Solid propellant biaxial tensile testing apparatus and method

Abstract

The application discloses a solid propellant biaxial tensile testing device and a testing method, and relates to the technical field of solid propellant mechanical property testing. The device comprises a vertical support, a mounting plate, sliding rails, fixed pulleys, movable pulleys, moving clamps, a loading mechanism and ropes. The mounting plate is fixedly installed on the vertical support. Four sliding rails are installed on the mounting plate. The four sliding rails are distributed at equal angles in a cross shape. One moving clamp is slidably arranged on each sliding rail. One end of the moving clamp is used for connecting a solid propellant biaxial tensile sample. The other end of the moving clamp is provided with a plurality of movable pulleys. A plurality of fixed pulleys are arranged on the outer sides of the sliding rails. The fixed pulleys are installed on the mounting plate. The loading mechanism is provided with a plurality of loading mechanism movable pulleys. The ropes are used for connecting the loading mechanism movable pulleys, the fixed pulleys and the movable pulleys, and suspending the loading mechanism below the mounting plate. The application can realize biaxial tensile testing of solid propellant creep load under different loading ratios. The structure is simple, small and low in economic cost.

Description

Technical Field

[0001] This invention relates to the field of solid propellant mechanical property testing technology, and in particular to a biaxial tensile testing device and method for solid propellants. Background Technology

[0002] Solid rocket motors, with their simple structure, high reliability, and ease of long-term storage, are widely used in military and aerospace engineering. The solid propellant grain is both the energy source and a key component affecting the structural integrity of the solid rocket motor. Currently, most tactical missiles launched domestically and internationally use propellants that have undergone varying periods of storage and aging. During storage, due to the long-term effects of its own weight and environmental factors, the solid propellant in solid rocket motors is under complex stress conditions driven by creep, leading to accumulated damage and the formation of microcracks. Therefore, to effectively analyze the structural integrity of solid propellants, it is necessary to study their mechanical properties under biaxial tensile stress.

[0003] Currently, most existing experimental methods for studying the biaxial tensile mechanical behavior of solid propellants employ a 1:1 ratio loading, meaning the output force of the testing system is the same as the tensile force of the specimen. These methods are also expensive and bulky. Therefore, there is an urgent need to design an economical and efficient biaxial tensile testing device to obtain the biaxial tensile mechanical properties of solid propellants under creep loads. Summary of the Invention

[0004] The purpose of this invention is to provide a biaxial tensile testing device and method for solid propellants to solve the problems existing in the prior art. It can realize biaxial tensile testing of solid propellant creep load under different loading ratios, and has a simple and compact structure with low economic cost.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] This invention provides a solid propellant biaxial tensile testing device, comprising a vertical support, a mounting plate, slide rails, fixed pulleys, movable pulleys, a movable clamp, a loading mechanism, and a rope. The mounting plate is fixedly mounted on the vertical support. Four slide rails are mounted on the mounting plate, arranged in a cross shape at equal angles. A movable clamp slides on each slide rail. One end of the movable clamp near the center of the cross of the four slide rails is used to connect the solid propellant biaxial tensile specimen, and the other end is equipped with several movable pulleys. Several fixed pulleys are provided on the outer side of the end of each slide rail away from the center of the cross. The fixed pulleys are mounted on the mounting plate. The loading mechanism has several loading mechanism movable pulleys. The rope connects the loading mechanism movable pulleys, the fixed pulleys, and the movable pulleys, and suspends the loading mechanism below the mounting plate.

[0007] In one embodiment, the system further includes a temperature and humidity control box, wherein both the mounting plate and the loading mechanism are disposed within the temperature and humidity control box.

[0008] In one embodiment, the loading mechanism includes a T-shaped loading head, a tray, and a plurality of loading discs. The loading mechanism's movable pulley is mounted on the T-shaped loading head, the tray is fixed to the lower end of the T-shaped loading head, and the loading discs are used to be placed on the tray.

[0009] In one embodiment, the mounting plate is an octagonal flat plate.

[0010] In one embodiment, the octagonal plate has a cross-shaped groove in the middle, and slide rail fixing holes are evenly distributed in the cross-shaped groove for fixing the slide rail by screws.

[0011] In one embodiment, the mounting plate is provided with a fixed pulley fixing hole, the fixed pulley is installed and fixed in the fixed pulley fixing hole, and a fixed pulley pad is provided between the fixed pulley and the mounting plate.

[0012] In one embodiment, the outer surface of the octagonal plate corresponding to the end of each slide rail away from the center of the cross is provided with a plate fixing hole. The plate fixing hole is used to connect a plate fixing shaft, and the plate fixing shaft is fixed to the vertical bracket by a pin.

[0013] In one embodiment, the movable clamp includes a movable block and a propellant clamp. The movable block is slidably disposed on the slide rail, and the propellant clamp is fixedly installed on the movable block and close to the cross center of the slide rail. A plurality of movable pulleys are installed at the end of the movable block away from the cross center, and a movable pulley pad is provided between the movable pulleys and the movable block.

[0014] In one embodiment, the slide rail has an I-shaped cross-section, and the moving block has an I-shaped slide track that mates with the I-shaped slide rail; the propellant clamp is fixed to the moving block by clamp screws.

[0015] This invention also provides a method for biaxial tensile testing of solid propellants, based on the aforementioned biaxial tensile testing apparatus for solid propellants, comprising the following steps:

[0016] The solid propellant biaxial tensile specimen is connected to the four movable clamps. The loading force of the loading mechanism is set, the loading ratio is determined, and the movable pulley, fixed pulley, and loading mechanism are connected by the rope. The loading mechanism is suspended below the mounting plate for biaxial tensile testing.

[0017] The present invention achieves the following technical effects compared to the prior art:

[0018] This invention allows for the construction of different pulley-fixed pulley combinations by changing the positions of the rope within the moving pulley, fixed pulley, and moving pulley of the loading mechanism. This enables biaxial tensile loading with different load ratios. Combined with the loading mechanism, it can complete biaxial tensile performance tests of solid propellants under different loads. The structure is simple, compact, and economical. Attached Figure Description

[0019] 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.

[0020] Figure 1 This is a schematic diagram of the structure of the solid propellant biaxial tensile testing device in an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the mounting plate in an embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram showing the connection relationship between the cross-shaped groove, slide rail, moving fixture, and solid propellant biaxial tensile specimen in an embodiment of the present invention.

[0023] Figure 4 This is a cross-sectional schematic diagram of the slide rail in an embodiment of the present invention;

[0024] Figure 5 This is an exploded view of the movable clamp and the movable pulley in an embodiment of the present invention;

[0025] Figure 6 This is a schematic diagram of the loading mechanism in an embodiment of the present invention;

[0026] Figure 7 This is a schematic diagram of the rope connection pulley combination in an embodiment of the present invention with a load ratio of 2:3;

[0027] Figure 8 This is a schematic diagram of the rope connection pulley combination in an embodiment of the present invention with a load ratio of 1:2;

[0028] Figure 9 This is a schematic diagram of the rope connection pulley combination when the load ratio is 1:2 and 2:3 in an embodiment of the present invention.

[0029] In the diagram: 1-Vertical bracket, 2-Mounting plate, 3-Slide rail, 4-Fixed pulley, 5-Moving pulley, 6-Moving clamp, 7-Loading mechanism, 8-Rope, 9-Solid propellant biaxial tensile specimen, 10-Moving pulley of loading mechanism, 11-Temperature and humidity control box, 12-T-shaped loading head, 13-Pattern, 14-Loading disc, 15-Cross-shaped groove, 16-Slide rail fixing hole, 17-Fixed pulley fixing hole, 18-Fixed pulley pad, 19-Plate fixing hole, 20-Plate fixing shaft, 21-Pin, 22-Moving block, 23-Propellant clamp, 24-Moving pulley pad, 25-I-shaped slide rail, 26-Counterhead hole, 27-Clamping screw, 28-Counterhead screw. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] The purpose of this invention is to provide a biaxial tensile testing device and method for solid propellants to solve the problems existing in the prior art. It can realize biaxial tensile testing of solid propellant creep load under different loading ratios. The device has a simple and compact structure and low economic cost.

[0032] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] Example 1

[0034] like Figures 1-6As shown, this embodiment provides a solid propellant biaxial tensile testing device, including a vertical support 1, a mounting plate 2, slide rails 3, fixed pulleys 4, movable pulleys 5, a movable clamp 6, a loading mechanism 7, and a rope 8. The mounting plate 2 is fixedly mounted on the vertical support 1. Four slide rails 3 are mounted on the mounting plate 2, and the four slide rails 3 are distributed at equal angles in a cross shape. A movable clamp 6 is slidably mounted on each slide rail 3. One end of the movable clamp 6 near the center of the cross of the four slide rails 3 is used to connect the solid propellant biaxial tensile specimen 9, and the other end is equipped with a... Several movable pulleys 5 are provided, and several fixed pulleys 4 are provided on the outer side of the end of each slide rail 3 away from the center of the cross. The fixed pulleys 4 are mounted on the mounting plate 2. The loading mechanism 7 has several loading mechanism movable pulleys 10. The rope 8 is used to connect the loading mechanism movable pulleys 10, fixed pulleys 4 and movable pulleys 5, and suspend the loading mechanism 7 below the mounting plate 2. The loading mechanism 7 is used to transmit the loading force through the rope 8, fixed pulleys 4 and movable pulleys 5, and then provide creep load to the solid propellant biaxial tensile specimen 9 through the moving clamp 6 to realize biaxial tensile loading.

[0035] This device can build different combinations of movable and fixed pulleys by changing the position of the rope 8 in the loading mechanism's movable pulley 10, fixed pulley 4, and movable pulley 5, thereby achieving biaxial tensile loading with different load ratios. Combined with the loading mechanism 7 to provide creep load, it can complete biaxial tensile performance tests of solid propellants under different loads. The structure is simple, compact, and economical.

[0036] The solid propellant biaxial tensile specimen 9 is a cross-shaped specimen, with its four ends mounted in four movable clamps 6. Two slide rails 3 are horizontally arranged, and the other two slide rails 3 are vertically arranged. The movable clamps 6 can move unidirectionally (horizontally or vertically) on the slide rails 3 to ensure the accuracy of the loading direction. Each slide rail 3 has three fixed pulleys 4 on its outer side away from the center of the cross. The fixed pulleys 4 on the upper and lower sides are symmetrically arranged about the horizontal slide rails 3, and the fixed pulleys 4 on the left and right sides are symmetrically arranged about the vertical slide rails 3, which can realize the testing of equal biaxial tensile and variable biaxial performance of solid propellants under different proportion creep loads. The loading mechanism 7 has three loading mechanism movable pulleys 10.

[0037] In this embodiment, a temperature and humidity environment control box 11 is also included. The mounting plate 2 and the loading mechanism 7 are both disposed inside the temperature and humidity environment control box 11. The temperature and humidity environment control box 11 is fixedly installed in the center of the vertical support 1. Its interior is a sealed space used to regulate environmental parameters such as temperature and humidity to simulate the biaxial tensile behavior of solid propellants under different storage environments.

[0038] In this embodiment, the loading mechanism 7 includes a T-shaped loading head 12, a tray 13, and multiple loading discs 14. A movable pulley 10 is mounted on the T-shaped loading head 12, the tray 13 is fixed to the lower end of the T-shaped loading head 12, and the loading discs 14 are placed on the tray 13. By changing the number of loading discs 14 placed on the tray 13, the tensile load applied by the loading mechanism 7 can be adjusted, thereby enabling the study of the creep characteristics of the biaxial tensile specimen 9 of the solid propellant.

[0039] In this embodiment, the mounting plate 2 is an octagonal flat plate, preferably a regular octagonal flat plate.

[0040] In this embodiment, the octagonal plate has a cross-shaped groove 15 in the middle, and slide rail fixing holes 16 are evenly distributed in the cross-shaped groove 15 for fixing the slide rail 3 by screws.

[0041] In this embodiment, the mounting plate 2 is provided with a fixed pulley fixing hole 17, the fixed pulley 4 is installed and fixed in the fixed pulley fixing hole 17, and a fixed pulley pad 18 is provided between the fixed pulley 4 and the mounting plate 2.

[0042] In this embodiment, each of the outer surfaces of the octagonal plate corresponding to the end of each slide rail 3 furthest from the center of the cross is provided with a plate fixing hole 19. The plate fixing hole 19 is used to connect the plate fixing shaft 20, which is fixed to the vertical bracket 1 by a pin 21. One end of the plate fixing shaft 20 passes through a small hole opened at the top of the temperature and humidity control box 11 and is fixedly connected to the octagonal plate, while the other end is fixed to the vertical bracket 1 by a pin 21, thereby achieving axial positioning and support of the mounting plate 2.

[0043] In this embodiment, the movable clamp 6 includes a movable block 22 and a propellant clamp 23. The movable block 22 is slidably disposed on the slide rail 3. The propellant clamp 23 is fixedly installed on the movable block 22 and close to the cross center of the slide rail 3. The solid propellant biaxial tensile specimen 9 is fixedly installed in the propellant clamp 23. The specimen is stabilized by the propellant clamp 23 to achieve biaxial tensile loading. Several movable pulleys 5 are installed at the end of the movable block 22 away from the cross center. Movable pulley pads 24 are provided between the movable pulleys 5 and the movable block 22. The movable pulley pads 24 provide structural support for the movable pulleys 5 and avoid interference between the mounting plate 2 and the rope 8.

[0044] In this embodiment, the slide rail 3 has an I-shaped cross-section, and the moving block 22 has an I-shaped slide track 25 that mates with the I-shaped slide rail 3, ensuring that the moving block 22 can move stably along the slide rail 3. The slide rail 3 is provided with countersunk holes 26, in which countersunk screws 28 are installed. The countersunk screws 28 are threaded into the slide rail fixing holes 16, making installation convenient and quick. The propellant clamp 23 is fixed to the moving block 22 by clamp screws 27, facilitating disassembly and assembly.

[0045] like Figure 7 The diagram shows the rope 8 connection to the pulley assembly of this device at a load ratio of 2:3, where the load ratio refers to the ratio of the load on the sample to the weight of the loading mechanism; as shown... Figure 8 The diagram shown is a schematic of the rope 8 connecting to the pulley assembly when the load ratio is 1:2. Figure 9 The diagram shows the rope 8 connection pulley combination for mixed load ratios of 1:2 and 2:3. The left and right sides of the sample have a load ratio of 1:2, while the top and bottom sides have a load ratio of 2:3. By adjusting the path relationship of rope 8 between the fixed pulley 4, the movable pulley 5, and the movable pulley 10 of the loading mechanism, various load ratio pulley combinations can be constructed, thereby meeting the testing requirements for isoaxial tensile and variable biaxial tensile behaviors under different load ratios.

[0046] Example 2

[0047] This embodiment provides a method for biaxial tensile testing of solid propellants, based on the biaxial tensile testing device for solid propellants described in Embodiment 1, including the following steps:

[0048] The solid propellant biaxial tensile specimen 9 is connected to four movable clamps 6. The loading force of the loading mechanism 7 is set and the loading ratio is determined. The moving pulley 10, fixed pulley 4 and moving pulley 5 of the loading mechanism are connected by rope 8. The loading mechanism 7 is suspended below the mounting plate 2 and a biaxial tensile test is carried out.

[0049] The specific process is as follows:

[0050] (1) Preparation of solid propellant biaxial tensile specimen 9;

[0051] (2) Fix the propellant clamp 23 to the moving block 22 by clamp screw 27, and install the movable pulley 5 and the movable pulley pad 24 on the moving block 22;

[0052] (3) Embed the assembled movable clamp 6 into the slide rail 3, and fix the slide rail 3 to the octagonal plate with countersunk screws 28;

[0053] (4) Install the fixed pulley 4 and the fixed pulley pad 18 around the octagonal plate respectively;

[0054] (5) Open the temperature and humidity control box 11, install the octagonal plate, and fix it to the vertical bracket 1 with pins 21;

[0055] (6) Install the moving pulley 10 of the loading mechanism onto the T-shaped loading head 12, and select an appropriate number of loading disks 14;

[0056] (7) Determine the loading ratio and connect the movable pulley 10, fixed pulley 4 and movable pulley 5 of the loading mechanism with rope 8;

[0057] (8) Place the solid propellant biaxial tensile specimen 9 into the propellant fixture 23;

[0058] (9) Close the door of the temperature and humidity control box 11, set the temperature and humidity, and start the test.

[0059] This invention enables the testing of isoaxial tensile and variable biaxial properties of solid propellants under high temperature and high humidity environments and different proportions of creep loads by using different combinations of moving and fixed pulleys and the number of loading disks.

[0060] The symmetrical design of the movable pulley, fixed pulley, and moving clamp in this invention enables more accurate simulation of creep fracture behavior of propellant under biaxial tensile load, ensuring a high degree of assurance of test data.

[0061] This invention proposes a novel biaxial tensile testing device and method for solid propellants. By constructing a pulley-based biaxial tensile testing device, stable and adjustable proportional biaxial tensile loading and deformation response monitoring of propellant samples are achieved under controlled environmental conditions. The combined design of the slide rail and moving clamp structure ensures the centering and loading direction accuracy of the sample during the tensile process, meeting the mechanical property testing requirements under complex service conditions. This invention provides a precise and efficient experimental means for propellant material reliability assessment and multiaxial performance research.

[0062] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A biaxial tensile testing device for solid propellants, characterized in that: The system includes a vertical support, a mounting plate, slide rails, fixed pulleys, movable pulleys, a movable clamp, a loading mechanism, and a rope. The mounting plate is fixedly mounted on the vertical support. Four slide rails are mounted on the mounting plate, arranged in a cross shape at equal angles. A movable clamp slides on each slide rail. One end of the movable clamp, near the center of the cross, is used to connect a solid propellant biaxial tensile specimen, and the other end is equipped with several movable pulleys. Several fixed pulleys are located on the outer side of the end of each slide rail away from the center of the cross, and the fixed pulleys are mounted on the mounting plate. The loading mechanism has several movable pulleys. The rope connects the movable pulleys, fixed pulleys, and movable pulleys, suspending the loading mechanism below the mounting plate. The rope is a single rope, which connects the movable pulleys, fixed pulleys, and movable pulleys to create different movable-fixed pulley combinations, achieving biaxial tensile loading with different load ratios.

2. The solid propellant biaxial tensile testing device according to claim 1, characterized in that: It also includes a temperature and humidity environment control box, and the mounting plate and the loading mechanism are both located inside the temperature and humidity environment control box.

3. The solid propellant biaxial tensile testing device according to claim 1, characterized in that: The loading mechanism includes a T-shaped loading head, a tray, and multiple loading discs. The loading mechanism's movable pulley is mounted on the T-shaped loading head, the tray is fixed to the lower end of the T-shaped loading head, and the loading discs are placed on the tray.

4. The solid propellant biaxial tensile testing device according to claim 1, characterized in that: The mounting plate is an octagonal flat plate.

5. The solid propellant biaxial tensile testing device according to claim 4, characterized in that: The octagonal plate has a cross-shaped groove in the middle, and slide rail fixing holes are evenly distributed in the cross-shaped groove for fixing the slide rail by screws.

6. The solid propellant biaxial tensile testing device according to claim 1, characterized in that: The mounting plate is provided with a fixed pulley fixing hole, the fixed pulley is installed and fixed in the fixed pulley fixing hole, and a fixed pulley pad is provided between the fixed pulley and the mounting plate.

7. The solid propellant biaxial tensile testing device according to claim 4, characterized in that: Each of the octagonal flat plates has a plate fixing hole on its outer side corresponding to the end of each slide rail away from the center of the cross. The plate fixing hole is used to connect a plate fixing shaft, which is fixed to the vertical bracket by a pin.

8. The solid propellant biaxial tensile testing device according to claim 1, characterized in that: The movable clamp includes a movable block and a propellant clamp. The movable block is slidably disposed on the slide rail. The propellant clamp is fixedly installed on the movable block and close to the cross center of the slide rail. A plurality of movable pulleys are installed at the end of the movable block away from the cross center. Movable pulley pads are provided between the movable pulleys and the movable block.

9. The solid propellant biaxial tensile testing device according to claim 8, characterized in that: The slide rail has an I-shaped cross-section, and the moving block has an I-shaped slide track that mates with the I-shaped slide rail; the propellant clamp is fixed to the moving block by clamp screws.

10. A method for biaxial tensile testing of solid propellants, characterized in that, The solid propellant biaxial tensile testing apparatus based on any one of claims 1 to 9 includes the following steps: The solid propellant biaxial tensile specimen is connected to the four movable clamps. The loading force of the loading mechanism is set, the loading ratio is determined, and the movable pulley, fixed pulley, and loading mechanism are connected by the rope. The loading mechanism is suspended below the mounting plate for biaxial tensile testing.

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