustable platform, 9-heat flow meter, 10-data acquisition device, 11-test piece, 301-laser 1, 302-laser 2, 303-laser 3, 304-laser 4, 401-power meter 1, 402-power meter 2, 403-power meter 3, 404-power meter 4, 501-optical fiber 1, 502-optical fiber 2, 503-optical fiber 3, 504-optical fiber 4, 601-output head 1, 602-output head 2, 603-output head 3, 604-output head 4, 6010-spot 1, 6020-spot 2, 6030-spot 3, 6040-spot 4, 1101-heated area of ​​test piece, 6000-laser beam 1 DETAILED DESCRIPTION

[0057] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0058] The structural thermal test carried out by the present invention is divided into three steps: the first step - heating scheme design; the second step - heating debugging; and the third step - formal test.

[0059] (I) The first step - heating scheme design

[0060] 1) Heating area design: such as Figure 2 As shown, 1101 is the heated area of ​​the test piece, which is circular in shape and has a diameter of φ80mm. The light spots output by the output heads 601 to 604 are all square. Four square light spots (6010, 6020, 6030, 6040) are used, and the size of a single light spot is 50mm×50mm. After the four light spots are arranged in a 2×2 array, the heating area is about 100mm×100mm, and the heating area completely covers the heated area 1101 of the test piece.

[0061] 2) Heating capacity design: The heating heat flux density required by the test is 2MW / m2, and the heating time is 100s. The laser power of each laser of lasers 301 to 304 is 6000W. When the spot area is 50mm×50mm, the maximum heat flux density that can be generated is 2.4MW / m2, which is greater than the test requirement (2MW / m2) and can meet the test requirements.

[0062] 3) Design and produce bracket 7: according to Figure 2 Heating scheme in, design and production of bracket 7. Figure 3 A schematic diagram of the installation using four output heads (601-604) is provided. Four mounting holes are designed on the bracket 7, corresponding to the four output heads (601-604). The relative positions of the mounting holes are also arranged in a 2×2 array. The bracket 7 is fastened to the adjustable platform 8 by screws.

[0063] (II) Step 2 - Heating Debugging

[0064] 1) Build a heating debugging system

[0065] according to Figure 4 The heating debugging system shown in the figure mainly includes: computer 1, controller 2, lasers 301-304, power meters 401-404, optical fibers 501-504, output heads 601-604, bracket 7, adjustable platform 8, heat flow meter 9, and data collector 10. The distance between the output heads 601-604 and the heat flow meter 9 is 1.5m.

[0066] 2) Composition of laser spot heating array

[0067] The control software of the operating computer 1 is used to start the lasers 301 to 304 to emit the indicator light, so that the indicator light is projected to the heated position. The indicator light spot size is exactly the same as the laser spot size used for heating in the formal test.

[0068] By adjusting the optical focusing device on the output heads 601-604, the spot size is proportionally scaled to 50 mm×50 mm.

[0069] By adjusting the angle adjustment device on the output heads 601-604, the angle of laser emission is finely adjusted so that the light spots 6010-6040 realize a 2×2 light spot heating array, and the distance between the light spots is controlled to be within a reasonable range (without too large gaps and too much overlap).

[0070] 3) Heat and debug and record the laser power value that meets the requirements

[0071] Place the heat flux meter 9 directly facing the light spot 6010. Operate the control software of the computer 1 to start the laser 301 to emit laser. Operate the data acquisition software of the computer 1 to collect the heat flux density value measured by the heat flux meter 9. When the heat flux density value is 2MW / m2, record the laser power value P1 measured by the power meter 401.

[0072] Place the heat flux meter 9 directly facing the light spot 6020. Operate the control software of the computer 1 to start the laser 302 to emit laser. Operate the data acquisition software of the computer 1 to collect the heat flux density value measured by the heat flux meter 9. When the heat flux density value is 2MW / m2, record the laser power value P2 measured by the power meter 402.

[0073] Place the heat flux meter 9 directly facing the light spot 6030. Operate the control software of the computer 1 to start the laser 303 to emit laser. Operate the data acquisition software of the computer 1 to collect the heat flux density value measured by the heat flux meter 9. When the heat flux density value is 2MW / m2, record the laser power value P3 measured by the power meter 403.

[0074] Place the heat flux meter 9 directly facing the light spot 6040. Operate the control software of the computer 1 to start the laser 304 to emit laser. Operate the data acquisition software of the computer 1 to collect the heat flux density value measured by the heat flux meter 9. When the heat flux density value is 2MW / m2, record the laser power value P4 measured by the power meter 404.

[0075] (III) Step 3: Formal Test

[0076] 1) Build a formal test system

[0077] according to Figure 5 The formal test system shown in the figure mainly includes: computer 1, controller 2, lasers 301-304, power meters 401-404, optical fibers 501-504, output heads 601-604, bracket 7, adjustable platform 8, data acquisition device 10, and test piece 11. The distance between the output heads 601-604 and the test piece 11 is 1.5 m.

[0078] 2) Adjust the position of the laser spot heating array

[0079] The control software of the operating computer 1 is used to start the lasers 301 - 304 to emit the indication light, so that the indication light is projected onto the test piece 11 .

[0080] By adjusting the translation and rotation devices of the adjustable platform 8 , the light spot heating array is made to face and completely cover the heated portion 1101 on the test piece 11 .

[0081] 3) Formal test

[0082] The control software of the operating computer 1 is used to set the powers of the lasers 301 to 304 to P1 to P4 respectively.

[0083] The control software of the computer 1 is operated to start the lasers 301 to 304 to emit laser light at the same time. The four laser beams are irradiated to the heated part 1101 on the test piece 11 .

[0084] The data acquisition software of the computer 1 is operated synchronously to record the temperature response data of the test piece. When the total heating time reaches 100 s, the control software of the computer 1 is operated to synchronously stop the lasers 301 to 304 from emitting lasers.

[0085] 4) End of the experiment

[0086] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A thermal strength test system for realizing large-area ultra-high temperature heating by splicing multiple laser beams, characterized in that: The system includes: computer, controller, laser, power meter, optical fiber, output head, bracket, adjustable platform, heat flow meter, data acquisition device; Among them, the computer is used to set and monitor the laser power and heat flux density value, and control the emission and shutdown of the laser and indicator light; the controller is used to transform the control signal emitted by the computer and transmit it to the laser; the laser is used to convert external electrical energy into laser or indicator light, emit laser during formal tests, and emit indicator light during laser alignment; the output head is used to emit the laser transmitted by the optical fiber after optical transformation; the data acquisition device collects the heat flux density value of the heat flow meter and transmits it to the computer.

2. According to claim 1, a thermal strength test system for realizing large-area ultra-high temperature heating by splicing multiple laser beams is characterized in that: The output head is provided with an angle adjustment device, which can fine-tune the angle of laser irradiation and further fine-tune the position of the light spot.

3. According to claim 1, a thermal strength test system for realizing large-area ultra-high temperature heating by splicing multiple laser beams is characterized in that: The output head is provided with an optical focusing device, which can realize proportional enlargement and reduction of the light spot by focusing, and does not change the distance between the laser head and the heated surface.

4. The thermal strength test system for realizing large-area ultra-high temperature heating by splicing multiple laser beams according to claim 1 is characterized in that: There are multiple lasers.

5. The thermal strength test system for realizing large-area ultra-high temperature heating by splicing multiple laser beams according to claim 1 is characterized in that: The size and shape of the heating area can be customized during laser heating.

6. A test method for a thermal strength test system for realizing large-area ultra-high temperature heating by splicing multiple laser beams according to any one of claims 1 to 5, characterized in that: include: Large area heating customization, laser alignment, heating distance adjustment, heating test.

7. The test method of a thermal strength test system for realizing large-area ultra-high temperature heating by splicing multiple laser beams according to claim 6 is characterized in that: The large-area heating customization method adopts a multi-beam laser splicing method to achieve large-area heating customization.

8. The test method of a thermal strength test system for realizing large-area ultra-high temperature heating by splicing multiple laser beams according to claim 6 is characterized in that: The large-area heating customization method specifically comprises the following steps: Step 1: The spot shape of a single laser beam is designed to be square or rectangular, and the energy distribution inside the spot is ensured to be uniform; Step 2: Combine multiple rectangular light spots to form the entire heating surface according to the shape of the heated surface; Step 3: Adjust the angle adjustment device on the output head to fine-tune the position of the light spot to solve the boundary connection problem between the light spots in the light spot heating array.

9. The test method of a thermal strength test system for realizing large-area ultra-high temperature heating by splicing multiple laser beams according to claim 6, characterized in that: The heating distance adjustment method is: by adjusting the optical focusing device on the output head, the light spot is proportionally enlarged or reduced by focusing, and the distance between the laser head and the heated surface is not changed.

10. The test method of a thermal strength test system for realizing large-area ultra-high temperature heating by splicing multiple laser beams according to claim 6, characterized in that: The heating test steps are as follows: Step 1: Heating and debugging test; set the laser power through the computer, and the laser emits laser light to irradiate the heat flux meter, and the heat flux density value is obtained by the heat flux meter test; adjust the laser power set by the computer to make the heat flux density value equal to the heat flux density value required by the test, and record the set laser power at this time; if multiple heat flux density values ​​are involved, repeat the above work and test them one by one; Step 2: Formal test: Remove the heat flux meter and install the formal test piece in the same position. After adjusting the spot position, start heating according to the laser power recorded in the first step as the set value, and then start the formal heating test until the end of the test.

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