Multi-angle low-speed impact device for inner surface of composite arc-shaped plate and testing method thereof

Abstract

The invention provides a composite arc-shaped plate inner surface multi-angle low-speed impact device and a test method thereof, and belongs to the technical field of composite low-speed impact tests.The composite arc-shaped plate inner surface multi-angle low-speed impact device comprises a fixing assembly and a punch assembly, the punch assembly is located above the fixing assembly and installed at the bottom of a moving mechanism, and the height of a punch is controlled through the moving mechanism; therefore, the impact potential energy of the punch is obtained. The punch applies an impact load to the test piece, the impact force information in the process that the punch impacts the test piece is obtained, a curve of the load and time of the test piece is obtained, the impact mechanical property of the composite material can be effectively evaluated, and a test basis is provided for qualification judgment of the composite material. According to the invention, multi-angle impact of the inner surface of the arc-shaped plate composite material at the same impact point can be realized, and the impact mechanical properties of the arc-shaped plate composite material at different angles can be effectively evaluated.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of composite material low-speed impact test, and particularly relates to a composite material arc-shaped plate inner surface multi-angle low-speed impact device and a test method thereof. BACKGROUND

[0002] Composite materials have been widely used in the fields of aviation, aerospace, shipbuilding and automobile due to their excellent performance. In actual working conditions, the inner surfaces of some arc-shaped plate composite materials are prone to be damaged under load impact in different directions, such as aircraft engine containment rings, automobile wheel mudguards, and pipeline inner walls. Therefore, studying the impact response of arc-shaped plate composite material inner surfaces under different impact angles is more in line with actual engineering applications.

[0003] At present, the standard low-speed impact testing machine can only test the low-speed impact of flat plate composite materials and cannot clamp arc-shaped plate composite materials. At the same time, since the impact hammer head of the low-speed impact testing device remains in the vertical direction and is fixed, it is of great scientific significance and engineering practical value to develop a composite material arc-shaped plate inner surface multi-angle low-speed impact device and a test method thereof.

[0004] The current low-speed impact test standard is ASTM D7136, which is limited to drop hammer impact test of flat plate composite materials with fixed size and impact point. In actual working conditions, the shape and impact position of composite materials are not unique. In view of the above problems, domestic researchers have continuously improved the clamps. For example: the invention patent CN114112737B invents a drop hammer impact clamp with variable sample size, impact point and boundary conditions, which changes the impact boundary and impact point through pulleys, but the impact angle of the clamp is still vertical. The invention patent CN115326551A discloses a multi-angle impact clamp for a drop hammer testing machine, which realizes the change of impact angle by adjusting the height of one end, but the clamp is limited to drop hammer low-speed impact test of flat plate structure, and the angle changing process is relatively complex.

[0005] In summary, the existing test device can only test flat plate composite materials, but there are a large number of arc-shaped plate structures in the actual application of composite materials, and low-speed impact test of only flat plate composite materials cannot analyze the performance of arc-shaped plate structures. It is worth noting that since the arc-shaped plate is a structure with curvature, multi-angle impact test of arc-shaped plate composite materials needs to consider the impact point position. SUMMARY

[0006] The problem to be solved by the present application is to provide a composite material arc-shaped plate inner surface multi-angle low-speed impact device and a test method thereof.

[0007] To solve the above technical problems, the technical scheme adopted by the present application is: a multi-angle low-speed impact device for the inner surface of a composite material arc-shaped plate, comprising a fixed component and a punch component, the punch component is located above the fixed component, the fixed component comprises an upper fixed plate and a lower fixed plate, the upper fixed plate is used for fixing a test piece, the lower fixed plate is used for fixing the test piece and changing the angle of the test piece, the upper fixed plate and the lower fixed plate are cooperatively arranged to fix the test piece together; the upper fixed plate is a concave panel structure, the upper fixed plate is provided with upper fixed clamping portions at both ends, and the upper fixed plate is provided with an impact hollow groove at the center position; the lower fixed plate is installed on a fixed platform, the lower fixed plate is a concave block structure, the lower fixed plate is provided with a groove at the center position, the groove is concentrically arranged with the impact hollow groove, the lower fixed plate is provided with lower fixed clamping portions at both ends of the upper surface, the lower fixed clamping portions are matched with the upper fixed clamping portions, the lower fixed plate is provided with a first clamping groove structure at the bottom for changing the angle, the fixed platform is provided with a second clamping groove structure on the upper surface, the first clamping groove structure and the second clamping groove structure are cooperatively arranged, and the engagement of the first clamping groove structure and the second clamping groove structure at different positions provides the change of the angle of the test piece; the punch component is installed at the bottom of a moving mechanism, the moving mechanism is connected with a frame through a guide rail, the moving mechanism moves up and down along the guide rail, and the frame and the guide rail provide support and displacement for the moving mechanism and the punch component.

[0008] Further, the angle change range of the test piece is 60°-90°.

[0009] Further, the punch component comprises a counterweight and a punch, the punch is installed at the bottom of the counterweight, and an impact force signal receiving device is installed inside the punch for obtaining the impact signal of the punch. The impact force signal receiving device is communicatively connected with a computer, and the mechanical curve of the test piece is obtained based on the impact force information. The punch component is the impact of different angles at the same impact point.

[0010] Further, the counterweight and the moving mechanism are detachably connected to realize the release and grabbing of the punch component.

[0011] Further, the counterweight is provided with a first limiter, the guide rail is provided with a second limiter, the second limiter can move on the guide rail, the second limiter and the moving mechanism are located on two parallel tracks on the guide rail, and the strokes do not affect each other. The first limiter and the second limiter are both communicatively connected with the computer, and they are existing infrared limit devices which are triggered by shielding infrared rays. They can mark the zero position of the test.

[0012] Further, the fixed assembly is provided with a liftable buffer device on both sides for contacting the punch assembly, which can not only limit the end position of the impact stroke, but also control the impact energy of the punch to prevent overloading impact and ensure the accuracy of test data.

[0013] Further, the lower fixed plate is provided with a protractor on one side.

[0014] The application also provides a multi-angle low-speed impact test method for the inner surface of a composite arc plate, including the following steps: S1, the test piece is placed between the upper fixed plate and the lower fixed plate, the test piece is tightly attached to the upper fixed plate and the lower fixed plate, the impact point exposed by the hollow groove is aligned with the punch, and it is ensured that the punch and the impact point position of the test piece are in the same straight line; S2, the relative position between the first clamping groove structure and the second clamping groove structure is adjusted so that the impact angle meets the test requirements; S3, the punch assembly is controlled to descend, and the punch is tightly attached to the test piece, and this position is marked as the zero position; S4, when the punch is at the zero position, the limiters are adjusted so that the first limiter and the second limiter are located on the same horizontal plane; S5, the test parameter values are set, including the impact energy and the impact height; S6, the punch is raised from the zero position to the parameter setting position; S7, the punch is released, the punch contacts the test piece and collects signals, and the signals are transmitted to a computer for analysis, and a load-time mutual relationship curve is output.

[0015] Due to the above technical scheme, the application has the following beneficial effects: The application can realize multi-angle impact of the inner surface of the arc plate composite material at the same impact point, and can effectively evaluate the anti-impact mechanical properties of the arc plate composite material under different angles.

[0016] It can be seen that the application solves the problems in the prior art, fills the gap of multi-angle low-speed impact test of the concave structure composite material, forms a test method for exploring the multi-angle low-speed impact of the inner surface of the arc plate composite material, can adjust the impact angle, is suitable for low-speed impact test under different impact angles, and has the advantages of simple structure, good stability, guaranteed test precision under large impact energy oblique impact, and more accurate test of the low-speed impact performance of the arc plate composite material under actual working conditions. BRIEF DESCRIPTION OF DRAWINGS

[0017] The present application will be described in detail below with reference to the drawings and in conjunction with examples, the advantages and implementation manners of the present application will be more obvious, wherein the contents shown in the drawings are only used for the explanation and illustration of the present application, and do not constitute any sense of limitation to the present application, and in the drawings: Figure 1 It is a structural schematic diagram of the present application.

[0018] Figure 2 It is a structural schematic diagram of the upper fixing plate of the present application.

[0019] Figure 3 It is a front view of the upper fixing plate of the present application.

[0020] Figure 4 It is a structural schematic diagram of the lower fixing plate of the present application.

[0021] Figure 5 It is a front view of the lower fixing plate of the present application.

[0022] Figure 6 It is a structural schematic diagram of the fixed platform of the present application.

[0023] Figure 7 It is a front view of the fixed platform of the present application.

[0024] Figure 8 It is a load-time curve of the present application.

[0025] In the figure: 1, upper fixing plate; 2, lower fixing plate; 3, fixed platform; 4, protractor; 5, buffer device; 6, moving mechanism; 7, frame; 8, guide rail; 9, first limiter; 10, groove; 11, first clamping groove structure; 12, second clamping groove structure; 13, impact hollow groove; 14, upper fixing clamping part; 15, lower fixing clamping part; 16, counterweight; 17, punch; 18, second limiter. DETAILED DESCRIPTION

[0026] As Figures 1 to 7 shown, the present application is a multi-angle low-speed impact device for the inner surface of a composite material arc-shaped plate, which comprises a fixing assembly and a punch assembly, the punch assembly is located above the fixing assembly, the fixing assembly comprises an upper fixing plate 1 and a lower fixing plate 2, the upper fixing plate 1 is used for fixing a test piece, the lower fixing plate 2 is used for fixing the test piece and changing the angle of the test piece, the upper fixing plate 1 and the lower fixing plate 2 are cooperatively arranged, and both of them fix the test piece through screws.

[0027] the upper fixing plate 1 is a concave panel structure with a curvature radius of 50 mm, the upper fixing plate 1 is provided with an upper fixing clamping part 14 at both ends, and the impact hollow groove 13 is arranged at the center position of the upper fixing plate 1.

[0028] The lower fixed plate 2 is installed on the fixed platform 3, the lower fixed plate 2 is a concave block structure with a curvature radius of 50mm, a groove 10 is arranged at the center position of the lower fixed plate 2, the groove 10 is arranged concentrically with the impact hollow groove 13, lower fixed clamping parts 15 are arranged at both ends of the upper surface of the lower fixed plate 2, which cooperate with the upper fixed clamping parts 14, a first clamping groove structure 11 for changing the angle is arranged at the bottom of the lower fixed plate 2, a second clamping groove structure 12 is arranged on the upper surface of the fixed platform 3, the first clamping groove structure 11 and the second clamping groove structure 12 are arranged in cooperation, and the engagement of the first clamping groove structure 11 and the second clamping groove structure 12 at different positions provides the change of the angle of the test piece. When the angle changes, the position of the first clamping groove structure 11 of the lower fixed plate 2 is changed, and the position of the second clamping groove structure 12 on the fixed platform 3 remains unchanged.

[0029] In this embodiment, the angle change range of the test piece is 60°-90°, and the minimum unit of angle change is 1°.

[0030] In this embodiment, the size of the upper fixed plate 1 and the lower fixed plate 2 is 150mm*100mm, the 150mm direction is the curved surface direction, the curved surface span is 100mm, and the length of the upper fixed clamping part 14 and the lower fixed clamping part 15 on both sides of the curved surface is 25mm, which is the clamping length of the test piece. Based on the 100mm curved surface span, the arc length of different curvature radii can be designed, and the curvature radius can be designed to meet the test requirements of different curvatures. In this embodiment, the arc length with a curvature radius of 50mm is taken as an example for description.

[0031] In this embodiment, the size of the test sample is 150mm*100mm*4mm.

[0032] The punch assembly is installed at the bottom of the moving mechanism 6, the moving mechanism 6 is connected with the frame 7 through the guide rail 8, the moving mechanism 6 moves up and down along the guide rail 8, and the frame 7 and the guide rail 8 provide support and displacement for the moving mechanism 6 and the punch assembly.

[0033] The punch assembly includes a counterweight 16 and a punch 17, the punch 17 is installed at the bottom of the counterweight 16, an impact force signal receiving device (which can be a pressure sensor) is installed inside the punch 17, which is used to obtain the impact signal of the punch 17. The impact force signal receiving device is in communication connection with the computer, and the mechanical curve of the test piece is obtained based on the impact force information. Among them, the punch assembly is the impact of different angles at the same impact point.

[0034] The counterweight 16 is detachably connected with the moving mechanism 6, in this embodiment, the top of the counterweight 16 is connected with the bottom of the moving mechanism 6 through magnetic attraction, so as to realize the release and grabbing of the punch assembly.

[0035] The counterweight 16 is provided with a first limiter 9, and the guide rail 8 is provided with a second limiter 18, the second limiter 18 can move on the guide rail 8, and the second limiter 18 and the moving mechanism 6 are located on two parallel tracks on the guide rail 8, and the strokes do not affect each other. The first limiter 9 and the second limiter 18 are in communication connection with the computer, and the two are existing infrared limiting devices, which are triggered by shielding infrared rays. It can mark the zero position of the test.

[0036] The fixed assembly is provided with a liftable buffer device 5 on both sides for contacting the punch assembly, which can not only limit the end position of the impact stroke, but also control the impact energy of the punch 17, prevent overloading impact, and ensure the accuracy of test data. It can also prevent secondary impact phenomenon (the punch assembly is buffered by the buffer and will not bounce up again to repeat free fall) from interfering with the test data.

[0037] The definition of the impact angle of the application is the included angle between the vertical direction of the punch assembly and the extension direction of the impact point of the composite material.

[0038] The fixed platform 3 is a horizontal device, the bottom is fixed by screws, and the protractor 4 is installed on one side of the lower fixed plate 2, which is used to observe the angle change range. When the positions of the first clamping groove structure 11 and the second clamping groove structure 12 are determined, the fixed assembly and the fixed platform 3 are installed and positioned by cooperation of the screws and the threaded holes. When the position of the test sample is determined, the fixed platform 3 is installed and positioned by cooperation of the screws and the threaded holes. The screw is an M10 screw.

[0039] The application also provides a multi-angle low-speed impact test method for the inner surface of a composite material arc-shaped plate, which comprises the following steps: S1, the test sample is placed between the upper fixed plate 1 and the lower fixed plate 2, it is checked whether the test sample is tightly attached to the upper fixed plate 1 and the lower fixed plate 2, and it is checked whether the impact point exposed by the impact hollow groove 13 is aligned with the punch 17, so as to ensure that the punch 17 and the impact point position of the test sample are in the same straight line; S2, according to specific test requirements, the relative positions between the first clamping groove structure 11 and the second clamping groove structure 12 are adjusted, so that the impact angle meets the test requirements; S3, the punch assembly is controlled to descend, so that the punch 17 is tightly attached to the test sample, and the position is marked as a zero position; S4, when the punch 17 is located at the zero position, the limiters are adjusted, so that the first limiter 9 and the second limiter 18 are located on the same horizontal plane; S5, parameter values are set; the parameter values include impact energy and impact height; S6, the punch 17 is raised from the zero position to reach the parameter setting position; S7, start the program to perform the test, release the punch 17, the punch 17 contacts the test piece and collects signals, the signals are transmitted to the computer for analysis, and a curve of the relationship between load and time is output.

[0040] Furthermore, a fitting curve analysis was performed on the maximum loads and corresponding impact angles under several groups of impact angles obtained by the test method of the present invention, and the curve formula was obtained as follows: Where, a is the first constant, b is the second constant. The value is obtained by fitting the curve. When the coefficient of determination of the fitting curve is R 2 When it is close to 1, the punch mass and impact height known in the test method are consistent with the values ​​of a and b obtained from the fitting curve. Therefore, the maximum value prediction formula of the multi-angle impact load is further obtained: Where, m is the punch mass (the mass of the counterweight 16 and the punch 17); A is the impact angle; h is the impact height.

[0041] It can be seen that, in combination with the testing method of the present invention, a prediction formula for predicting the maximum load on the concave surface of the curved plate composite material under multi-angle impact can be obtained.

[0042] Example: Impact performance test of concave aramid composite material at different impact angles.

[0043] A method for testing the inner surface of a composite curved plate under multi-angle low-velocity impact, comprising the following steps: S1. Place the concave aramid composite specimen between the upper fixing plate 1 and the lower fixing plate 2. Check whether the specimen is tightly attached to the upper fixing plate 1 and the lower fixing plate 2. Secure the specimen with screws. Ensure that the impact point exposed by the impact on the hollow groove 13 is aligned with the punch 17. Ensure that the punch 17 and the impact point of the specimen are in the same straight line. S2. According to specific test requirements, adjust the relative position between the first slot structure 11 and the second slot structure 12 to rotate the specimen 60° around the impact point; S3. Control the punch assembly to descend so that the punch 17 is in close contact with the test piece and marks the zero point of the test; S4, when the punch 17 is at the zero position, adjust the limiter so that the first limiter 9 and the second limiter 18 are at the same horizontal plane; S5. Set the test parameter value and the impact energy to 25J; Impact energy E The kinetic energy formula is E =1 / 2mv 2 , wherein, v is the impact velocity; meanwhile, mgh =1 / 2 mv 2 =E , the impact energy can be calculated h ; S6, the impact energy setting is completed, the punch 17 is lifted from the zero position to a height meeting the energy requirement; S7, the program is started for testing, the punch 17 is released, the punch 17 contacts the test piece and collects signals, the signals are transmitted to the computer for analysis, and the load-time mutual relationship curve is output.

[0044] The test step is repeated, and the rotation angle of the test piece in step S2 around the impact point is changed to 75°, 90°, respectively.

[0045] Through the above test, it can be seen that the load-time curve is generated by the signal processing of the punch, and through the test, as the impact angle decreases, the maximum bearing load of the concave composite material test piece decreases, as shown in Figure 8 , the load is 6.92kN when the impact angle is 90°, the load is 6.35kN when the impact angle is 75°, and the load is 5.57kN when the impact angle is 60°.

[0046] The maximum load under the impact angles of 90°, 75° and 60° obtained by the maximum load prediction formula is 6.75kN, 6.47kN and 5.91kN, respectively, and the error is about 5%, so the prediction formula is relatively accurate.

[0047] It can be seen that the height of the punch 17 is controlled by the moving mechanism to obtain the impact potential energy of the punch 17, the impact load is applied to the test piece by releasing the punch 17, the impact force information in the process of the punch 17 impacting the test piece is obtained, then the load-time curve of the test piece is obtained based on the impact force information, and the impact mechanical properties of the composite material can be effectively evaluated, and the test basis for the qualification of the composite material is provided.

[0048] The embodiments of the present application are described in detail above, but the content described is only the preferred embodiments of the present application, and cannot be considered as limiting the scope of the present application. Any equivalent changes and improvements made within the scope of the present application should still belong to the scope of the present application.

Claims

1. A composite material curved plate inner surface multi-angle low-speed impact device, characterized by: The cam is secured to the bottom of the workbench and has a pivotal portion for securing the cam and securing the bottom surface of the workbench to the cam.

2. The composite material curved plate inner surface multi-angle low-speed impact device according to claim 1, characterized in that: The angle variation range of the test piece is 60° to 90°.

3. The composite material curved plate inner surface multi-angle low-speed impact device according to claim 1, characterized in that: The punch assembly includes a counterweight block and a punch. The punch is installed at the bottom of the counterweight block. An impact force signal receiving device is installed inside the punch to obtain the impact signal of the punch. The impact force signal receiving device is communicatively connected to a computer.

4. The composite material curved plate inner surface multi-angle low-speed impact device according to claim 3, characterized in that: The counterweight block is detachably connected to the moving mechanism to realize the release and grabbing of the punch assembly.

5. The composite material curved plate inner surface multi-angle low-speed impact device according to claim 3, characterized in that: A first limiter is provided on the counterweight block, and a second limiter is provided on the guide rail. The second limiter moves on the guide rail. The second limiter and the moving mechanism are located on two parallel tracks on the guide rail, and their travels do not affect each other. Both the first limiter and the second limiter are communicatively connected to the computer.

6. The composite material curved plate inner surface multi-angle low-speed impact device according to claim 1, characterized in that: Liftable buffer devices are provided on both sides of the fixing assembly for contacting the punch assembly.

7. The composite material curved plate inner surface multi-angle low-speed impact device according to claim 1, characterized in that: A protractor is installed on one side of the lower fixing plate.

8. A method for testing the inner surface of a composite curved plate by multi-angle low-velocity impact, implemented by the composite curved plate inner surface multi-angle low-velocity impact device according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Place the specimen between the upper and lower fixing plates. Place the specimen close to the upper and lower fixing plates. Align the impact point exposed by the hollow groove with the punch. Ensure that the punch and the impact point of the specimen are in the same straight line. S2. Adjust the relative position between the first slot structure and the second slot structure so that the impact angle meets the test requirements; S3. Control the punch assembly to descend so that the punch is in close contact with the test piece. The close contact position is marked as the zero position. S4. When the punch is at the zero position, adjust the limiter so that the first limiter and the second limiter are at the same horizontal plane; S5. Setting test parameter values, including impact energy and impact height; S6, the punch rises from the zero position to the parameter setting position; S7. Release the punch, the punch contacts the specimen and collects signals, which are transmitted to the computer for analysis and output as a curve of the relationship between load and time.

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