Efficient in-situ testing device for mechanical-thermal coupling of solid propellant in scanning electron microscope

Abstract

The invention relates to an efficient in-situ testing device for mechanical and thermal coupling of a solid propellant in a scanning electron microscope, belongs to the technical field of precise scientific instruments and material micro-mechanical property testing, and solves the problem that in-situ testing equipment of an existing scanning electron microscope cannot construct a stable temperature field for a solid propellant sample which is subjected to large deformation. The device comprises a mechanical loading assembly used for applying a mechanical load to a solid propellant sample; the load loading and measuring assembly is arranged on the loading cross beam and is used for measuring the mechanical load of the solid propellant sample; the liquid circulating heat-conducting assembly is used for continuously transferring heat of a circulating heat-conducting medium to the solid propellant sample along with the movement of the two loading cross beams and applying a stable thermal load; the vacuum circulating pipeline assembly is used for forming a closed-loop heat transfer channel; and the pipeline telescopic assembly is used for adjusting the imaging position of the in-situ testing device main body in the scanning electron microscope cabin. According to the invention, force thermal coupling loading and accurate load measurement of the solid propellant are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of precision scientific instruments and the testing technology of the micro-mechanical properties of materials, and particularly relates to a high-efficiency in-situ testing device for the force-thermal coupling of solid propellants inside a scanning electron microscope. Background Art

[0002] Solid propellants are not only the energy source of solid rocket motors but also an important engineering component of solid rocket motors. Since solid propellants are viscoelastic materials, their mechanical properties are not only related to the loading rate but also to the service environment temperature. During the action of complex mechanical loads and temperature loads in a wide temperature range, micro-defect propagation and mechanical property degradation are extremely likely to occur in solid propellants.

[0003] Scanning electron microscopes (referred to as SEMs for short) have the advantages of large depth of field in imaging, wide field of view, good three-dimensional imaging effect, and steplessly adjustable magnification, and are widely used in the characterization of the microstructures of materials. Therefore, many scientific researchers use SEMs to obtain the fracture surfaces of solid propellants under the action of loads such as different temperatures and strain rates. This ex-post analysis method can only infer part of the reasons for the fracture of the propellant through the fracture morphology, and it is difficult to reveal the failure mechanism during loading. By combining the method of scanning electron microscopy and in-situ tensile test technology, the micro-failure modes of the propellant during the loading process can be obtained. Currently, in-situ testing equipment for carrying out mechanical property tests on solid propellant specimens under a scanning electron microscope can often only apply a single mechanical load to the solid propellant specimens and cannot construct a stable temperature field for solid propellant specimens with large deformations. If a service environment with the coupling of mechanical loads and temperature loads can be constructed for solid propellant specimens inside a scanning electron microscope, it has an important role in revealing the structure-property relationship between the macroscopic mechanical properties and micro-damage evolution of solid propellants. Therefore, it is of great significance to study the work of a high-efficiency in-situ testing device for the force-thermal coupling of solid propellants inside a scanning electron microscope. Summary of the Invention

[0004] The purpose of the present invention is to provide a high-efficiency in-situ testing device for the force-thermal coupling of solid propellants inside a scanning electron microscope to solve the problems existing in the above-mentioned prior art. The device controls the mechanical loading on the solid propellant specimen through a mechanical loading component. During the mechanical loading process, the heat in the circulating heat-conducting medium is transferred to the sliding-attached heat-conducting component through a liquid circulating heat-conducting component. The sliding-attached heat-conducting component moves with the loading crossbeam and synchronously realizes contact heat conduction, and finally transfers the heat to the solid propellant specimen through the load loading and measuring component, realizing the force-thermal coupling loading and the material mechanical property testing of the solid propellant specimen, and providing an important technical means for revealing the failure mechanism of the propellant in the force-thermal coupling effect.

[0005] To solve the above technical problems, the present invention adopts the following technical solutions:

[0006] An efficient in-situ testing device for the thermo-mechanical coupling of solid propellants inside a scanning electron microscope, comprising a pipeline telescopic assembly connected to the scanning electron microscope cabin body and an in-situ testing device main body located inside the scanning electron microscope cabin body. The in-situ testing device main body includes a mechanical loading assembly, a vacuum circulation pipeline assembly, a load loading and measuring assembly, and a liquid circulation heat conduction assembly;

[0007] The mechanical loading assembly is used to apply mechanical loads to the solid propellant specimens;

[0008] The load loading and measuring assembly is arranged on two loading crossbeams of the mechanical loading assembly, and is used to clamp the solid propellant specimens and measure the mechanical loads of the solid propellant specimens by using force sensors;

[0009] The liquid circulation heat conduction assembly is used to continuously transfer the heat of the circulating heat conduction medium to the solid propellant specimens following the movement of the two loading crossbeams, and apply stable thermal loads to the solid propellant specimens;

[0010] The vacuum circulation pipeline assembly includes a vacuum bellows located inside the scanning electron microscope cabin body. The vacuum bellows are respectively communicated with the liquid circulation heat conduction assembly and the outer circulation pipeline in the pipeline telescopic assembly to form a closed-loop heat transfer channel;

[0011] The pipeline telescopic assembly is fixed on the cabin wall of the scanning electron microscope, and is used to adjust the imaging position of the in-situ testing device main body inside the scanning electron microscope cabin body by driving the displacement of the vacuum bellows on the premise of maintaining the vacuum degree of the scanning electron microscope.

[0012] An efficient in-situ testing device for the thermo-mechanical coupling of solid propellants inside a scanning electron microscope proposed by the present invention has the following beneficial effects: The efficient in-situ testing device of the present invention can synchronously construct tensile loads with different strain rates and temperature loads in a wide temperature range for solid propellants in a scanning electron microscope, can continuously and stably apply temperature loads to solid propellants during tensile loading, and cooperate with the scanning electron microscope to carry out multi-scale mechanical property tests on solid propellants under the action of thermo-mechanical coupling, providing a dedicated and efficient testing device for the in-situ testing of the mechanical properties of solid propellants under the influence of service temperature, and providing an important testing and characterization device for deeply revealing the deformation, damage and failure mechanisms of solid propellants under the action of thermo-mechanical coupling. Description of the Drawings

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

[0014] Figure 1 Schematic diagram of the overall structure of the high-efficiency in-situ test device for the thermo-mechanical coupling of solid propellants installed inside a scanning electron microscope;

[0015] Figure 2 Schematic diagram of the overall structure of the high-efficiency in-situ test device;

[0016] Figure 3 Schematic diagram of the overall structure of the liquid circulation heat conduction component;

[0017] Figure 4 Schematic diagram of the installation and connection structure of the liquid circulation heat conduction component;

[0018] Figure 5 For Figure 4 Local enlarged schematic diagram of area 4A in

[0019] Figure 6 Schematic diagram of the structure of the load measurement component;

[0020] Figure 7 Schematic diagram of the overall structure of the pipeline expansion and contraction component.

[0021] Explanation of reference numerals: 1. Pipeline expansion and contraction component; 11. Cam-type telescopic pipeline component; 111. Locking nut; 112. Sliding traction seat; 113. Sliding guide column; 114. Rotating cam; 115. Guide cylinder; 116. Disc-type bellows; 117. Bellows flange; 12. Outer circulation pipeline; 121. Ferrule-type pipe joint; 122. Pipe passing through flange; 123. Circulation pipeline flange;

[0022] 2. Scanning electron microscope cabin; 21. Pole shoe; 22. Oblique-angled rectangular flange;

[0023] 3. In-situ test device main body;

[0024] 31. Mechanical loading component; 311. Bidirectional trapezoidal lead screw; 312. Loading cross beam; 313. Displacement measurement component; 314. Driving component;

[0025] 32. Vacuum circulation pipeline component; 321. Pipeline fixing seat; 322. Vacuum bellows; 323. Vacuum pipeline joint; 324. Heat insulation connection seat;

[0026] 33. Load loading and measuring assembly; 331. Load measuring assembly; 3311. Force sensor fixing plate; 3312. Force sensor; 3313. Fixture positioning plate; 3314. Round nut; 3315. Hexagon lock nut; 332. Fixture assembly; 3321. Frost-proof fixture cover; 3322. Heat-conducting upper cover; 3323. Heat-conducting fillet; 3324. Heat-insulating fixture base; 3325. High heat-conducting connection base; 3326. Solid support bracket; 333. Solid propellant sample.

[0027] 34. Liquid circulation heat-conducting assembly; 341. Heat input assembly; 3411. Liquid circulation heat-conducting plate; 3412. Heat-conducting plate fixing bracket; 3413. Heat-conducting plate fixing chute; 3414. Protective housing; 342. Heat-conducting support assembly; 3421. Heat-insulating installation body; 3422. Heat-insulating chute; 3423. Friction heat-conducting plate; 343. Sliding attachment heat-conducting assembly; 3431. Sliding traction bracket; 3432. First sliding heat-conducting block bracket; 3433. First pressing slider; 3434. First optical rod bearing; 3435. Sliding heat-conducting cover; 3436. Sliding heat-conducting seat; 3437. Vacuum heat-conducting grease; 344. Middle fixed heat-conducting assembly; 3441. Middle sliding heat-conducting seat; 3442. Middle heat-conducting positioning block; 3443. Middle adjustable heat-conducting plate. Specific implementation mode

[0028] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0029] As Figures 1 to 7 shown, the present invention provides an efficient in-situ test device for the force-thermal coupling of solid propellants in a scanning electron microscope, including a pipeline telescopic assembly 1 and an in-situ test device main body 3. Among them, the pipeline telescopic assembly 1 is fixedly connected to the cabin wall of the scanning electron microscope cabin 2 through an inclined rectangular flange 22, and the in-situ test device main body 3 is located inside the scanning electron microscope cabin 2.

[0030] The in-situ testing device main body 3 includes a mechanical loading component 31, a vacuum circulation pipeline component 32, a load loading and measuring component 33, and a liquid circulation heat conduction component 34. Among them, the mechanical loading component 31 is used to apply a stable mechanical load to the solid propellant specimen 333; the load loading and measuring component 33 is arranged on two loading crossbeams 312 in the mechanical loading component 31, and is used to clamp the solid propellant specimen 333 and measure the mechanical load of the solid propellant specimen 333 by using a force sensor 3312; the liquid circulation heat conduction component 34 is used to continuously transfer the heat of the circulating heat conduction medium to the solid propellant specimen following the movement of the two loading crossbeams, and apply a stable thermal load to the solid propellant specimen; the vacuum circulation pipeline component 32 includes a vacuum bellows 322 located in the scanning electron microscope cabin 2, and the vacuum bellows 322 is respectively communicated with the liquid circulation heat conduction component 34 and the outer circulation pipeline 12 in the pipeline telescopic component 1 to form a closed-loop heat transfer channel; the pipeline telescopic component 1 is fixed on the cabin wall of the scanning electron microscope, and is used to adjust the imaging position of the in-situ testing device main body 3 in the scanning electron microscope cabin 2 by driving the displacement of the vacuum bellows 322 on the premise of maintaining the vacuum degree of the scanning electron microscope.

[0031] The mechanical loading component 31 includes two loading crossbeams 312 and a bidirectional trapezoidal lead screw 311 that is threadedly engaged with the two loading crossbeams 312. The bidirectional trapezoidal lead screw 311 drives the two loading crossbeams 312 to move towards each other, thereby driving the load loading and measuring component 33 thereon to move and applying a tensile load to the solid propellant specimen 333 clamped in the load loading and measuring component 33. Among them, the driving of the bidirectional trapezoidal lead screw 311 is completed by a driving component 314. The driving component 314 uses a servo motor and a worm and worm gear mechanism to drive the bidirectional trapezoidal lead screw 311, and at the same time, a displacement measuring component 313 measures the moving distance between the two loading crossbeams 312 in real time. For example, the displacement measuring component 313 can use grating scales and grating reading heads respectively arranged in the two loading crossbeams 312 to measure the moving distance, so as to more accurately control the mechanical load applied to the solid propellant specimen 333.

[0032] The load loading and measuring component 33 includes a load measuring component 331 and a pair of fixture components 332 installed in the loading crossbeams 312. The pair of fixture components 332 are respectively fixedly connected to the two loading crossbeams 312.

[0033] Each fixture assembly 332 includes a thermally conductive upper cover 3322, a heat-insulating fixture base 3324, a highly thermally conductive connection base 3325, and a mounting base. One end of the highly thermally conductive connection base 3325 with a high thermal conductivity is mounted in the heat-insulating fixture base 3324 with a low thermal conductivity through a small boss. The highly thermally conductive connection base 3325 and the thermally conductive upper cover 3322 respectively wrap the lower surface and the upper surface of the clamping end of the solid propellant specimen 333. The fixture assembly 332 can transfer heat to the solid propellant specimen 333. A mounting base is provided on one side of the heat-insulating fixture base 3324. The fixture assembly 332 is connected to the corresponding loading crossbeam 312 through the mounting base.

[0034] Further, each fixture assembly 332 further includes a frost-proof fixture cover 3321. The frost-proof fixture cover 3321 is made of a polyimide material with a low thermal conductivity and is mounted on the upper surface of the thermally conductive upper cover 3322, which can prevent frosting on the upper surface of the thermally conductive upper cover 3322 during the low-temperature loading process and affect the imaging effect of the scanning electron microscope.

[0035] Each fixture assembly 332 further includes a pair of thermally conductive fillets 3323. Each thermally conductive fillet 3323 has the same curvature as the fillet of the solid propellant specimen 333 and is mounted in the highly thermally conductive connection base 3325 for applying a load to the fillet of the solid propellant specimen 333 and transferring heat.

[0036] Each fixture assembly 332 further includes a solid support bracket 3326. The solid support bracket 3326 is mounted on the upper surface of the heat-insulating fixture base 3324 and has good stiffness, which is used to increase the stiffness of the heat-insulating fixture base 3324 and prevent the heat-insulating fixture base 3324 from deforming during the mechanical loading process.

[0037] The load measurement assembly 331 includes a force sensor fixing plate 3311, a force sensor 3312, a fixture positioning plate 3313, a round nut 3314, and a hexagon lock nut 3315. The external thread of the small pitch end of the hexagon lock nut 3315 is connected to the mounting seat of one of the fixture assemblies 332, and the internal thread of the large pitch end of the hexagon lock nut 3315 is connected to one end of the force sensor 3312. The other end of the force sensor 3312 passes through the through hole on the force sensor fixing plate 3311 and is fixedly connected to the round nut 3314, realizing the axial fixation of the force sensor 3312 and the force sensor fixing plate 3311. The force sensor 3312 is used to measure the tensile load of the solid propellant sample 333 and has a certain temperature compensation function. Optionally, the force sensor 3312 can adopt the sensor of the WMC series of Interface Company, with a range of 45N. The fixture positioning plate 3313 can determine the rotation angle of the fixture. The two ends of the fixture positioning plate 3313 are respectively connected to the force sensor fixing plate 3311 and the mounting seat in the fixture assembly 332. The mounting seat is cylindrical, and a plane in contact with the fixture positioning plate 3313 is provided on the side of the cylinder. This plane is used to position the rotation angle between the fixture positioning plate 3313 and the fixture as required. As long as the fixture positioning plate 3313 is installed well, the relative angle between the force sensor 3312 and the fixture assembly 332 is determined, which can prevent the fixture from rotating relative to the force sensor 3312 during the mechanical loading test. The load measurement assembly 331 and the fixture assembly 332 can accurately obtain the millinewton-level mechanical load of the solid propellant sample 333.

[0038] The liquid circulation heat conduction assembly 34 includes a heat input assembly 341, a heat conduction support assembly 342, a sliding attachment heat conduction assembly 343, and a middle fixed heat conduction assembly 344.

[0039] The heat input assembly 341 includes a liquid circulation heat conduction plate 3411, a heat conduction plate fixing bracket 3412, and a group of heat conduction plate fixing chutes 3413 installed on the heat insulation mounting body 3421. Among them, a flow channel communicating with the vacuum bellows 322 is provided inside the liquid circulation heat conduction plate 3411. The heat conduction plate fixing bracket 3412 provides support for the liquid circulation heat conduction plate 3411. The heat conduction plate fixing bracket 3412 with screws installed can slide up and down along the heat conduction plate fixing chute 3413, and the heat conduction plate fixing bracket 3412 is fixed to the heat conduction plate fixing chute 3413 by screws, so as to press the liquid circulation heat conduction plate 3411 against the friction heat conduction plate 3423, enabling the liquid circulation heat conduction plate 3411 to conduct the heat in the circulating medium to the friction heat conduction plate 3423.

[0040] Furthermore, the heat input component 341 further includes a protective housing 3414 which is installed on the upper surface of the heat conduction plate fixing chute 3413 and is used to prevent foreign objects, dust, etc. from invading the liquid circulation heat conduction component 34.

[0041] The heat conduction support component 342 includes a heat insulation installation main body 3421, a heat insulation chute 3422 and a friction heat conduction plate 3423. Among them, the inner groove of the heat insulation chute 3422 is inlaid and connected with the friction heat conduction plate 3423, and the outer frame of the heat insulation chute 3422 is threadedly connected to the internal positioning surface of the heat insulation installation main body 3421.

[0042] The liquid circulation heat conduction component 34 includes two groups of synchronously sliding sliding attachment type heat conduction components 343 and a middle fixed heat conduction component 344. Both the sliding attachment type heat conduction component 343 and the middle fixed heat conduction component 344 include a pressing type slider and a sliding heat conduction block bracket installed with two groups of optical rod bearings. The optical rod bearings are connected to the lower surface of the corresponding pressing type slider by threads and contact the heat insulation chute 3422. In the sliding attachment type heat conduction component 343, both sides of the first sliding heat conduction block bracket 3432 are respectively connected to the first pressing type slider 3433 and the sliding heat conduction seat 3436 by threads, and can press the sliding heat conduction seat 3436 on the surface of the friction heat conduction plate 3423. The friction heat conduction plate 3423 conducts heat to the sliding heat conduction seat 3436. The sliding traction bracket 3431 is fixedly connected to the first sliding heat conduction block bracket 3432 and the loading cross beam 312 respectively. The loading cross beam 312 can traction the sliding attachment type heat conduction component 343 to slide linearly along the surface of the friction heat conduction plate 3423. A space is formed between the sliding heat conduction seat 3436 and the sliding heat conduction cover 3435 to wrap one end of the high heat conduction connection seat 3325 that does not clamp the solid propellant sample 333. The first optical rod bearing 3434 is connected to the lower surface of the first pressing type slider 3433 by threads and contacts the heat insulation chute 3422. In the middle fixed heat conduction component 344, both sides of the second sliding heat conduction block bracket are respectively connected to the second pressing type slider and the middle sliding heat conduction seat 3441 by threads, and can press the middle sliding heat conduction seat 3441 on the surface of the friction heat conduction plate 3423. The friction heat conduction plate 3423 conducts heat to the middle sliding heat conduction seat 3441. And the middle sliding heat conduction seat 3441 is connected to the middle heat conduction positioning block 3442. The upper surface of the middle heat conduction positioning block 3442 is connected to the middle sliding heat conduction seat 3441 in the middle fixed heat conduction component 344, and its lower surface is installed in the groove of the heat insulation installation main body 3421. The middle heat conduction positioning block 3442 is used to determine the relative position between the middle fixed heat conduction component 344 and the heat insulation installation main body 3421. The middle adjustable heat conduction plate 3443 is installed in the groove on the middle sliding heat conduction seat 3441, and the upper surface of the middle adjustable heat conduction plate 3443 contacts the solid propellant sample 333, and can transfer heat from the middle sliding heat conduction seat 3441 to the solid propellant sample 333. The second optical rod bearing is connected to the lower surface of the second pressing type slider by threads and contacts the heat insulation chute 3422.

[0043] Furthermore, there is a gap of about 0.5 mm between the highly thermally conductive connection base 3325, the sliding thermally conductive cover 3435, and the sliding thermally conductive base 3436. This gap can compensate for the minute deformation generated when the force sensor 3312 is stressed. At the same time, a vacuum thermal grease 3437 is filled in the gap, thereby transferring heat from the sliding attachment type thermally conductive component 343 to the highly thermally conductive connection base 3325 more efficiently. By adopting a heat conduction method in series with sliding friction heat conduction and flexible filling heat conduction with thermal grease, heat is transferred to the fixture component with a high thermal conductivity, effectively improving the thermal load loading capacity of the device while ensuring the accuracy of mechanical load measurement.

[0044] The vacuum circulation pipeline assembly 32 includes a pipeline fixing base 321, a vacuum bellows 322, a vacuum pipeline joint 323, and a heat insulation connection base 324. Among them, one end of the vacuum bellows 322 is connected to the flow channel inside the liquid circulation heat conducting plate 3411 through the vacuum pipeline joint 323, and the vacuum bellows 322 is fixedly connected to the heat insulation connection base 324 through the pipeline fixing base 321. The other end of the vacuum bellows 322 is connected to the outer circulation pipeline 12 installed in the pipeline telescopic assembly 1. The liquid circulation heat conducting component 34 is connected to the loading crossbeam 312 of the mechanical loading component 31 through a thread on one hand, and on the other hand, is flexibly connected to the highly thermally conductive connection base 3325 of the fixture component 332 in the load loading and measuring component 33 through the compressible and flowable vacuum thermal grease 3437. The circulating heat conducting medium flows through the outer circulation pipeline 12, the vacuum circulation pipeline assembly 32, and the liquid circulation heat conducting component 34 in sequence, and completes heat exchange through convective heat transfer in the heat input component 341, and inputs the heat into the in-situ test device main body 3. The heat is transferred to the solid propellant specimen 333 through the contact heat conduction between the heat conducting support component 342, the sliding attachment type thermally conductive component 343, and the middle fixed thermally conductive component 344. The in-situ test device can still apply a stable thermal load to the solid propellant specimen 333 through contact heat conduction during the tensile process of the solid propellant specimen 333 by the mechanical loading component 31.

[0045] The pipeline telescopic assembly 1 is used to widely adjust the imaging position of the in-situ test device main body 3 connected to the terminal of the vacuum bellows 322 in the chamber of the scanning electron microscope. It specifically includes a cam type telescopic pipeline assembly 11 and an outer circulation pipeline 12.

[0046] The cam-type telescopic pipe assembly 11 includes a lock nut 111, a sliding traction seat 112, a sliding guide post 113, a rotating cam 114, and a guide cylinder 115. The liquid circulation heat conducting plate 3411 and the through-flange pipe 122 in the heat input assembly 341 are both connected to the vacuum bellows 322 through the vacuum pipe joint 323. The sliding guide post 113 is simultaneously installed in the spiral groove of the rotating cam 114 and the linear groove of the guide cylinder 115. The sliding guide post 113 is threadedly connected to the sliding traction seat 112 located inside the rotating cam 114. The sliding traction seat 112 is circumferentially connected to the sliding guide post 113 through threads, and the sliding traction seat 112 is axially connected to the circulation pipe flange 123. Moreover, the sliding guide post 113 is simultaneously in contact with the spiral groove of the rotating cam 114 and the linear groove of the guide cylinder 115. The rotating cam 114 can rotate to enable the circulation pipe flange 123 to linearly slide along the inner wall of the guide cylinder 115. The linearly sliding circulation pipe flange 123 can drag the vacuum bellows 322 and the in-situ test device main body 3 closer to or farther away from the electron microscope bulkhead.

[0047] The lock nut 111 is threadedly connected to the guide cylinder 115. Rotating the lock nut 111 can adjust the sliding friction force between the rotating cam 114 and the guide cylinder 115, realize the locking of the circumferential position of the rotating cam 114, and further lock the relative position between the rotating cam 114 and the guide cylinder 115.

[0048] When rotating the rotating cam 114, while the sliding guide post 113 slides along the tangent direction of the spiral groove of the rotating cam 114, it still needs to maintain the tangential sliding along the linear groove of the guide cylinder 115. The sliding guide post 113 linearly moves along the slot hole of the guide cylinder 115, and drives the connected sliding traction seat 112, circulation pipe flange 123, and vacuum bellows 322 to linearly move along the axis of the guide cylinder 115.

[0049] Furthermore, the pipe telescopic assembly 1 further includes a disc-type bellows 116 and a bellows flange 117. The circulation pipe flange 123 is connected to one end of the disc-type bellows 116 to seal the disc-type bellows 116. The other end of the disc-type bellows 116 is connected to the bellows flange 117 by welding, and the bellows flange 117 is fixedly connected to the bevel rectangular flange 22. The disc-type bellows 116 is connected to the scanning electron microscope cabin body 2 through the bellows flange 117 to form a vacuum environment with the scanning electron microscope cabin body 2. During the movement, the disc-type bellows 116 is stretched / compressed, but the vacuum degree inside the scanning electron microscope cavity can be always maintained. The function of the disc-type bellows 116 is to enable the vacuum bellows 322 to have a certain moving space while ensuring the vacuum inside the scanning electron microscope cabin body 2. The vacuum bellows 322 does not need to be directly connected to the bulkhead of the scanning electron microscope cabin body 2, so as to realize the large-range adjustment of the imaging position of the in-situ test device main body 3 inside the scanning electron microscope cabin body 2.

[0050] The object of the present invention is to provide an efficient in-situ test device for the thermo-mechanical coupling of solid propellants in a scanning electron microscope, so as to solve the problem in the prior art that the in-situ test equipment of the scanning electron microscope can only apply a single mechanical load to the solid propellant specimen and cannot construct a stable temperature field for the solid propellant specimen undergoing large deformation. The efficient in-situ test device includes a pipeline telescopic assembly and a main body of the in-situ test device. The main body of the in-situ test device includes a mechanical loading assembly, a vacuum circulation pipeline assembly, a load loading and measuring assembly, and a liquid circulation heat conduction assembly. Among them, by rotating the rotating cam in the pipeline telescopic assembly, the imaging position of the main body of the in-situ test device in the scanning electron microscope can be adjusted within a large range. The load loading and measuring assembly is installed on the end loading crossbeam of the mechanical loading assembly and is used for tensile loading of the solid propellant specimen and accurately obtaining mechanical loads at the millinewton level. The liquid circulation heat conduction assembly adopts a heat conduction method in series with sliding friction heat conduction and flexible filling heat conduction with heat-conducting grease to transfer heat to the fixture assembly with high thermal conductivity, effectively improving the thermal load loading capacity of the device while ensuring the accuracy of mechanical load measurement. The efficient in-situ test device has excellent thermo-mechanical coupling loading and accurate load measurement capabilities for solid propellants with low modulus and low thermal conductivity.

[0051] The efficient in-situ test device of the present invention can simultaneously construct tensile loads with different strain rates and temperature loads in a wide temperature range for solid propellants in a scanning electron microscope, can continuously and stably apply temperature loads to solid propellants during tensile loading, and cooperate with the scanning electron microscope to carry out multi-scale mechanical property tests on solid propellants under the action of thermo-mechanical coupling, providing a dedicated and efficient test device for the in-situ test of the mechanical properties of solid propellants under the influence of service temperature, and providing an important test characterization device for deeply revealing the deformation, damage and failure mechanisms of solid propellants under the action of thermo-mechanical coupling.

[0052] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

[0053] The above-described embodiments only represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent shall be subject to the appended claims.

Claims

1. An efficient in-situ test device for thermo-mechanical coupling of solid propellants in a scanning electron microscope, characterized in that, It includes a pipeline telescopic assembly (1) connected to the scanning electron microscope cabin body (2) and an in-situ testing device main body (3) located inside the scanning electron microscope cabin body (2). The in-situ testing device main body (3) includes a mechanical loading assembly (31), a vacuum circulation pipeline assembly (32), a load loading and measuring assembly (33), and a liquid circulation heat conduction assembly (34). The mechanical loading assembly (31) is used to apply mechanical loads to the solid propellant specimen (333). The load loading and measuring assembly (33) is arranged on two loading crossbeams (312) of the mechanical loading assembly (31) and is used to clamp the solid propellant specimen (333) and measure the mechanical load of the solid propellant specimen (333) by using a force sensor (3312). The liquid circulation heat conduction assembly (34) is used to continuously transfer the heat of the circulating heat conduction medium to the solid propellant specimen (333) following the movement of the two loading crossbeams (312), and apply a stable thermal load to the solid propellant specimen (333). The vacuum circulation pipeline assembly (32) includes a vacuum bellows (322) located inside the scanning electron microscope cabin body (2). The vacuum bellows (322) is respectively communicated with the liquid circulation heat conduction assembly (34) and the external circulation pipeline (12) in the pipeline telescopic assembly (1) to form a closed-loop heat transfer channel. The pipeline telescopic assembly (1) is fixed on the cabin wall of the scanning electron microscope and is used to adjust the imaging position of the in-situ testing device main body (3) inside the scanning electron microscope cabin body (2) by driving the displacement of the vacuum bellows (322) on the premise of maintaining the vacuum degree of the scanning electron microscope.

2. The high-efficiency in-situ testing device for solid propellant thermo-mechanical coupling in a scanning electron microscope according to claim 1, wherein, The mechanical loading assembly (31) includes two loading crossbeams (312) and a bidirectional trapezoidal lead screw (311) threadedly engaged with the two loading crossbeams (312). The bidirectional trapezoidal lead screw (311) drives the two loading crossbeams (312) to move towards each other.

3. The high-efficiency in-situ testing device for solid propellant thermo-mechanical coupling in a scanning electron microscope according to claim 1 or 2, characterized in that, The load loading and measuring assembly (33) includes a load measuring assembly (331) and a pair of fixture assemblies (332). The pair of fixture assemblies (332) are respectively fixedly connected to the two loading crossbeams (312). Each fixture assembly (332) includes a heat-conducting upper cover (3322), a heat-insulating fixture seat (3324), a high heat-conducting connecting seat (3325), and a mounting seat. One end of the high heat-conducting connecting seat (3325) is installed in the heat-insulating fixture seat (3324), and the high heat-conducting connecting seat (3325) and the heat-conducting upper cover (3322) respectively wrap the lower surface and the upper surface of the clamping end of the solid propellant specimen (333). A mounting seat is provided on one side of the heat-insulating fixture seat (3324) and is connected to the corresponding loading crossbeam (312) through the mounting seat. The load measurement assembly (331) includes a force sensor fixing plate (3311), a force sensor (3312), a fixture positioning plate (3313), a round nut (3314), and a hexagon lock nut (3315). The external thread of the small pitch end of the hexagon lock nut (3315) is connected to the mounting seat of one of the fixture assemblies (332), and the internal thread of the large pitch end of the hexagon lock nut (3315) is connected to one end of the force sensor (3312). The other end of the force sensor (3312) passes through the through hole on the force sensor fixing plate (3311) and is fixedly connected to the round nut (3314). The two ends of the fixture positioning plate (3313) are respectively connected to the force sensor fixing plate (3311) and the mounting seat.

4. The high-efficiency in-situ testing device for the thermo-mechanical coupling of solid propellants in a scanning electron microscope according to claim 3, characterized in that, The fixture assembly (332) further includes an anti-frost fixture cover (3321) mounted on the upper surface of the heat-conducting upper cover (3322).

5. The high-efficiency in-situ test device for the thermo-mechanical coupling of solid propellants in a scanning electron microscope according to claim 3, wherein The liquid circulation heat-conducting assembly (34) includes a heat input assembly (341), a heat-conducting support assembly (342), two sets of sliding and adhering heat-conducting assemblies (343), and a middle fixed heat-conducting assembly (344); The heat input assembly (341) includes a liquid circulation heat-conducting plate (3411), a heat-conducting plate fixing frame (3412), and a group of heat-conducting plate fixing chutes (3413) mounted on the heat-insulating mounting body (3421). A flow channel communicating with the vacuum bellows (322) is provided inside the liquid circulation heat-conducting plate (3411). The heat-conducting plate fixing frame (3412) for supporting the liquid circulation heat-conducting plate (3411) can slide up and down along the heat-conducting plate fixing chute (3413) and is fixed to the heat-conducting plate fixing chute (3413) by screws, and the liquid circulation heat-conducting plate (3411) is adhesively pressed and connected to the friction heat-conducting plate (3423) in the heat-conducting support assembly (342); The heat-conducting support assembly (342) includes a heat-insulating mounting body (3421), a heat-insulating chute (3422), and a friction heat-conducting plate (3423). The inner groove of the heat-insulating chute (3422) is inlaid and connected to the friction heat-conducting plate (3423), and the outer frame of the heat-insulating chute (3422) is threadedly connected to the internal positioning surface of the heat-insulating mounting body (3421); Each set of the sliding and attaching type heat conduction components (343) includes a sliding traction bracket (3431), a first sliding heat conduction block bracket (3432), a first pressing type slider (3433), a first optical rod bearing (3434), a sliding heat conduction cover (3435) and a sliding heat conduction seat (3436). The two sides of the first sliding heat conduction block bracket (3432) are respectively connected to the first pressing type slider (3433) and the sliding heat conduction seat (3436) by threads, pressing the sliding heat conduction seat (3436) against the surface of the friction heat conduction plate (3423). The friction heat conduction plate (3423) conducts heat to the sliding heat conduction seat (3436) and the middle sliding heat conduction seat (3441) in the middle fixed heat conduction component (344). The sliding traction bracket (3431) is fixedly connected to the first sliding heat conduction block bracket (3432) and the loading cross beam (312) respectively. The sliding heat conduction seat (3436) and the sliding heat conduction cover (3435) form a space for covering one end of the high heat conduction connection seat (3325) where the specimen is not clamped. The first optical rod bearing (3434) is connected to the lower surface of the first pressing type slider (3433) by threads and contacts the heat insulation sliding groove (3422). The middle fixed heat conduction component (344) includes a second sliding heat conduction block bracket, a second pressing type slider, a second optical rod bearing, a middle sliding heat conduction seat (3441), a middle heat conduction positioning block (3442) and a middle adjustable heat conduction plate (3443). The two sides of the second sliding heat conduction block bracket are respectively connected to the second pressing type slider and the middle sliding heat conduction seat (3441) by threads. The second optical rod bearing is connected to the lower surface of the second pressing type slider by threads and contacts the heat insulation sliding groove (3422). The middle sliding heat conduction seat (3441) is connected and matched with the middle heat conduction positioning block (3442) installed in the groove of the heat insulation installation main body (3421). The middle adjustable heat conduction plate (3443) is installed in the groove on the middle sliding heat conduction seat (3441), and the upper surface of the middle adjustable heat conduction plate (3443) contacts the solid propellant specimen (333).

6. The high-efficiency in-situ test device for the thermo-mechanical coupling of solid propellants in a scanning electron microscope according to claim 5, wherein, There is a gap between the high heat conduction connection seat (3325) and the sliding heat conduction cover (3435) and the sliding heat conduction seat (3436), and a vacuum heat conduction grease (3437) is filled in the gap.

7. The high-efficiency in-situ test device for the thermo-mechanical coupling of solid propellants in a scanning electron microscope according to claim 5 or 6, characterized in that, The heat input component (341) further includes a protective shell (3414) installed on the upper surface of the heat conduction plate fixed sliding groove (3413).

8. The high-efficiency in-situ testing device for the thermo-mechanical coupling of solid propellants in a scanning electron microscope according to claim 5 or 6, characterized in that, The vacuum circulation pipeline component (32) includes a pipeline fixing seat (321), a vacuum corrugated pipe (322), a vacuum pipeline joint (323) and a heat insulation connection seat (324). One end of the vacuum corrugated pipe (322) is communicated with the flow channel inside the liquid circulation heat conduction plate (3411) through the vacuum pipeline joint (323) and is fixedly connected to the heat insulation connection seat (324) through the pipeline fixing seat (321). The other end of the vacuum corrugated pipe (322) is communicated with the outer circulation pipeline (12) installed in the pipeline telescopic component (1).

9. The high-efficiency in-situ test device for the thermo-mechanical coupling of solid propellants in a scanning electron microscope according to claim 1 or 2, characterized in that, The pipeline expansion and contraction assembly (1) includes a cam-type telescopic pipeline assembly (11) and an outer circulation pipeline (12); The cam-type telescopic pipeline assembly (11) includes a locking nut (111), a sliding traction seat (112), a sliding guide post (113), a rotating cam (114) and a guide cylinder (115). The sliding guide post (113) is installed in the spiral groove of the rotating cam (114) and the linear groove of the guide cylinder (115) at the same time. And the sliding guide post (113) is threadedly connected to the sliding traction seat (112) located inside the rotating cam (114). The sliding traction seat (112) is axially fixedly connected to the circulation pipeline flange (123) in the outer circulation pipeline (12). The locking nut (111) is threadedly connected to the guide cylinder (115) to lock the relative positions of the rotating cam (114) and the guide cylinder (115); The outer circulation pipeline (12) includes a ferrule type pipe joint (121), a pipe passing through the flange (122) and a circulation pipeline flange (123). One end of the pipe passing through the flange (122) is communicated with the vacuum bellows (322), and the other end passes through the circulation pipeline flange (123) and then installs the ferrule type pipe joint (121).

10. The high-efficiency in-situ test device for thermo-mechanical coupling of solid propellants in a scanning electron microscope according to claim 9, wherein, The pipeline expansion and contraction assembly (1) further includes a disc type bellows (116) and a bellows flange (117). One end of the disc type bellows (116) is fixedly connected to the circulation pipeline flange (123), and the other end is connected to the bellows flange (117) by welding, and the bellows flange (117) is fixedly connected to the bevel rectangular flange (22).

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