Dynamic elastic thin plate modal test platform

Abstract

The utility model relates to a dynamic elastic thin plate modal testing platform, and discloses a moving plate strip modal measuring platform which is simple and accurate to operate, and the technical scheme is that the device comprises a frame, a driving roller unit, a fixed roller unit, a tensioning roller unit, a sink roller unit, a plate strip, a data acquisition and processing unit and the like. The driving roller, the fixed roller and the tensioning roller are mounted on the upper edge of the mounting rack I; the sink roll is mounted at the lower edge of the mounting rack II; the tensioning device is installed in cooperation with the tensioning roller. The data acquisition unit comprises a modal force hammer, a force sensor and a displacement sensor, the force sensor is used for testing tensile force, data are acquired through the force sensor and the displacement sensor and input into a data processing end, and modal analysis is performed on a DASP vibration test analysis platform. The simple and effective tensioning device and the driving device of the platform enable the platform to accurately and comprehensively test the modals of the plate strip under various working conditions. According to the utility model, the problem of lack of plate and strip modal experiment platforms and technologies in a motion state is solved, and the functions are comprehensive.

Description

Technical Field

[0001] The utility model belongs to the technical field of detection equipment, and specifically relates to a modal testing platform for elastic thin plates in a moving state. Background Art

[0002] During the production process of products such as plates and strips, various forms of vibration are usually generated. As the plates and strips become thinner and wider, their flexibility characteristics are significantly enhanced, which greatly harms the normal operation of the production line and product quality. Therefore, higher requirements are placed on their vibration control. Accurate analysis of the natural frequency and vibration characteristics of thin plate components is of great significance for their vibration control. Based on the modal parameters, the modal sensitivity can be further analyzed to provide a reference for structural optimization design. Experimental modal analysis, as the inverse process of theoretical modal analysis, is an important method to verify the reliability of finite element analysis.

[0003] The existing modal testing platforms and devices are mainly modal testing devices for plate-like rigid parts, and the test conditions are usually relatively simple, and the strip modal under complex working conditions cannot be tested. The patent utility model with publication number CN112161799A provides a test method for a flexible strip under static conditions. This utility model solves the problem of testing the strip modal under various working conditions. However, in the actual production of the strip, the strip is generally in a moving state, and the utility model does not solve the problem of modal testing of the strip in a moving state. The utility model can simulate the motion state of the strip in actual production and test the strip modal under motion. In the patent with publication number CN112161799A, since the strip is in a static state, the measuring points can be directly marked on the strip for modal testing, but this method is not suitable for dynamic strip testing. Therefore, compared with the patent, the utility model designs a device for setting excitation points on the moving strip. The device does not need to touch the strip, reduces the influence of human factors, and improves the accuracy of the results.

[0004] The production process of the plate and strip has complex working conditions, including tension, plate and strip size, material, rotation speed, etc. These conditions have an important impact on the plate and strip mode. Therefore, testing the impact of different working conditions on the performance of the plate and strip is extremely important to ensure the normal operation of the production line and product quality. In the past, modal testing lacked a standardized test process. In the actual test process, it is necessary to avoid interference from human factors, that is, to minimize the impact of people on the accuracy of the test results. Therefore, a set of standardized plate and strip modal test processes is needed to ensure that the test can be repeated. At present, the selection of data acquisition tools in modal testing is unreasonable, the analysis and processing of data are inefficient, and the experimental results obtained are not accurate enough. The experimental data collected by the sensor that directly contacts the plate and strip has an irremovable error effect, and most of the data acquisition equipment for modal testing is in direct contact with the plate and strip, and the modal test analysis platform is also relatively backward. Therefore, advanced measurement tools and data processing platforms are needed to ensure the accuracy of the test results. Utility Model Content

[0005] The utility model aims to solve the problem of lack of modal test devices in the research and development of existing plate and strip production technology, and provides a thin plate modal test platform.

[0006] A dynamic elastic thin plate modal testing platform comprises a frame, a driving roller unit, a fixed roller unit, a tensioning roller unit, a sinking roller unit, a plate belt, a laser light mounting frame, and a data acquisition and processing unit.

[0007] Furthermore, the frame includes two rectangular mounting frames I and II arranged vertically, and two right-angle tripods III. The two rectangular mounting frames have the same structure and both include two long support rods and two short support rods. The middle parts of the two long support rods are connected by a connecting rod. The two rectangular mounting frames are fixed together by four columns. In order to improve the strength of the frame, a cable-stayed beam is arranged between the long support rods and the columns; the right-angle tripod III is installed on one side of two of the columns.

[0008] Furthermore, the driving roller unit includes a driving roller, two driving roller seat bearings, two driving roller bearing seat base plates, two pulleys, a synchronous belt, a motor and a motor mounting base plate. The motor mounting base plate is fixedly mounted on the upper surface of the right-angle tripod III, and the motor is mounted on the motor mounting base plate. The driving roller bearing seat base plate is fixed to one side of the upper surface of the two long support rods of the rectangular mounting frame I. The driving roller is fixedly mounted on the driving roller bearing seat base plate 18 through the driving roller seat bearing. Pulleys are installed on the output end of the motor and one side of the driving roller, and the two pulleys are connected by synchronous belt transmission.

[0009] Furthermore, the fixed roller unit includes two fixed roller bearing seat base plates, a fixed roller and two fixed roller belt seat bearings, the fixed roller bearing seat base plates are fixed to the other side of the upper surface of the two long support rods of the rectangular mounting frame I, and the fixed roller is fixedly mounted on the fixed roller bearing seat base plates through the fixed roller belt seat bearings.

[0010] Further, the tension roller unit includes two guide rails, which are fixed to the left side of the middle part of the upper surface of the two long support rods of the rectangular mounting frame I. The two flat plates are slidably connected to the guide rails through sliders. The tension roller is fixedly installed on the flat plate through the tension roller belt seat bearing. One end of the two flat plates is fixedly connected through a vertical plate. Two L-shaped push plates are arranged on the side of the vertical plate close to the fixed roller unit. Two force sensors are arranged on the vertical plate. The push plate is fixedly installed on the upper surface of the two long support rods of the rectangular mounting frame I. The push plate is provided with a threaded hole. The tension bolt passes through the threaded hole and abuts against the force sensor. The vertical plate is driven to move back and forth by the movement of the tension bolt in the screw hole of the push plate to adjust the tension force. The force sensor is fixed on the vertical plate. When the tension bolt is screwed in, pressure acts on the force sensor. The magnitude of the tension force is measured by the force sensor.

[0011] Furthermore, the sinking roller unit includes a cantilever frame and a sinking roller cantilever. The cantilever frame is fixedly mounted on the lower surface of the two long support rods of the rectangular mounting frame II. Two sinking roller cantilevers are fixedly mounted below the cantilever frame. The sinking roller is arranged between the two sinking roller cantilevers. Threaded holes are arranged at both ends of the sinking roller, and the sinking roller and the sinking roller cantilever are completely constrained by stud bolts on the end cover of the sinking roller shaft.

[0012] Furthermore, the laser light mounting frame includes two vertical rods, 13 horizontal rods are fixed at equal intervals between the vertical rods, four short rods are fixedly installed on both sides of the vertical rods, and the laser light mounting frame is fixedly installed on the inner sides of two of the columns 1 through the short rods, wherein the distance between two adjacent horizontal rods is 100 mm, and 5 holes are evenly spaced on each horizontal rod, for a total of 65 holes, and the distance between two adjacent holes on each horizontal rod is 50 mm. Counting from top to bottom, the second hole on the sixth horizontal rod is hole A, and the fourth hole on the eighth horizontal rod is hole B. No laser lights are installed on holes A and B, and a miniature laser light is installed on each of the remaining 63 holes.

[0013] Furthermore, the data acquisition and processing unit includes a modal force hammer, a PC, a dynamic signal acquisition instrument and a tripod IV. The tripod IV is arranged on the right side of the frame. The first laser displacement sensor and the second laser displacement sensor are respectively installed on the left and right sides of the tripod IV. Among them, the first laser displacement sensor corresponds to the position of hole A, and the second laser displacement sensor corresponds to the position of hole B.

[0014] Furthermore, the PC is installed with DASP vibration test and analysis platform software, which is composed of characteristic system realization algorithm ERA and modal confidence judgment criterion MAC.

[0015] A method for using an elastic thin plate modal testing platform comprises the following steps:

[0016] S1: Marking test points, preparation of test tools and debugging equipment;

[0017] S2: Test the motion mode of elastic thin plate;

[0018] S3: perform data processing and calculation;

[0019] S4: Test the elastic thin plate modes under different conditions.

[0020] Furthermore, step S1 is specifically as follows:

[0021] Connect the modal force hammer, the first laser displacement sensor and the second laser displacement sensor to the PC, turn on the first laser displacement sensor and the second laser displacement sensor, turn on the micro laser lights on the laser light mounting frame, and all lasers are irradiated on the strip and 65 measuring points are displayed. Adjust the tension to the specified value.

[0022] Furthermore, step S2 is specifically as follows:

[0023] Turn on the motor and adjust the speed to meet the experimental requirements. Use a modal force hammer to knock on each measuring point on the plate in turn and collect signals through the first laser displacement sensor and the second laser displacement sensor. To obtain the best data, knock on each measuring point three times and collect signals three times. Then continue to knock on the next measuring point on the thin plate, knock three times and collect signals three times. Repeat the above steps until all tests of 65 measuring points are completed.

[0024] When the modal force hammer strikes, it is required to strike the same position in the same direction each time, the excitation force should be as consistent as possible, and the hammering should be crisp and clear to avoid secondary strikes.

[0025] Furthermore, step S3 is specifically as follows:

[0026] Based on the vibration theory of multi-degree-of-freedom systems, the mathematical model of the pulse frequency response function of the N-degree-of-freedom thin plate characterized by modal parameters is used to determine the unknown parameters in the model through the collected signals, that is, curve fitting, and the frequency response function between each response point and the excitation point of the thin plate can be obtained. Then, the algorithm ERA is used to analyze and process the various vibration modes and their frequencies of the elastic thin plate under the constraint state, and then the modal confidence judgment criterion MAC is used to make a judgment to verify the accuracy of the test mode. Among them, the response point is the point monitored by the first laser displacement sensor and the second laser displacement sensor, and the excitation point is the point struck by the modal force hammer. There are 65 excitation points in total.

[0027] Furthermore, step S4 is specifically as follows:

[0028] According to the experimental requirements, replace the sinking rollers and elastic sheets of different materials and sizes, adjust the tension and motor speed, repeat steps S2-S3, and record the modal values ​​under different conditions.

[0029] The utility model adopts the above technical solution, which can bring the following beneficial effects:

[0030] First: a design scheme and usage method of a dynamic elastic thin plate modal experimental platform is proposed, which solves the problem of lack of dynamic thin plate modal experimental devices and methods;

[0031] Second: Design a device to accurately divide and locate the measuring points of the plate strip to solve the problem of position error when the hammer hits the plate strip in previous plate strip modal tests, making the data collected in the experiment more accurate.

[0032] Third: The motor drive device is designed to test the influence of different speed conditions on the thin plate mode, solving the problem of adjusting the plate and strip movement speed.

[0033] Fourth: A tension adjustment device is designed to test the effect of different tensions on the modal state of the flexible strip;

[0034] Fifth: Suitable for testing the characteristics of plates and strips of different thicknesses, widths, materials (aluminum / copper / steel / silicon steel), etc.

[0035] Sixth: Standardize the dynamic elastic thin plate modal test process and provide detailed test steps to ensure the repeatability and standardization of the experiment.

[0036] Seventh: The use of laser displacement sensor detection and DASP vibration test analysis platform can ensure the accuracy of collected data and improve the efficiency of data processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is an axonometric drawing of the test platform of the utility model;

[0038] Figure 2This is a front side view of the test platform of the utility model;

[0039] Figure 3 for Figure 1 Axonometric diagram of the middle frame section;

[0040] Figure 4 is a partial view of a fixed roller unit;

[0041] Figure 5 It is a partial enlarged view of the tension roller unit;

[0042] Figure 6 is a partial view of a driving roller unit;

[0043] Figure 7 is a partial view of the sinking roller unit;

[0044] Figure 8 is the schematic diagram of the motor;

[0045] Fig. 9 It is a schematic diagram of the plate strip structure;

[0046] Fig.10 This is a schematic diagram of the measuring points of the plate and strip;

[0047] Fig.11 This is a schematic diagram of the laser light mounting bracket. DETAILED DESCRIPTION

[0048] The technical solution of the utility model will be clearly and completely described below through specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of them. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0049] Depend on Figures 1 to 11 As shown, a dynamic elastic thin plate modal testing platform includes a frame, a driving roller unit, a fixed roller unit, a tensioning roller unit, a sinking roller unit, a plate belt, a laser light mounting frame 6, and a data acquisition and processing unit.

[0050] The frame includes two rectangular mounting frames I and II arranged up and down, and two right-angle tripods III. The two rectangular mounting frames have the same structure and both include two long support rods 3 and two short support rods 2. The middle parts of the two long support rods 3 are connected by a connecting rod 5. The two rectangular mounting frames are fixed together by four columns 1. In order to improve the strength of the frame, a cable-stayed beam 4 is arranged between the long support rods 3 and the columns 1; the right-angle tripod III is installed on one side of two of the columns 1.

[0051] The driving roller unit includes a driving roller 17, two driving roller seat bearings 27, two driving roller bearing seat base plates 18, two pulleys 28, a synchronous belt 29, a motor 19 and a motor mounting base plate 20. The motor mounting base plate 20 is fixedly mounted on the upper surface of the right-angle tripod III, the motor 19 is mounted on the motor mounting base plate 20, the driving roller bearing seat base plate 18 is fixed to one side of the upper surface of the two long support rods 3 of the rectangular mounting frame I, the driving roller 17 is fixedly mounted on the driving roller bearing seat base plate 18 through the driving roller seat bearings 27, the output end of the motor 19 and one side of the driving roller 17 are both equipped with pulleys 28, and the two pulleys 28 are connected through a synchronous belt 29.

[0052] The fixed roller unit includes two fixed roller bearing seat base plates 8, a fixed roller 7 and two fixed roller belt seat bearings 24. The fixed roller bearing seat base plates 8 are fixed to the other side of the upper surface of the two long support rods 3 of the rectangular mounting frame I, and the fixed roller 7 is fixedly mounted on the fixed roller bearing seat base plates 8 through the fixed roller belt seat bearings 24.

[0053] The tension roller unit comprises two guide rails 10, which are fixed on the left side of the middle part of the upper surface of the two long support rods 3 of the rectangular mounting frame I. The two flat plates 11 are slidably connected to the guide rails 10 through the slider 26. The tension roller 12 is fixedly installed on the flat plate 11 through the tension roller belt seat bearing 25. One end of the two flat plates 11 is fixedly connected through the vertical plate 13. Two L-shaped push plates 15 are arranged on the side of the vertical plate 13 close to the fixed roller unit. Two force sensors 14 are arranged on the vertical plate 13. The push plate 15 is fixedly installed on the upper surface of the two long support rods 3 of the rectangular mounting frame I. The push plate 15 is provided with a threaded hole. The tension bolt 16 passes through the threaded hole and abuts against the force sensor 14. The vertical plate 13 is driven to move back and forth by the movement of the tension bolt 16 in the screw hole of the push plate 15 to adjust the tension. The force sensor 14 is fixed on the vertical plate 13. When the tension bolt 16 is screwed in, the pressure acts on the force sensor 14. The magnitude of the tension is measured by the force sensor 14.

[0054] The sinking roller unit includes a cantilever frame 21 and a sinking roller cantilever 22. The cantilever frame 21 is fixedly mounted on the lower surface of the two long support rods of the rectangular mounting frame II. Two sinking roller cantilevers 22 are fixedly mounted below the cantilever frame 21. The sinking roller 23 is arranged between the two sinking roller cantilevers 22. Threaded holes are arranged at both ends of the sinking roller 23, and the stud bolts on the sinking roller shaft end cover 30 are used to completely constrain it and the sinking roller cantilever 22.

[0055] The laser light mounting frame 6 comprises two vertical bars 6-1, 13 horizontal bars 6-2 are fixed at equal intervals between the vertical bars 6-1, four short bars 6-3 are fixedly installed on both sides of the vertical bars 6-1, and the laser light mounting frame 6 is fixedly installed on the inner sides of two of the columns 1 through the short bars 6-3, wherein the distance between two adjacent horizontal bars 6-2 is 100 mm, and 5 holes are evenly spaced on each horizontal bar 6-2, for a total of 65 holes, and the distance between two adjacent holes on each horizontal bar 6-2 is 50 mm. Counting from the top to the bottom, the second hole on the sixth horizontal bar is hole A, and the fourth hole on the eighth horizontal bar is hole B. No laser lights are installed on holes A and B, and a miniature laser light 33 is installed on each of the remaining 63 holes.

[0056] The data acquisition and processing unit includes a modal force hammer, a PC, a dynamic signal acquisition instrument and a tripod IV. The tripod IV is arranged on the right side of the frame. The first laser displacement sensor 31 and the second laser displacement sensor 32 are respectively installed on the left and right sides of the tripod IV. Among them, the first laser displacement sensor 31 corresponds to the position of hole A, and the second laser displacement sensor 32 corresponds to the position of hole B.

[0057] The DASP vibration test and analysis platform software is installed on the PC. The DASP vibration test and analysis platform software consists of an eigensystem implementation algorithm ERA and a modal confidence determination criterion MAC.

[0058] The number of measuring points is related to whether the modal characteristics of the structure can be fully obtained. The measuring point positions should be reasonably distributed so that each modal vibration shape can be uniquely distinguished. Therefore, it is necessary to set a sufficient number of measuring points. For elastic thin plates, considering the position distribution of the actual hot-dip galvanizing production line, determine the key area of ​​the elastic thin plate, that is, the vertical strip area, the strip located between the submerged roller unit and the fixed roller unit, such as Fig. 9 The V zone is shown in the figure. This zone is the vertical rise section of the elastic sheet after the galvanizing is completed. The vibration of the elastic sheet will directly affect the quality of galvanizing and ultimately affect the product quality. Therefore, this section of the elastic sheet is selected as the research object.

[0059] A method for using an elastic thin plate modal testing platform comprises the following steps:

[0060] S1: Marking test points, preparation of test tools and debugging equipment;

[0061] Connect the modal force hammer, the first laser displacement sensor 31 and the second laser displacement sensor 32 to the PC, turn on the first laser displacement sensor 31 and the second laser displacement sensor 32, turn on the 63 micro laser lights 33 on the laser light mounting frame 6, all lasers are irradiated on the strip and 65 measuring points are displayed. Adjust the tension to the specified value.

[0062] S2: Test the motion mode of elastic thin plate;

[0063] Turn on the motor 19 and adjust the speed to meet the experimental requirements. Use a modal force hammer to knock on 65 measuring points on the plate in turn and collect signals through the first laser displacement sensor 31 and the second laser displacement sensor 32. To obtain the best data, knock on each measuring point three times and collect signals three times. Then continue to knock on the next measuring point on the thin plate, knock three times and collect signals three times. Repeat the above steps until all tests on 65 measuring points are completed.

[0064] When the modal force hammer strikes, it is required to strike the same position in the same direction each time, the excitation force should be as consistent as possible, and the hammering should be crisp and clear to avoid secondary strikes.

[0065] S3: perform data processing and calculation;

[0066] Based on the vibration theory of multi-degree-of-freedom systems, the mathematical model of the pulse frequency response function of the N-degree-of-freedom thin plate characterized by modal parameters, the unknown parameters in the model are determined by the collected signals, that is, curve fitting, and the frequency response function between each response point and the excitation point of the thin plate can be obtained. Then, the algorithm ERA is used to analyze and process to obtain the vibration modes and frequencies of the elastic thin plate under the constraint state, and then the modal confidence judgment criterion MAC is used to make a judgment to verify the accuracy of the test mode. Among them, the response point is the point monitored by the first laser displacement sensor 31 and the second laser displacement sensor 32, and the excitation point is the point struck by the modal force hammer. There are 65 excitation points in total.

[0067] S4: Test the elastic thin plate modes under different conditions.

[0068] According to the experimental requirements, replace the sinking rollers and elastic sheets of different materials and sizes, adjust the tension and motor speed, repeat steps S2-S3, and record the modal values ​​under different conditions.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A dynamic elastic thin plate modal test platform, characterized in that: It includes a frame, a driving roller unit, a fixed roller unit, a tensioning roller unit, a sinking roller unit, a plate belt, a laser light mounting frame (6), and a data acquisition and processing unit; The frame comprises two rectangular mounting frames I and II arranged vertically, and two right-angle tripod frames III. The two rectangular mounting frames have the same structure and both comprise two long support rods (3) and two short support rods (2). The middle parts of the two long support rods (3) are connected by a connecting rod (5). The two rectangular mounting frames are fixed together by four columns (1). In order to improve the strength of the frame, a diagonal beam (4) is arranged between the long support rods (3) and the columns (1); the right-angle tripod frames III are installed on one side of two of the columns (1). The driving roller unit comprises a driving roller (17), two driving roller seat bearings (27), two driving roller bearing seat bottom plates (18), two pulleys (28), a synchronous belt (29), a motor (19) and a motor mounting bottom plate (20), wherein the motor mounting bottom plate (20) is fixedly mounted on the upper surface of a right-angle tripod III, the motor (19) is mounted on the motor mounting bottom plate (20), the driving roller bearing seat bottom plate (18) is fixed on one side of the upper surface of two long support rods (3) of the rectangular mounting frame I, the driving roller (17) is fixedly mounted on the driving roller bearing seat bottom plate (18) via the driving roller seat bearings (27), the output end of the motor (19) and one side of the driving roller (17) are both mounted with pulleys (28), and the two pulleys (28) are connected by a synchronous belt (29); The fixed roller unit comprises two fixed roller bearing seat bottom plates (8), a fixed roller (7) and two fixed roller belt seat bearings (24), wherein the fixed roller bearing seat bottom plates (8) are fixed to the other side of the upper surface of the two long support rods (3) of the rectangular mounting frame I, and the fixed roller (7) is fixedly mounted on the fixed roller bearing seat bottom plates (8) via the fixed roller belt seat bearings (24); The tension roller unit comprises two guide rails (10), the guide rails (10) being fixed to the left side of the middle part of the upper surface of the two long support rods (3) of the rectangular mounting frame I, the two flat plates (11) being slidably connected to the guide rails (10) via a slider (26), the tension roller (12) being fixedly mounted on the flat plate (11) via a tension roller seat bearing (25), one end of the two flat plates (11) being fixedly connected via a vertical plate (13), two L-shaped push plates (15) being arranged on one side of the vertical plate (13) close to the fixed roller unit, and two force sensors (15) being arranged on the vertical plate (13) 4), a push plate (15) is fixedly mounted on the upper surface of the two long support rods (3) of the rectangular mounting frame I, and a threaded hole is opened on the push plate (15), and a tensioning bolt (16) passes through the threaded hole and abuts against the force sensor (14); the movement of the tensioning bolt (16) in the threaded hole of the push plate (15) drives the vertical plate (13) to move back and forth, and the tensioning force is adjusted. The force sensor (14) is fixed on the vertical plate (13), and when the tensioning bolt (16) is screwed in, pressure acts on the force sensor (14), and the magnitude of the tensioning force is measured by the force sensor (14).

2. A dynamic elastic thin plate modal testing platform as claimed in claim 1, characterized in that: The sinking roller unit comprises a cantilever frame (21) and a sinking roller cantilever (22); the cantilever frame (21) is fixedly mounted on the lower surface of two long support rods of the rectangular mounting frame II; two sinking roller cantilevers (22) are fixedly mounted below the cantilever frame (21); the sinking roller (23) is arranged between the two sinking roller cantilevers (22); threaded holes are arranged at both ends of the sinking roller (23), and the sinking roller and the sinking roller cantilever (22) are completely constrained by stud bolts on the sinking roller shaft end cover (30).

3. A dynamic elastic thin plate modal testing platform as claimed in claim 1, characterized in that: The laser light mounting frame (6) comprises two vertical bars (6-1), 13 horizontal bars (6-2) are fixed at equal intervals between the vertical bars (6-1), four short bars (6-3) are fixedly mounted on both sides of the vertical bars (6-1), and the laser light mounting frame (6) is fixedly mounted on the inner sides of two of the vertical columns (1) via the short bars (6-3), wherein the distance between two adjacent horizontal bars (6-2) is 100 mm, and each horizontal bar (6-2) is provided with five holes at equal intervals, for a total of 65 holes, and the distance between two adjacent holes on each horizontal bar (6-2) is 50 mm. Counting from the top to the bottom, the second hole on the sixth horizontal bar is hole A, and the fourth hole on the eighth horizontal bar is hole B. No laser lights are mounted on holes A and B, and a micro laser light (33) is mounted on each of the remaining 63 holes.

4. A dynamic elastic thin plate modal testing platform as claimed in claim 1, characterized in that: The data acquisition and processing unit comprises a modal force hammer, a PC, a dynamic signal acquisition instrument and a tripod IV, wherein the tripod IV is arranged on the right side of the frame, and a first laser displacement sensor (31) and a second laser displacement sensor (32) are respectively installed on the left and right sides of the tripod IV, wherein the first laser displacement sensor 31 corresponds to the position of hole A, and the second laser displacement sensor (32) corresponds to the position of hole B. The PC is installed with DASP vibration test analysis platform software, wherein the DASP vibration test analysis platform software consists of a characteristic system realization algorithm ERA and a modal confidence judgment criterion MAC.

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