Waveform generation apparatus and method for simulating landing impact

Abstract

This invention relates to a waveform generation device and method for simulating landing impact. The device includes a base plate with a test frame mounted on it. An electromagnetic release hook and a laser displacement sensor are mounted on the top of the test frame. A housing is mounted on the top of the base plate, with a first inflation port at the bottom of the housing connected to an inflation solenoid valve. A rupture diaphragm or a sealing bottom cover is mounted on the bottom of the housing. A pressure sensor is housed inside the housing, with a sealing top cover at its top. A piston rod is slidably fitted onto the sealing top cover. A piston is located inside the housing and slidably fitted onto the inner wall of the housing at the bottom of the piston rod. A collision buffer layer abuts against an impact platform at the top of the piston rod. An overload sensor is mounted on the impact platform and slidably fitted onto the test frame. A support platform, flush with the lowest point of the impact platform's descent, is also mounted on the top of the base plate. The electromagnetic release hook, laser displacement sensor, inflation solenoid valve, pressure sensor, and overload sensor are all communicatively connected to a timing control system. This invention enables simulated landing impact tests on large-mass test products.

Description

Technical Field

[0001] This invention relates to the field of aerospace technology, and in particular to a waveform generation device and method for simulating landing impact. Background Technology

[0002] With the rapid development of reusable aerospace technology, many equipment products require ground-based landing impact tests during the development process to verify the functional performance and reliability of key products under real landing impact environments. This allows for the identification of design flaws before formal flight, thereby improving product quality. Furthermore, ground-based landing impact tests can determine the maximum permissible number of reuses for critical products.

[0003] As launch capacity requirements increase, the size of reusable rockets is also growing, leading to larger sizes and masses of their key components. However, existing simulated landing impact testing equipment can only conduct simulated landing impact tests on smaller and heavier components, but cannot perform such tests on larger and heavier components. This severely restricts the reusable design of key structural components for reusable rockets and the development of reusable aerospace technology.

[0004] Therefore, there is an urgent need for a waveform generator capable of simulating ground landing impacts on large-sized and high-mass test products. Summary of the Invention

[0005] The purpose of this invention is to provide a waveform generation device and method for simulating landing impact, thereby solving at least some of the technical problems existing in the prior art. For example, it solves the technical problem that the prior art cannot perform simulated landing impact tests on large-sized and high-mass test products. The mass of the large-sized and high-mass test product can be 6T or approximately 6T, and is not particularly limited herein.

[0006] To achieve the above objectives, the present invention provides the following solution: In a first aspect, the present invention provides a waveform generating device for simulating landing impact, comprising a base plate on which a test frame is mounted, and an electromagnetic release hook and a laser displacement sensor are mounted on the top of the test frame. The top of the base plate is vertically mounted with a shell that is open at both the bottom and top. A first inflation port is located at the bottom of the side wall of the shell and is connected to an inflation solenoid valve. A detachable diaphragm or sealing cap is mounted at the bottom of the shell. A pressure sensor is installed inside the shell, and a sealing cap is mounted on its top. A piston rod is vertically slidably fitted onto the sealing cap. A piston is mounted at the bottom of the piston rod and is located inside the shell, slidingly fitted against the inner side wall of the shell. A collision buffer layer is mounted on the top of the piston rod, and an impact platform is abutted against the top of the collision buffer layer. An overload sensor is mounted on the impact platform and is vertically slidably fitted against the test frame. An electromagnetic release hook is located directly above the impact platform, and the measuring end of the laser displacement sensor is correspondingly positioned with respect to the impact platform. A support platform is also installed at the top of the base plate, and the top of the support platform is flush with the lowest position of the bottom of the impact platform when it falls; the electromagnetic release hook, the laser displacement sensor, the air-filling solenoid valve, the pressure sensor and the overload sensor are all communicatively connected to the timing control system.

[0007] According to one embodiment of the present invention, a second air inlet is further provided at the bottom of the side wall of the housing, and the second air inlet is connected to a compensation solenoid valve, which is communicatively connected to the timing control system.

[0008] According to one embodiment of the present invention, the rupture diaphragm is an inverted arch rupture diaphragm.

[0009] According to one embodiment of the present invention, the impact buffer layer is a structural foam material.

[0010] According to one embodiment of the present invention, the test frame is equipped with a guide rod in the vertical direction, and the impact table is limited and slidably engaged with the guide rod. The impact table is limited and slidably engaged with the test frame in the vertical direction through the guide rod.

[0011] According to one embodiment of the present invention, the piston rod extends vertically and is slidably fitted at the center of the sealing top cover, and a first dustproof sealing ring is provided at the slidable fit between the piston rod and the sealing top cover.

[0012] According to one embodiment of the present invention, a second dustproof sealing ring is provided at the sliding fit between the piston and the inner sidewall of the housing.

[0013] Secondly, the present invention provides a design method for a waveform generator for simulating landing impact, comprising the waveform generator for simulating landing impact as described in any one of the above-mentioned contents, including the following steps: S1. Design and determine the characteristic parameters of the shell by combining theoretical and numerical calculations; S2. Design and determine the material, cross-sectional area, and thickness of the collision buffer layer by considering the impact effect of the effective load on the collision buffer layer; S3. Calculate and determine the displacement height of the product to be tested by the electromagnetic release hook by the impact overload time history. S4. Design and determine the characteristic parameters of the impact table through simulation calculations; S5. Determine the height of the support platform by the lowest point where the impact platform falls during the actual impact process; S6. Select the appropriate rupture diaphragm based on the maximum pressure value measured by the pressure sensor.

[0014] According to one embodiment of the present invention, the method of combining theory and numerical calculation includes: determining the cavity characteristic parameters of the shell by means of the adiabatic compression theory of a closed cavity and finite element numerical simulation calculation according to the impact technical requirements; wherein the finite element numerical simulation calculation is performed by means of numerical simulation analysis method.

[0015] Thirdly, the present invention provides a method of using a waveform generating device for simulating landing impact, comprising the steps of using the waveform generating device for simulating landing impact as described in any one of the above descriptions, including the following steps: a. Install a sealed bottom cover at the bottom of the casing; b. Connect a mass block with the same mass as the product to be tested to the impact table, and hoist both of them together onto the electromagnetic release hook; c. Open the inflation solenoid valve and use a gas compressor or high-pressure gas cylinder to inflate the housing until the housing reaches the design pressure value, then close the inflation solenoid valve. d. Unlock the electromagnetic release hook to allow the mass block and the impact platform to fall, in order to conduct preliminary debugging of the simulated landing impact test; wherein, the preliminary debugging of the simulated landing impact test includes: comparing the difference between the actual impact pulse width and amplitude change curve and the theoretical impact pulse width and amplitude change curve according to the overload time history measured by the overload sensor during the entire impact process, and adjusting the opening and closing time of the inflation solenoid valve according to the comparison results until the actual impact pulse width and amplitude fully meet the technical requirements; e. Replace the mass block with the product to be tested, and hoist the product to be tested and the impact table together onto the electromagnetic release hook, while replacing the sealing bottom cover with a bursting diaphragm; f. Re-unlock the electromagnetic release hook to conduct a formal simulated landing impact test.

[0016] Beneficial effects This invention has at least the following technical effects: This invention, through its waveform generation device and design method, enables the realization of the required overload time history of the sawtooth waveform with a rear peak. Furthermore, this invention can, but is not limited to, perform simulated landing impact tests on large-sized, high-mass test products with a peak acceleration of 4g and a mass of 6T or approximately 6T, using a sawtooth waveform with a pulse width of approximately 130ms. This simulation can be easily adjusted according to actual working conditions, perfectly solving the shortcomings of existing technologies that cannot simulate landing impact tests on large-sized, high-mass test products. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention with the rupture diaphragm installed; Figure 2 for Figure 1 A schematic diagram of the overall structure from another angle; Figure 3 for Figure 1 A cross-sectional view; Figure 4 for Figure 3 A magnified view of a section at point A in the middle; Figure 5 This is a schematic diagram of the overall structure of the bursting diaphragm in this invention; Figure 6 This is a schematic diagram of the overall structure of the sealing bottom cover in this invention; Figure 7 This is a schematic diagram comparing simulation calculation results in the design method of the present invention; Figure 8 This is a schematic diagram of the overload time history during the first drop in the method of use of the present invention; Figure 9 This is a schematic diagram of the descent time of the impact platform during the first descent in the method of use of the present invention; Figure 10 This is a schematic diagram of the pressure-time history inside the shell during the second descent in the method of use of the present invention; Figure 11 This is a schematic diagram illustrating the impact overload time history of measuring points at different locations during the first drop in the method of use of this invention; Figure 12 This is a schematic diagram comparing the overload time history at different positions during the second drop in the method of use of the present invention.

[0019] Explanation of reference numerals in the attached figures: 1. Base plate; 2. Test frame; 3. Electromagnetic release hook; 4. Guide rod; 5. Impact table; 6. Collision buffer layer; 7. Support platform; 8. Piston rod; 9. Sealing top cover; 10. Piston; 11. Shell; 12. First air inlet; 13. Second air inlet; 14. Bursting diaphragm; 15. First dustproof sealing ring; 16. Second dustproof sealing ring; 17. Sealing bottom cover. Detailed Implementation

[0020] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present invention and to exemplify the principles of the present invention, and are not configured to limit the present invention. In addition, the structural components in the drawings are not necessarily drawn to scale. For example, the dimensions of some structural components or regions in the drawings may be enlarged for other structural components or regions to aid in the understanding of the embodiments of the present invention.

[0021] The directional terms used in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of the embodiments of the present invention. In the description of the present invention, it should be noted that, unless otherwise stated, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0022] Furthermore, the terms "comprising," "including," "having," or any other variations thereof are intended to cover non-exclusive inclusion, such that a structure or component that includes a list of elements includes not only those elements but also other structural elements that are not expressly listed or inherent to the structure or component. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the article or apparatus that includes the element.

[0023] Spatial relation terms such as "below," "under," "under," "low," "above," "on," and "high" are used for descriptive convenience to explain the positioning of one element relative to a second element, indicating that these terms are intended to cover different orientations of the device, in addition to those different from those shown in the figure. Furthermore, phrases such as "one element on / below another element" can indicate that two elements are in direct contact, or that there are other elements between the two elements. In addition, terms such as "first" and "second" are also used to describe individual elements, areas, parts, etc., without specifically indicating order or sequence, and should not be considered restrictive. Similar terms are used throughout the description to represent similar elements.

[0024] It will be apparent to those skilled in the art that the present invention can be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention.

[0025] In the following embodiments, there may be descriptions such as "this device". It should be understood that "this device" refers to a waveform generating device for simulating landing impact provided by the present invention.

[0026] Firstly, such as Figures 1-6 As shown, this embodiment provides a waveform generator for simulating landing impact. The device includes at least a base plate 1, with a test frame 2 fixedly mounted on the top of the base plate 1. An electromagnetic release hook 3 and a laser displacement sensor (not shown in the figure) are mounted on the top of the test frame 2.

[0027] In this embodiment, the electromagnetic release hook 3 can be an electromagnetic release hook with a load capacity of 10T or approximately 10T, and is not particularly limited here.

[0028] In this embodiment, as Figure 3 and Figure 4 As shown, a shell 11 with an open structure at both the bottom and top and capable of communicating with the outside is fixedly installed at the top of the base plate 1 in the vertical direction (that is, in the direction of gravity, the same below). Preferably, a first air inlet 12 is provided at the bottom of the side wall of the shell 11, and the first air inlet 12 is connected to an air inflation solenoid valve (not shown in the figure).

[0029] In this embodiment, the housing 11 can be a cylindrical structure, and there is no particular limitation.

[0030] Specifically, in one embodiment of the present invention, the first inflation port 12 may be connected to and communicate with a first pipeline (not shown in the figure), and an inflation solenoid valve may be provided on the first pipeline and be able to control the opening and closing of the first pipeline. The end of the first pipeline away from the first inflation port 12 may be connected to and communicate with a gas compressor or a high-pressure gas cylinder for inflation of the interior of the housing 11.

[0031] In this embodiment, to ensure smooth communication between the bottom of the housing 11 and the outside world, such as... Figure 4 As shown, a pad can be fixedly installed at the bottom of the housing 11, and the pad is fixedly installed at the top of the base plate 1, that is, the housing 11 can be fixedly installed at the top of the base plate 1 by means of the pad.

[0032] like Figure 4 As shown, a rupture diaphragm 14 is detachably installed at the bottom of the housing 11 (see reference). Figure 5 ) or sealed bottom cover 17 (see reference) Figure 6 A pressure sensor (not shown in the figure) is installed inside the housing 11, and a sealing top cover 9 is fixedly installed on the top of the housing 11. A piston rod 8 is vertically slidably fitted onto the sealing top cover 9, and a piston 10 is fixedly installed at the bottom end of the piston rod 8. The piston 10 is entirely located inside the housing 11 (i.e., the piston 10 is entirely located below the sealing top cover 9), and the sidewall of the piston 10 contacts and slides against the inner sidewall of the housing 11.

[0033] In this embodiment, as Figure 5 and Figure 6 As shown, the sealing bottom cover 17 and the rupture diaphragm 14 have the same shape. Therefore, regardless of whether the rupture diaphragm 14 or the sealing bottom cover 17 is installed at the bottom of the housing 11, the internal volume of the housing 11 can be kept consistent.

[0034] In this embodiment, both the piston rod 8 and the piston 10 can be cylindrical structures, and no particular limitation is made here.

[0035] In this embodiment, the rupture diaphragm 14 and / or the sealing bottom cover 17 can be installed at the bottom of the housing 11 by means of flange connection, and there is no particular limitation.

[0036] In this embodiment, as Figure 2 and Figure 4 As shown, a collision buffer layer 6 is installed at the top of the piston rod 8, and the top of the collision buffer layer 6 abuts against the impact table 5. An overload sensor (not shown in the figure) is installed on the impact table 5, and the impact table 5 and the test frame 2 can be limited and slidably engaged in the vertical direction. Among them, the electromagnetic release hook 3 is located directly above the impact table 5, and the laser displacement sensor is located above the impact table 5, with the measuring end of the laser displacement sensor corresponding to the top of the impact table 5.

[0037] In this embodiment, the top of the impact table 5 can be used to mount the product to be tested or a mass block with the same mass as the product to be tested.

[0038] In this embodiment, by setting the collision buffer layer 6, the high-frequency energy generated during the rigid collision between the bottom end of the impact platform 5 and the top end of the piston rod 8 can be absorbed and effectively eliminated, and the high-frequency energy can be converted into the elastic strain energy of the elastic material. This ensures that the impact overload increases slowly and linearly with the change of displacement, so as to prevent the impact overload from exceeding the tolerance.

[0039] It should be understood that, Figure 4 The state shown is that the bottom end of the housing 11 is equipped with a bursting diaphragm 14, not that the bottom end of the housing 11 is equipped with a sealing bottom cover 17.

[0040] like Figure 1 and Figure 2 As shown, a support platform 7 is also installed at the top of the base plate 1. The top of the support platform 7 is flush with the lowest point (i.e., the peak point) that the bottom of the impact platform 5 can fall to. Alternatively, the top of the support platform 7 can be slightly lower than the lowest point that the bottom of the impact platform 5 can fall to, for example, it can be 1cm-2cm lower, without any particular limitation.

[0041] In this embodiment, as Figure 1 As shown, the number of support platforms 7 can be four, and they are evenly distributed on the base plate 1 in sequence, without any special limitation.

[0042] It should be understood that the lowest position of the impact platform 5 is when the air pressure inside the shell 11 is at its maximum value.

[0043] In this embodiment, the electromagnetic release hook 3, the laser displacement sensor, the inflation solenoid valve, the pressure sensor, and the overload sensor are all communicatively connected to the timing control system (not shown in the figure).

[0044] In the above, the pressure sensor can be used to accurately and in real-time measure the inflation pressure inside the housing 11, thereby obtaining the time history curve of the gas pressure inside the housing 11 during the impact process; the overload sensor can be used to accurately and in real-time measure the effective load overload time history of the center of mass of the product or mass block under test during the impact process; the laser displacement sensor can be used to accurately and in real-time measure the displacement time history of the impact table 5 during the hoisting process and during the descent process. The timing control system can receive signals from the electromagnetic release hook 3, the laser displacement sensor, the inflation solenoid valve, the pressure sensor, and the overload sensor respectively, and control and adjust each of them. For example, the timing control system can accurately control the unlocking or locking of the electromagnetic release hook 3 to accurately control the initial zero point of the fall of the product or mass block under test, that is, the initial zero point of the fall of the impact table 5.

[0045] Furthermore, in order to quickly compensate for the air pressure inside the housing 11 (i.e., the insufficient air pressure section) during the impact test, and thus accurately adjust the air pressure inside the housing 11 to make the impact test results more accurate, in this embodiment, a second air inlet 13 is also provided on the bottom end of the side wall of the housing 11. The second air inlet 13 is connected to a compensation solenoid valve, and the compensation solenoid valve is communicatively connected to the timing control system, that is, the timing control system can also control and adjust the compensation solenoid valve.

[0046] Preferably, in this embodiment, both the inflation solenoid valve and the compensation solenoid valve can be quick-opening and quick-closing solenoid valves.

[0047] Specifically, in one embodiment of the present invention, the second inflation port 13 may be connected to and communicate with a second pipeline (not shown in the figure), and a compensation solenoid valve may be provided on the second pipeline and be able to control the on / off state of the second pipeline. The end of the second pipeline away from the second inflation port 13 may be connected to and communicate with a gas compressor or a high-pressure gas cylinder for compensating inflation of the interior of the housing 11.

[0048] In this embodiment, the overload-time function curve can be determined based on actual measurements (such as...). Figure 7 and Figure 8 As shown), the compensation solenoid valve performs real-time compensation inflation on the interior of the housing 11. For example, when the actual curve exceeds the lower limit of the standard tolerance of the theoretical curve, the timing control system will control the compensation solenoid valve to open at that moment (or near that moment), thereby performing real-time compensation inflation on the interior of the housing 11 at that moment (or near that moment).

[0049] Preferably, in this embodiment, the rupture diaphragm 14 can be an inverted arch rupture diaphragm, which is not particularly limited here.

[0050] In this embodiment, since the sealing bottom cover 17 and the rupture diaphragm 14 have the same shape, when the rupture diaphragm 14 is an inverted arch rupture diaphragm, the selected sealing bottom cover 17 will also have the same shape as the inverted arch rupture diaphragm. Therefore, it should be understood that whether the sealing bottom cover 17 is installed at the bottom of the housing 11 or the rupture diaphragm 14 (i.e., the inverted arch rupture diaphragm) is installed at the bottom of the housing 11, the internal volume of the housing 11 can remain consistent.

[0051] Preferably, in this embodiment, the collision buffer layer 6 can be a structural foam material, such as polymethacrylimide (PMI) foam, which has excellent specific stiffness, specific strength, and mechanical properties such as compression, tension, shear, and bending. No particular limitation is made here.

[0052] Specifically, such as Figure 1 and Figure 2 As shown, a guide rod 4 is installed vertically on the test frame 2. The guide rod 4 passes through the impact table 5, and the impact table 5 can slide and be limited by the guide rod 4. That is, the impact table 5 can slide and be limited by the test frame 2 in the vertical direction through the guide rod 4.

[0053] More specifically, there can be four guide rods 4, which are evenly distributed between the test frame 2 and the base plate 1, thereby improving the stability of the impact table 5 during the descent. For example, the top ends of the four guide rods 4 can be fixedly connected to the top end of the test frame 2, and the bottom ends of the four guide rods 4 can be fixedly connected to the top end of the base plate 1, without any particular limitation.

[0054] It should be understood that for a large mass product or mass block, the friction between the guide rod 4 and the impact table 5 is negligible and will not affect the results of the impact test.

[0055] Specifically, such as Figure 4 As shown, the piston rod 8 can slide vertically through and be limited in a sliding fit at the center of the sealing top cover 9.

[0056] Furthermore, in order to improve the sealing performance of the housing 11 and thus prevent air leakage, thereby ensuring the accuracy of the impact test results, such as... Figure 4 As shown, a first dustproof sealing ring 15 is provided at the limiting sliding fit between the piston rod 8 and the sealing top cover 9; a second dustproof sealing ring 16 is provided at the sliding fit between the piston 10 and the inner side wall of the housing 11. The first dustproof sealing ring 15 can be fixedly connected to the sealing top cover 9, and the second dustproof sealing ring 16 can be fixedly connected to the piston 10.

[0057] In this embodiment, unless otherwise specified, all of the above-described fixing connection methods can be one or more of the bolted connection, welded connection or adhesive connection known in the art, and are not particularly limited herein.

[0058] Secondly, referring to Figures 7-12 This embodiment also provides a design method for a waveform generator for simulating landing impact. This design method includes the waveform generator for simulating landing impact described in any one of the above-mentioned embodiments, and includes at least the following steps: S1. Design and determine the specific characteristic parameters of the shell 11 by combining theoretical and numerical calculations.

[0059] In step S1, the method of combining theory and numerical calculation includes: determining the cavity characteristic parameters of the shell 11 by means of the adiabatic compression theory of the sealed cavity and finite element numerical simulation calculation according to the impact technology requirements; wherein, the finite element numerical simulation calculation is performed by means of numerical simulation analysis method.

[0060] In this embodiment, the numerical simulation analysis method can be performed by any numerical simulation analysis software known in the art capable of performing numerical simulation analysis.

[0061] In step S1, the material strength and specific dimensions of the shell 11 can be determined based on the maximum pressure inside the shell 11 during the impact test calculated by combining theoretical and numerical calculations, thereby ensuring the safety margin of the structural material during the impact test.

[0062] S2. The impact effect of the effective load on the collision buffer layer 6 is designed, and the material, cross-sectional area, and laying thickness of the collision buffer layer 6 are determined. In actual use, a specific high-rigidity foam material is used to achieve the buffering function.

[0063] S3. Determine the selection of the inflation solenoid valve and the compensation solenoid valve. Specifically, since both the product under test and the mass block have large masses, and the buffer overload requires precise control, a quick-opening and quick-closing solenoid valve is selected to achieve rapid and precise adjustment of the gas pressure.

[0064] S4. Calculate and determine the displacement height of the product to be tested by the electromagnetic release hook 3 through impact overload time history calculation.

[0065] S5. Design and determine the characteristic parameters of the impact table 5 through simulation calculations to ensure structural safety and stiffness characteristics during the impact test.

[0066] S6. The height of the support platform 7 is determined by the lowest position of the impact platform 5 during the actual impact test, so as to seamlessly support the impact platform 5 when the rupture diaphragm 14 ruptures, thereby achieving safety protection for the device.

[0067] In steps S5 and S6, based on the preliminary design results, the sealing bottom cover 17 is first installed at the bottom of the housing 11, and a mass block of the same mass as the product under test is subjected to free fall to simulate the initial rise edge overload time history of the mass block in a completely sealed and non-venting state of the housing 11. During this process, the pressure sensor monitors the initial inflation pressure inside the housing 11 in real time, and the timing control system can precisely control the inflation solenoid valve and the compensation solenoid valve to accurately regulate the gas pressure inside the housing 11. Through the above, parameters such as the initial inflation pressure, compensation pressure, and hoisting displacement height can be adjusted to ensure that the rise edge overload time history meets the technical requirements.

[0068] S7. Select the appropriate rupture diaphragm 14 based on the maximum pressure value measured by the pressure sensor.

[0069] In step S7, after obtaining the rise-edge overload time history after meeting the design specifications, the sealing bottom cover 17 at the bottom of the housing 11 is replaced with a burst diaphragm 14. Specifically, a suitable anti-arched burst diaphragm needs to be replaced based on the maximum pressure value measured by the pressure sensor.

[0070] In this embodiment, the device and the above-described design method can achieve the overload time history of the back-peak sawtooth waveform required by the design. Simultaneously, this device includes, but is not limited to, the ability to perform simulated landing impact tests on large-sized, high-mass test products or mass blocks with a peak acceleration of 4g and a mass of 6T or approximately 6T, using a back-peak sawtooth waveform with a pulse width of approximately 130ms. It can be easily adjusted according to actual working conditions, perfectly solving the shortcomings of existing technologies that cannot simulate landing impact tests on large-sized and high-mass test products. This will not restrict the reuse design of key structural components for reusable rockets or the development of reusable aerospace technology.

[0071] Thirdly, referring to Figures 7-12 This embodiment also provides a method of using a waveform generator for simulating landing impact, which includes the steps of using the waveform generator for simulating landing impact described in any one of the above descriptions. The method of use includes at least the following steps: a. Assemble the device and install the sealing cover 17 at the bottom of the housing 11. At the same time, test and debug each sensor in the device (i.e., laser displacement sensor, pressure sensor and overload sensor) to ensure that all three are in normal working condition.

[0072] In step a, the inflation solenoid valve, compensation solenoid valve and electromagnetic release hook 3 also need to be tested and adjusted to ensure that all three are in normal working condition.

[0073] b. Connect a mass block with the same mass as the product to be tested to the impact table 5 (that is, install a mass block with the same mass as the product to be tested on the top of the impact table 5), and hoist both of them onto the electromagnetic release hook 3.

[0074] In step b, there are no particular restrictions on how the mass block is installed on the top of the impact table 5; for example, the two can be connected to each other by high-strength bolts.

[0075] In step b, the mass block and the impact table 5 can be hoisted together onto the electromagnetic release hook 3 using a crane. During the hoisting process, the laser displacement sensor will measure the lifting height of the impact table 5 in real time and transmit the measured height data signal to the timing control system in real time.

[0076] c. The timing control system will open the inflation solenoid valve and use a gas compressor or high-pressure gas cylinder to inflate the housing 11. Once the design pressure value is reached inside the housing 11, the timing control system will close the inflation solenoid valve.

[0077] In step c, the pressure sensor monitors the pressure value inside the housing 11 in real time. When the internal pressure value of the housing 11 reaches the design pressure value, the pressure sensor transmits a signal to the timing control system. Upon receiving the signal, the timing control system will cause the inflation solenoid valve to close automatically momentarily.

[0078] d. The timing control system will unlock the electromagnetic release hook 3, causing the mass block and the impact platform 5 to fall (free fall). At this time, the bottom of the impact platform 5 will contact the collision buffer layer 6 as it falls, and continue to fall after contacting the collision buffer layer 6, thereby compressing the gas inside the shell 11 and gradually increasing the air pressure inside the shell 11 for preliminary debugging of the simulated landing impact test (this process can also be understood as the first fall). It should be understood that during this process, when the falling speed of the impact platform 5 and the mass block installed on it is zero, the air pressure inside the shell 11 will reach its maximum value.

[0079] In step d, the preliminary debugging of the simulated landing impact test also includes at least the following: based on the overload time history measured by the overload sensor during the entire impact process, comparing the difference between the actual impact pulse width and amplitude change curve and the theoretical impact pulse width and amplitude change curve, and adjusting the opening and closing time of the inflation solenoid valve according to the comparison results until the actual impact pulse width and amplitude fully meet the technical requirements.

[0080] e. After completing step d, while ensuring that other states remain unchanged, replace the mass block on the impact table 5 with the product to be tested, and hoist the product to be tested and the impact table 5 together onto the electromagnetic release hook 3 using a crane. At the same time, replace the sealing bottom cover 17 with a bursting diaphragm 14 of suitable specifications (preferably an anti-arched bursting diaphragm).

[0081] f. The timing control system will unlock the electromagnetic release hook 3 again to conduct a formal simulated landing impact test (this process can also be understood as a second fall), thereby verifying the functional performance and product reliability of the product under test.

[0082] It should be understood that, similarly, in step f, when the falling speed of the impact table 5 and the product under test mounted on it is zero, the air pressure inside the housing 11 will reach its maximum value, which is exactly the rated burst pressure value of the rupture diaphragm 14. At this time, the rupture diaphragm 14 will burst, and the air pressure inside the housing 11 will be released instantaneously, meaning that the reverse pressure it provides will also instantly decrease to zero, thus obtaining a sawtooth waveform that meets the standard tolerance requirements. Specifically, when the rupture diaphragm 14 bursts (i.e., when the falling speed of the impact table 5 is exactly zero), the height of the bottom of the impact table 5 will be exactly level with the top of the support table 7. Therefore, the bottom of the impact table 5 will just abut against the top of the support table 7, seamlessly connecting the support table 7 to support the impact table 5.

[0083] In this embodiment, step f can be performed multiple times to better verify the functional performance and reliability of the product under test, and also to verify the maximum number of times the product under test can be reused.

[0084] It should be understood that the above-described embodiments or examples of the present invention can be combined with each other and have corresponding technical effects.

[0085] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A waveform generator for simulating landing impact, characterized in that, Includes a base plate (1), on which a test frame (2) is mounted, and an electromagnetic release hook (3) and a laser displacement sensor are mounted on the top of the test frame (2); The top of the base plate (1) is vertically mounted with a housing (11) that has an open structure at both the bottom and top. The bottom of the side wall of the housing (11) has a first inflation port (12) connected to an inflation solenoid valve. The bottom of the housing (11) is detachably mounted with a bursting diaphragm (14) or a sealing bottom cover (17). A pressure sensor is installed inside the housing (11) and a sealing top cover (9) is installed at its top. The sealing top cover (9) is vertically limited and slidably fitted with a piston rod (8). The piston rod (8) A piston (10) is installed at the bottom end. The piston (10) is located inside the housing (11) and slides in cooperation with the inner wall of the housing (11). A collision buffer layer (6) is installed at the top end of the piston rod (8). An impact table (5) is abutted at the top end of the collision buffer layer (6). An overload sensor is installed on the impact table (5) and it slides in a vertical direction with the test frame (2). The electromagnetic release hook (3) is located directly above the impact table (5). The measuring end of the laser displacement sensor is set correspondingly to the impact table (5). The top of the base plate (1) is also equipped with a support platform (7), the top of the support platform (7) is flush with the lowest position of the bottom of the impact platform (5) when it falls; the electromagnetic release hook (3), the laser displacement sensor, the air-filling solenoid valve, the pressure sensor and the overload sensor are all connected to the timing control system.

2. The waveform generating device for simulating landing impact according to claim 1, characterized in that, The bottom of the side wall of the housing (11) is also provided with a second air inlet (13), which is connected to a compensation solenoid valve. The compensation solenoid valve is communicatively connected to the timing control system.

3. The waveform generating device for simulating landing impact according to claim 1, characterized in that, The rupture diaphragm (14) is an inverted arch rupture diaphragm.

4. The waveform generating device for simulating landing impact according to claim 1, characterized in that, The collision buffer layer (6) is a structural foam material.

5. The waveform generating device for simulating landing impact according to claim 1, characterized in that, The test frame (2) is equipped with a guide rod (4) in the vertical direction, and the impact table (5) is in a limiting sliding fit with the guide rod (4).

6. The waveform generating device for simulating landing impact according to claim 1, characterized in that, The piston rod (8) passes through and is slidably fitted in the center of the sealing top cover (9) in the vertical direction, and a first dustproof sealing ring (15) is provided at the slidable fit between the piston rod (8) and the sealing top cover (9).

7. The waveform generating device for simulating landing impact according to claim 1, characterized in that, A second dustproof sealing ring (16) is provided at the sliding fit between the piston (10) and the inner wall of the housing (11).

8. The design method of the waveform generator for simulating landing impact according to any one of claims 1-7, characterized in that, Includes the following steps: S1. The characteristic parameters of the shell (11) are designed and determined by combining theoretical and numerical calculations; S2. Design and determine the material, cross-sectional area and thickness of the impact buffer layer (6) by measuring the impact effect of the effective load on the impact buffer layer (6); S3. Calculate and determine the displacement height of the product to be tested by the electromagnetic release hook (3) by the impact overload time history; S4. Design and determine the characteristic parameters of the impact table (5) through simulation calculation; S5. Determine the height of the support platform (7) by the lowest position of the impact platform (5) during the actual impact process; S6. Select the appropriate rupture diaphragm (14) based on the maximum pressure value measured by the pressure sensor.

9. The design method of the waveform generator for simulating landing impact according to claim 8, characterized in that, The method of combining theory and numerical calculation includes: determining the cavity characteristic parameters of the shell (11) by means of the closed cavity adiabatic compression theory and finite element numerical simulation calculation according to the impact technology requirements; wherein the finite element numerical simulation calculation is performed by means of numerical simulation analysis method.

10. The method of using the waveform generator for simulating landing impact according to any one of claims 1-7, characterized in that, Includes the following steps: a. Install a sealing bottom cover (17) at the bottom of the housing (11). b. Connect a mass block with the same mass as the product to be tested to the impact table (5), and hoist them together onto the electromagnetic release hook (3). c. Open the inflation solenoid valve and use a gas compressor or high-pressure gas cylinder to inflate the housing (11) until the housing (11) reaches the design pressure value, then close the inflation solenoid valve. d. Unlock the electromagnetic release hook (3) to allow the mass block and the impact table (5) to fall, so as to conduct preliminary debugging of the simulated landing impact test; wherein, the preliminary debugging of the simulated landing impact test includes: according to the overload time history measured by the overload sensor during the entire impact process, comparing the difference between the actual impact pulse width and amplitude change curve and the theoretical impact pulse width and amplitude change curve, and adjusting the opening and closing time of the inflation solenoid valve according to the comparison results until the actual impact pulse width and amplitude fully meet the technical requirements; e. Replace the mass block with the product to be tested, and hoist the product to be tested and the impact table (5) together on the electromagnetic release hook (3), while replacing the sealing bottom cover (17) with the bursting diaphragm (14). f. Re-unlock the electromagnetic release hook (3) to conduct a formal simulated landing impact test.

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