Solid propellant mechanical properties testing device and method compatible with SEM and CT

Abstract

The present invention relates to a solid propellant mechanical property testing device and method that is compatible with SEM and CT, and belongs to the technical field of precision scientific instruments and material microscopic mechanical property testing. It solves the problem of incomplete and inaccurate acquisition of propellant microscopic failure information in the prior art due to the single imaging device and the deterioration of image quality due to creep accumulation. In the mechanical property testing device, an in-situ mechanical testing device mechanically loads and holds the propellant sample, an SEM obtains the surface morphology of the propellant sample, a dual-source dual-detection industrial CT obtains the internal three-dimensional structure of the propellant sample, the in-situ mechanical testing device is transferred between the main cavity of the transfer cabin and the electron microscope cabin through a transfer channel, and a robotic arm transports the vacuum transfer cabin containing the in-situ mechanical testing device between the transfer channel and the scanning turntable of the dual-source dual-detection industrial CT. The present invention can ensure that more comprehensive and accurate microscopic failure information of the propellant sample is obtained while paying less time cost.

Description

Technical Field

[0001] The present invention relates to the technical field of precision scientific instruments and material micromechanical properties testing, and in particular to a solid propellant mechanical properties testing device and method compatible with SEM and CT. Background Art

[0002] In the research and development of solid propellants, in-situ testing of mechanical properties is a key step in evaluating their reliability and stability. Scanning Electron Microscope (SEM), as a high-resolution imaging technology, is widely used for observing surface morphology. It can provide very detailed images of the sample surface structure, which are used to analyze the microscopic features of the material surface. Computed Tomography (CT) is a non-destructive imaging technology based on X-rays that can provide three-dimensional images of the internal structure of the sample. Based on the above characteristics, a variety of in-situ mechanical property testing devices compatible with scanning electron microscopes or Micro-CT have been developed both domestically and internationally, but these devices are only compatible with one type of imaging device.

[0003] SEM and CT, two imaging technologies, each have their own advantages and disadvantages, and it is difficult to quickly and simultaneously obtain complete information about the propellant sample in the same test. SEM can only obtain surface information of the sample and cannot reveal the internal structural characteristics of the sample, especially when observing internal defects and microcracks of the sample. CT technology is suitable for revealing macroscopic defects inside the sample, such as pores, cracks, etc. However, CT requires a long time for scanning and imaging. For propellants in the process of mechanical loading, during long-term and multiple CT scanning imaging, the propellant is prone to obvious creep accumulation effects, resulting in serious image overlap in the acquired three-dimensional images, and it is impossible to obtain true three-dimensional morphological information. Therefore, using SEM or CT alone often cannot fully reflect the micromechanical properties of the propellant sample.

[0004] If the surface morphology information and internal three-dimensional structural characteristics of solid propellants under mechanical loads can be collected simultaneously and in situ, and the obtained surface morphology changes and internal damage evolution can be combined for comprehensive analysis, it will be important for comprehensively revealing the mechanism between the macroscopic mechanical properties and microscopic damage, failure, and deformation of the propellant at multiple levels and dimensions. Therefore, it is of great significance to study the solid propellant mechanical property testing equipment and testing methods that are synchronously compatible with SEM and CT. Summary of the Invention

[0005] The purpose of the present invention is to provide a solid propellant mechanical property testing device and method compatible with SEM and CT, so as to solve the problem of incomplete and inaccurate acquisition of propellant microscopic failure information due to the single imaging equipment and the deterioration of image quality due to creep accumulation in the above-mentioned prior art. The present invention constructs a connection channel between the scanning electron microscope and the dual-source dual-detection industrial CT through a vacuum transfer cabin and a transfer channel, and adjusts the sample angle through two sets of synchronously rotating rotatable clamps. It can simultaneously meet the various imaging angles required by different imaging modes of the scanning electron microscope and the requirement that the sample rotates with the scanning angle during the scanning process of the dual-source dual-detection industrial CT, and can quickly and completely obtain the surface and internal deformation and damage forms of the propellant sample during the entire loading process, providing a key technical means for scientifically constructing the relationship between the microscopic organizational evolution and the dynamic response of the macroscopic performance of the solid propellant from the surface to the inside under complex loads.

[0006] In order to achieve the above object, the present invention adopts the following scheme:

[0007] Solid propellant mechanical properties testing device compatible with SEM and CT, including:

[0008] A scanning electron microscope is provided with a transfer channel connected to an electron microscope cabin of the scanning electron microscope for obtaining surface morphology information of the propellant sample;

[0009] Dual-source, dual-detection industrial CT, used to obtain internal 3D structural information of propellant samples;

[0010] The vacuum transfer chamber includes a transfer chamber door, a main chamber, a transfer chamber scanning window bracket, and a high-transparency scanning window. The interior of the main chamber is provided with a movable platform for transmitting an in-situ mechanical testing device. The high-transparency scanning window is mounted on the side wall of the main chamber via the transfer chamber scanning window bracket. The transfer chamber door is connected to the front end of the main chamber and is used to control the connection and isolation between the main chamber and the transfer channel.

[0011] A robotic arm is used to transport a vacuum transfer chamber containing an in-situ mechanical testing device between a docking position of the transfer channel and a scanning turntable of a dual-source dual-detection industrial CT according to a predetermined spatial motion trajectory, and the vacuum transfer chamber maintains a high vacuum environment during the transport process;

[0012] The transfer channel is equipped with a vacuum pneumatic gate valve for controlling the connection and isolation of the transfer channel, and is used to transfer the in-situ mechanical testing device between the main cavity of the transfer cabin and the electron microscope cabin;

[0013] The in-situ mechanical testing device includes a bidirectional mechanical loading platform and two sets of rotatable clamps installed on the bidirectional mechanical loading platform. The two ends of the propellant sample are fixedly clamped on the two rotatable clamps respectively. The two sets of rotatable clamps, in cooperation with the bidirectional mechanical loading platform, synchronously perform stretching and / or rotational actions in accordance with the scanning imaging rhythm of the scanning electron microscope and the dual-source dual-detection industrial CT, including synchronous co-directional rotation, synchronous counter-rotation, asynchronous co-directional rotation, and asynchronous counter-rotation, to mechanically load and maintain the propellant sample.

[0014] At the same time, the present invention also proposes a solid propellant mechanical property testing method compatible with SEM and CT, which includes the following steps:

[0015] S1: The robotic arm transfers the vacuum transfer chamber to the docking position of the transfer channel, opens the transfer chamber door and the vacuum pneumatic valve, connects the vacuum transfer chamber to the scanning electron microscope, and reduces the vacuum level of the scanning electron microscope, the transfer channel, and the vacuum transfer chamber to the preset vacuum level and maintains it;

[0016] S2: Determine the loading mode for the mechanical property test of the propellant sample. If it is an in-situ tensile test, set the active frameless torque motor and the slave torque motor to a master-slave follower mode; if it is a tensile-torsion test, control the active frameless torque motor and the slave torque motor to operate independently.

[0017] S3: Turn on the electron gun of the scanning electron microscope and locate the test target area of ​​the propellant sample;

[0018] S4: Setting the loading parameters for the mechanical properties test, the in-situ mechanical testing device completes the target parameter loading and maintains the load without unloading;

[0019] S5: Determine whether it is a SEM / EDS / DIC test. If so, the active frameless torque motor and the driven torque motor synchronously rotate the two sets of rotatable fixtures in the same direction to a first deflection angle state. If not, continue to determine whether it is an EBSD test. If so, the active frameless torque motor and the driven torque motor adjust the two sets of rotatable fixtures to a second deflection angle state. After the imaging angle is adjusted, the scanning electron microscope obtains microscopic morphological information of the surface of the test target area.

[0020] S6: Determine whether the mechanical property test in the scanning electron microscope is complete. If so, transfer the in-situ mechanical testing device to the vacuum transfer chamber through the transfer channel. The propellant sample is then transported to the bottom of the high-transmittance scanning window via the mobile platform inside the vacuum transfer chamber. The transfer chamber door and the vacuum pneumatic gate valve are closed in sequence. After the vacuum in the low-vacuum section transfer channel is vented, the robotic arm transports the vacuum transfer chamber to the scanning turntable in the dual-source dual-detection industrial CT.

[0021] S7: Synchronously control the scanning frequency of the X-ray source in the dual-source dual-detection industrial CT and the rotation speed of two sets of rotatable fixtures in the in-situ mechanical testing device. The X-rays emitted by the X-ray source penetrate the high-transmittance scanning window and the propellant sample before irradiating the CT detector, obtaining internal 3D structural information of the propellant sample during the rotational scanning process.

[0022] S8: After the dual-source dual-detector industrial CT scanning and imaging is completed, it is determined whether the mechanical property test in the dual-source dual-detector industrial CT is completed. If so, the robotic arm transfers the vacuum transfer cabin to dock with the transfer channel on the scanning electron microscope, opens the transfer cabin door and the vacuum pneumatic gate valve, establishes a vacuum channel between the vacuum transfer cabin, the transfer channel and the scanning electron microscope, and transports the in-situ mechanical testing device into the scanning electron microscope through the transfer channel;

[0023] S9: Determine whether the combined mechanical property test in the scanning electron microscope and the dual-source dual-detection industrial CT is completed. If so, release the vacuum of the scanning electron microscope and replace the propellant sample; if not, return to step S3 until the combined mechanical property test is completed.

[0024] The present invention has the following beneficial effects compared to the prior art:

[0025] The present invention addresses the shortcomings of existing in-situ mechanical property testing devices that are only compatible with a single scanning electron microscope or CT, which can only obtain surface information at a short sampling time and internal information at a longer sampling time during testing, but the image quality is poor due to creep. A propellant mechanical property testing device and testing method that are synchronously compatible with both a scanning electron microscope and a CT are provided. During the mechanical loading and holding process, the in-situ mechanical testing device is enclosed in a vacuum transfer chamber. Utilizing the flexibility and convenience of a robotic arm, the in-situ mechanical testing device can be quickly transferred between the scanning electron microscope and the dual-source dual-detection industrial CT. The sealed vacuum transfer chamber avoids the number and time of repeated vacuuming of the scanning electron microscope when the in-situ mechanical testing device switches imaging devices. The two sets of rotatable clamps in the testing device can adjust the imaging angle of the propellant sample according to the different imaging modes of the scanning electron microscope, and can also adjust the angle of the propellant sample in real time according to the scanning frequency of the radiation source in the dual-source dual-detection industrial CT. The testing device and testing method designed by the present invention can set the optimal sampling time interval and number ratio for image acquisition using a scanning electron microscope and a CT. Leveraging the rapid imaging capabilities of scanning electron microscopy, a large amount of surface morphology information is obtained. Simultaneously, utilizing the CT scanning capability to obtain information on the internal three-dimensional structure of the specimen, a small amount of internal structural damage evolution is precisely captured within the surface failure region. While fully capturing both the surface and internal failure patterns of the propellant specimen, the effects of stress relaxation on its mechanical properties are effectively avoided, ensuring the accuracy of material mechanical property testing. This provides a novel and effective technical approach for scientifically establishing the relationship between the microscopic structural evolution and the dynamic response of the macroscopic mechanical properties of propellants under complex loads. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 Schematic diagram of the overall structure of the solid propellant mechanical properties testing device compatible with SEM and CT according to an embodiment of the present invention;

[0028] Figure 2 for Figure 1 A partial enlarged diagram of the middle 1A area after removing the transfer cabin scanning window bracket and high-transmittance scanning window;

[0029] Figure 3 Schematic diagram of the overall structure of the in-situ mechanical testing device;

[0030] Figure 4 for Figure 3 Internal cross-sectional view of area 7A;

[0031] Figure 5 Schematic diagram of the overall structure of the in-situ mechanical testing device for microscopic imaging and transfer transportation in SEM;

[0032] Figure 6 for Figure 5 A partial enlarged schematic diagram of the middle 4A area;

[0033] Figure 7 This is a schematic diagram of the overall structure of the in-situ mechanical testing device in the vacuum transfer chamber;

[0034] Figure 8 Schematic diagram of the in-situ mechanical testing device combined with dual-source dual-detection industrial CT for three-dimensional imaging;

[0035] Figure 9 This is a flow chart of a solid propellant mechanical property testing method compatible with SEM and CT according to another embodiment of the present invention.

[0036] Description of reference numerals:

[0037] 1. Vacuum transfer chamber; 101. Transfer chamber door; 102. Transfer chamber main chamber; 103. Transfer chamber X-axis moving platform; 104. Transfer chamber Y-axis moving platform; 105. Transfer chamber scanning window bracket; 106. High-transparency scanning window;

[0038] 2. Transfer channel; 201, high vacuum section transfer channel; 202, low vacuum section transfer channel;

[0039] 3. Vacuum pneumatic gate valve;

[0040] 4. Scanning electron microscope; 401. EBSD detector; 402. EDS detector; 403. Pole shoe;

[0041] 5. Dual-source dual-detector industrial CT; 51. CT detector; 52. Scanning turntable; 53. X-ray source; 531. Microfocus X-ray source;

[0042] 6. Robotic arm;

[0043] 7. In-situ mechanical testing device; 701. Loading beam; 702. Bidirectional trapezoidal lead screw; 703. Active frameless torque motor; 7031. Motor hollow rotor; 7032. Motor stator; 7033. Motor stator mounting base; 704. Encoder; 705. Slip ring; 706. Force sensor; 7061. Force sensor force measuring body; 7062. Force sensor signal line; 707. Needle roller bearing; 708. Active fixture head; 709. Propellant sample; 710. Driven fixture head; 711. Thrust ball bearing; 712. Driven torque motor. DETAILED DESCRIPTION

[0044] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0045] like Figures 1 to 8 As shown, this embodiment provides a solid propellant mechanical property testing device compatible with SEM and CT, which includes a vacuum transfer cabin 1, a transfer channel 2, a scanning electron microscope 4, a dual-source dual-detection industrial CT 5, a robotic arm 6 and an in-situ mechanical testing device 7.

[0046] The scanning electron microscope 4 is used to obtain surface morphology information of the propellant sample 709 , and a transfer channel 2 communicating with the electron microscope cabin is provided on a side wall of the electron microscope cabin of the scanning electron microscope 4 .

[0047] The dual-source, dual-detection industrial CT5 is used to obtain the internal three-dimensional structure information of the propellant sample 709.

[0048] Furthermore, the dual-source, dual-detector industrial CT system 5 in this embodiment includes a frame, a CT detector 51, a scanning turntable 52, and a radiation source 53 mounted on the frame. The scanning turntable 52, which supports the sample, is located between the CT detector 51 and the radiation source 53. The CT detector 51 and the radiation source 53 are symmetrically arranged relative to the scanning turntable 52. When the vacuum transfer chamber 1 containing the in-situ mechanical testing device 7 is positioned on the scanning turntable 52, the mobile platform within the main chamber 102 of the transfer chamber moves the propellant sample 709 clamped in the in-situ mechanical testing device 7 to below the high-transmittance scanning window 106. This allows the X-rays emitted by the radiation source 53 to penetrate the high-transmittance scanning window 106 and the propellant sample 709 and irradiate the CT detector 51, presenting clear microstructural information on the CT detector 51. Optionally, the radiation source 53 can be a microfocus radiation source 531 to further improve scanning resolution and reduce creep accumulation.

[0049] The vacuum transfer cabin 1 includes a transfer cabin door 101, a transfer cabin main cavity 102, a transfer cabin scanning window bracket 105 and a high-transmittance scanning window 106, wherein the interior of the transfer cabin main cavity 102 is provided with a movable platform for transmitting the in-situ mechanical testing device 7, including a transfer cabin X-direction movable platform 103 and a transfer cabin Y-direction movable platform 104. The high-transmittance scanning window 106 is installed on the side wall of the transfer cabin main cavity 102 through the transfer cabin scanning window bracket 105. The transfer cabin door 101 is connected to the front end of the transfer cabin main cavity 102 and is used to control the combination and isolation of the transfer cabin main cavity 102 and the transfer channel 2. Among them, the transfer cabin X-direction moving platform 103 and the transfer cabin Y-direction moving platform 104 have the same structure, and their interiors are composed of servo motors, linear guides, trapezoidal screws, movable base plates, etc., and their connection and operation principles are as follows: the servo motor is connected to the trapezoidal screw, and the movable base plate is installed on the trapezoidal screw and the linear guide rails. The servo motor rotates to drive the trapezoidal screw to rotate, and then drives the movable base plate to slide along the linear guide rails. The transfer cabin X-direction moving platform 103 and the transfer cabin Y-direction moving platform 104 are used in combination, and under the control of the system control and data acquisition and processing unit, the in-situ mechanical testing device 7 can be moved in the main cavity 102 of the transfer cabin. The X-direction and Y-direction in the transfer cabin X-direction moving platform 103 and the transfer cabin Y-direction moving platform 104 are the same as Figure 1 The x-axis and y-axis in the xyz coordinate system are in the same direction, where the x-axis is along the length direction of the dual-source dual-detection industrial CT5, the y-axis is along the width direction of the dual-source dual-detection industrial CT5, and the z-axis is along the height direction of the dual-source dual-detection industrial CT5.

[0050] The robotic arm 6 is used to transport the vacuum transfer chamber 1 containing the in-situ mechanical testing device 7 between the docking position of the transfer channel 2 and the scanning turntable 52 of the dual-source dual-detection industrial CT5 according to a predetermined spatial motion trajectory, and the vacuum transfer chamber 1 maintains a high vacuum environment during the transportation process. The transportation process of the in-situ mechanical testing device 7 is achieved while keeping the propellant sample 709 in a high vacuum and stable mechanical load.

[0051] As an optional way to achieve the connection between the robotic arm 6 and the vacuum transfer cabin 1, a suction cup is installed at the end of the robotic arm 6. The suction cup is connected to the side wall of the vacuum transfer cabin 1 using the vacuum negative pressure principle, thereby achieving a stable connection to the vacuum transfer cabin 1 during the transportation of the vacuum transfer cabin 1.

[0052] The transfer channel 2 is provided with a vacuum pneumatic gate valve 3 for controlling the connection and isolation of the transfer channel 2, and is used to transfer the in-situ mechanical testing device 7 between the transfer chamber main cavity 102 and the electron microscope chamber. The vacuum transfer chamber 1 is connected to the electron microscope chamber of the scanning electron microscope 4 through the vacuum pneumatic gate valve 3 and the transfer channel 2. The vacuum pneumatic gate valve 3 divides the transfer channel 2 into a high vacuum section transfer channel 201 and a low vacuum section transfer channel 202. The high vacuum section transfer channel 201 is directly connected to the electron microscope chamber, while the vacuum level of the low vacuum section transfer channel 202 is regulated by the vacuum pneumatic gate valve 3. The vacuum pneumatic gate valve 3 can establish a channel between the low vacuum section transfer channel 202 and the high vacuum section transfer channel 201. The in-situ mechanical testing device 7 can be transported from the electron microscope chamber to the vacuum transfer chamber 1 or from the vacuum transfer chamber 1 to the electron microscope chamber via the transfer channel 2.

[0053] The in-situ mechanical testing apparatus 7 is used to apply tensile and / or rotational mechanical loads to a solid propellant sample 709 and measure the load magnitude. Specifically, the apparatus comprises a bidirectional mechanical loading platform and two sets of rotatable fixtures mounted on the platform. The two sets of rotatable fixtures can rotate synchronously in the same direction, synchronously in opposite directions, asynchronously in the same direction, or asynchronously in opposite directions around a common axis of the fixtures during loading on the platform. The propellant sample 709 is fixedly clamped at both ends on the two rotatable fixtures. In conjunction with the bidirectional mechanical loading platform, the two sets of rotatable fixtures can synchronize tensile and / or rotational movements with the scanning imaging rhythm of the scanning electron microscope 4 and the dual-source dual-detection industrial CT 5. The rotational movements can be any of synchronous co-directional rotation, synchronous counter-rotation, asynchronous co-directional rotation, and asynchronous counter-rotation, thereby mechanically loading and maintaining the propellant sample 709. The scanning imaging cycle of the scanning electron microscope 4 and the dual-source dual-detection industrial CT 5 refers to the pre-defined imaging steps and timing during the solid propellant mechanical property testing process. For example, the in-situ mechanical testing device 7 first stretches the propellant sample 709. After the stretching stops, the mechanical load is maintained and the scanning electron microscope is used to image it. After the image is obtained, the in-situ mechanical testing device 7 is transferred to the dual-source dual-detection industrial CT 5 (the mechanical load remains unchanged). The rotatable fixture in the in-situ mechanical testing device 7 rotates at a set rotation speed. The dual-source dual-detection industrial CT 5 obtains a complete image of the propellant sample 709 for one rotation according to the set CT imaging time. After the CT imaging is completed, the in-situ mechanical testing device 7 is transferred to the scanning electron microscope. The in-situ mechanical testing device 7 again stretches and loads the propellant sample 709. After the loading is completed, the scanning electron microscope is used to image it. This completes a complete imaging process including multiple scanning imaging cycles. The specific scanning imaging cycle varies according to the requirements of the mechanical property testing and is not limited here.

[0054] The bidirectional mechanical loading platform includes a bidirectional trapezoidal screw 702 and two loading beams 701 threadedly engaged with the bidirectional trapezoidal screw 702. Two sets of rotatable clamps are respectively connected to the two loading beams 701. The bidirectional trapezoidal screw 702 drives the loading beam 701 to drive the rotatable clamps thereon to perform tensile movement, thereby realizing tensile loading of the propellant sample 709.

[0055] Furthermore, the two sets of rotatable fixtures are divided into an active rotary tensile fixture and a passive rotary tensile fixture. The active rotary tensile fixture includes an active frameless torque motor 703, a large-aperture encoder 704, a slip ring 705, a force sensor 706, a needle roller bearing 707, a thrust ball bearing, and an active fixture head 708. The active frameless torque motor 703 includes a hollow rotor 7031, a stator 7032, and a stator mounting base 7033. The force sensor 706 includes a force sensor body 7061 and a force sensor signal line 7062. One end of the force sensor body 7061 is connected to the motor hollow rotor 7031, which is connected to the corresponding loading beam 701 via a thrust ball bearing. The force sensor signal line 7062 passes through the motor hollow rotor 7031 and is connected to a slip ring 705 mounted at the end of the encoder 704. This signal line extends from the rear of the sensor and, in conjunction with the slip ring design, prevents the signal line from being torn due to excessive winding during fixture rotation. The motor stator 7032 is mounted on the motor stator fixing base 7033, and the encoder 704 is connected to the motor stator fixing base 7033 to measure the rotation angle of the motor hollow rotor 7031. The other end of the force sensor body 7061 is fixed to the active fixture head and connected to the corresponding loading beam 701 via a needle bearing 707. The driven rotary tensile fixture includes a driven torque motor 712, a thrust ball bearing 711, and a driven fixture head 710 connected in sequence, and the thrust ball bearing 711 is connected to the corresponding loading beam 701. The active rotary tensile fixture is connected to the corresponding loading beam 701 via a needle roller bearing 707 and a thrust ball bearing, and the driven rotary tensile fixture is connected to the corresponding loading beam 701 via a thrust ball bearing 711. The needle roller bearing 707 can ensure that the active rotary tensile fixture has a fixed position in the circumferential direction, but can move in the axial direction, while the thrust ball bearing 711 can limit the axial movement of the active and driven rotary tensile fixtures, but can ensure their rotation in the circumferential direction. The two can be used together to ensure that the two sets of rotatable fixtures can rotate in the circumferential direction without axial movement during the tensile loading process, thereby ensuring the coaxiality and axial position between the two sets of rotatable fixtures.

[0056] This embodiment provides a solid propellant mechanical properties testing device compatible with both SEM and CT. The device includes an in-situ mechanical testing device 7 for mechanically loading and holding a propellant sample 709. After obtaining surface morphology information of the propellant sample 709 using a scanning electron microscope 4, the held in-situ mechanical testing device 7 is transferred to a vacuum transfer chamber 1 via a transfer channel 2 on the wall of the electron microscope chamber. A robotic arm then transports the vacuum transfer chamber 1, separated from the transfer channel 2, to the scanning turntable of a dual-source, dual-detection industrial CT 5 according to a predetermined spatial motion trajectory. The two sets of rotatable fixtures of the in-situ mechanical testing device 7 in the vacuum transfer chamber 1 rotate synchronously (or synchronously, asynchronously, or asynchronously) with the scanning frequency of the radiation source in the dual-source, dual-detection industrial CT 5 to obtain internal three-dimensional structural information of the propellant sample 709 during mechanical loading. Afterwards, the in-situ mechanical testing device 7 can be transferred to the transfer channel 2 again, and finally transported to the electron microscope cabin of the scanning electron microscope 4 through the transfer channel 2. The in-situ mechanical testing device 7 continuously performs mechanical loading on the propellant sample 709 and performs scanning electron microscope 4 imaging as needed. This process is repeated repeatedly. By continuously adjusting the working state between the in-situ mechanical testing device 7 and the microscopic imaging equipment, repeatable testing can be achieved, ensuring that more comprehensive and accurate microscopic failure information of the propellant sample 709 is obtained with less time cost.

[0057] like Figure 9 As shown, another embodiment of the present invention provides a method for testing the mechanical properties of solid propellants using both SEM and CT. This method, based on the testing apparatus described in the previous embodiment, enables SEM and CT to obtain microstructural failure forms of propellant samples in the same state. Specifically, this method includes the following steps S1-S9.

[0058] S1: The robotic arm 6 transfers the vacuum transfer chamber 1 to the docking position of the transfer channel 2, opens the corresponding vacuum valves (the transfer chamber door 101 and the vacuum pneumatic gate valve 3), connects the vacuum transfer chamber 1 with the scanning electron microscope 4 through the transfer channel 2, and reduces the vacuum level of the scanning electron microscope 4, the transfer channel 2, and the vacuum transfer chamber 1 to a preset vacuum level, for example, 0.025 Pa to 0.055 Pa, and maintains the vacuum level.

[0059] S2: Determine the loading mode of the propellant sample mechanical property test and judge whether it is an in-situ tensile test. If it is an in-situ tensile test, set the active frameless torque motor 703 and the slave torque motor 712 to a master-slave follower mode; if it is a tensile-torsion test, set the active frameless torque motor 703 and the slave torque motor 712 to operate independently;

[0060] S3: Turn on the electron gun of the scanning electron microscope 4 and locate the test target area of ​​the propellant sample 709;

[0061] S4: The loading parameters of the mechanical property test of the in-situ mechanical testing device 7 are set through the system control and data acquisition processing unit, including parameters such as tensile loading speed, single tensile displacement, and overall tensile displacement. The in-situ mechanical testing device 7 completes the target parameter loading and keeps the load from being unloaded. The system control and data acquisition processing unit is used to control the operation of the motor in the entire solid propellant mechanical property testing device, the position movement of the in-situ mechanical testing device 7 in the scanning electron microscope 4, the movement in the transfer channel 2, the movement in the vacuum transfer cabin 1, the adsorption and bonding of the robotic arm 6 and the vacuum transfer cabin 1, the motion trajectory of the robotic arm 6, and the rotational movement of the scanning turntable 52, and can collect the tensile force value and displacement information in the in-situ mechanical testing device 7, as well as the status information of the movement and conversion between the scanning electron microscope 4 and the dual-source dual-detection industrial CT 5, etc.

[0062] S5: Adjust the imaging angle of the propellant sample 709. First, determine whether it is SEM / EDS / DIC testing. If so, the active frameless torque motor 703 and the driven torque motor 712 rotate the two sets of rotatable fixtures synchronously and in the same direction to a first deflection state, such as a 0° deflection state (e.g., Figure 3 As shown); if not, continue to determine whether it is an EBSD test. If it is an EBSD test, the active frameless torque motor 703 and the driven torque motor 712 adjust the two sets of rotatable clamps to a second deflection state, for example, a 70° deflection state. After adjusting the imaging angle, the scanning electron microscope 4 is used to obtain the microscopic morphology information of the target area surface; wherein, the deflection angle of the two sets of rotatable clamps refers to the angle between the upper surface of the active clamp head 708 and the driven clamp head 710 in the two sets of rotatable clamps and the upper surface of the loading beam 701. When the upper surfaces of the two are parallel, it is a 0° deflection state, and when the angle between the two planes is 70°, it is a 70° deflection state.

[0063] S6: Determine the content of the microstructure information obtained, judge whether the information obtained by the scanning electron microscope 4 is complete based on the test requirements and imaging effects, and perform a CT imaging test, that is, judge whether the mechanical property test in the scanning electron microscope 4 is completed. If completed, the in-situ mechanical testing device 7 is transferred to the vacuum transfer chamber 1 through the transfer channel 2, and the propellant sample 709 is transported to the bottom of the high-transmittance scanning window 106 through the mobile platform inside the vacuum transfer chamber 1, and the transfer chamber door 101 and the vacuum pneumatic plug valve 3 are closed in turn. After the vacuum in the low-vacuum section transfer channel 202 is released, the robotic arm 6 transports the vacuum transfer chamber 1 to the center of the scanning turntable 52 in the dual-source dual-detection industrial CT 5; if further mechanical property test information of the propellant sample 709 needs to be obtained, the propellant sample 709 is further loaded and then returns to step S4, and steps S4 to S6 are repeated until the mechanical property test in the scanning electron microscope 4 is completed;

[0064] S7: Synchronously controlling the scanning frequency of the radiation source 53 in the dual-source dual-detection industrial CT 5 and the rotational speed of the two sets of fixtures in the in-situ mechanical testing device 7. The X-rays emitted by the radiation source 53 penetrate the high-transmittance scanning window 106 and the propellant sample 709 and then irradiate the CT detector 51, thereby obtaining the internal three-dimensional structural information of the propellant sample 709 during the rotational scanning process.

[0065] S8: After the dual-source dual-detection industrial CT5 scans and images, it is determined whether the acquired mechanical test data is complete, that is, whether the mechanical property test in the dual-source dual-detection industrial CT5 is completed. If completed, the robotic arm 6 docks the vacuum transfer cabin 1 with the transfer channel 2 on the scanning electron microscope 4, opens the transfer cabin door 101 and the vacuum pneumatic gate valve 3, establishes a vacuum channel between the vacuum transfer cabin 1, the transfer channel 2 and the scanning electron microscope 4, and transports the in-situ mechanical testing device 7 through the transfer channel 2 to the electron microscope cabin of the scanning electron microscope 4; if not completed, returns to step S7;

[0066] S9: Determine the progress of the in-situ mechanical property test in the scanning electron microscope 4 and the dual-source dual-detection industrial CT5, and judge whether the joint mechanical property test in the scanning electron microscope 4 and the dual-source dual-detection industrial CT5 is completed. If completed, release the vacuum of the scanning electron microscope 4 and replace the propellant sample 709; if it is necessary to continue to obtain the morphological information of the propellant sample 709, return to step S3, repeat steps S3 to S9 until the joint mechanical property test is completed and end after obtaining complete test information.

[0067] The present invention provides a propellant mechanical property testing device and testing method that are synchronously compatible with scanning electron microscopes and CT. During the mechanical loading and holding process, the in-situ mechanical testing device is wrapped in a vacuum transfer chamber. By utilizing the flexibility and convenience of the robotic arm, the in-situ mechanical testing device can be quickly transferred between the scanning electron microscope and the dual-source dual-detection industrial CT. The sealed vacuum transfer chamber avoids the number and time of repeated vacuuming of the scanning electron microscope when the in-situ mechanical testing device switches the imaging device. The two sets of rotatable clamps in the testing device can adjust the imaging angle of the propellant sample according to the different imaging modes of the scanning electron microscope, and can also adjust the angle of the propellant sample in real time according to the scanning frequency of the radiation source in the dual-source dual-detection industrial CT. Through the testing device and testing method designed by the present invention, the optimal sampling time interval and number ratio for image acquisition using a scanning electron microscope and CT can be set. By utilizing the fast imaging characteristics of the scanning electron microscope, a large amount of sample surface morphology information can be obtained. At the same time, by utilizing the characteristics of the CT scanning that the internal three-dimensional structure information of the sample can be obtained, only a small amount of internal structural damage evolution form of the surface failure area can be accurately obtained. While fully obtaining the surface and internal failure forms of the propellant sample, the influence of stress relaxation on the mechanical properties of the propellant sample is effectively avoided, ensuring the accuracy of the material mechanical properties test, and providing a more novel and effective technical means for scientifically establishing the relationship between the microscopic structural evolution and the dynamic response of the macroscopic mechanical properties of the propellant under complex loads.

[0068] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0069] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A solid propellant mechanical properties testing device compatible with SEM and CT, characterized by: include: A scanning electron microscope (4) is provided with a transfer channel (2) connected to an electron microscope cabin of the scanning electron microscope (4) for obtaining surface morphology information of a propellant sample (709); Dual-source dual-detection industrial CT (5) for obtaining internal three-dimensional structural information of the propellant sample (709); A vacuum transfer cabin (1) comprises a transfer cabin door (101), a transfer cabin main cavity (102), a transfer cabin scanning window bracket (105) and a high-transmittance scanning window (106), wherein a mobile platform for transmitting an in-situ mechanical testing device (7) is provided inside the transfer cabin main cavity (102), and the high-transmittance scanning window (106) is mounted on the side wall of the transfer cabin main cavity (102) through the transfer cabin scanning window bracket (105), and the transfer cabin door (101) is connected to the front end of the transfer cabin main cavity (102) and is used to control the combination and isolation of the transfer cabin main cavity (102) and the transfer channel (2); A robotic arm (6) is used to transfer a vacuum transfer chamber (1) containing an in-situ mechanical testing device (7) between a docking position of a transfer channel (2) and a scanning turntable (52) of a dual-source dual-detection industrial CT (5) according to a predetermined spatial motion trajectory, and the vacuum transfer chamber (1) maintains a high vacuum environment during the transfer process; A transfer channel (2) is provided with a vacuum pneumatic gate valve (3) for controlling the connection and isolation of the transfer channel (2), and is used to transfer the in-situ mechanical testing device (7) between the transfer cabin main cavity (102) and the electron microscope cabin; The in-situ mechanical testing device (7) comprises a bidirectional mechanical loading platform and two sets of rotatable clamps mounted on the bidirectional mechanical loading platform, wherein both ends of the propellant sample (709) are fixedly clamped on the two rotatable clamps respectively. The two sets of rotatable clamps, in cooperation with the bidirectional mechanical loading platform, synchronously perform stretching and / or rotational actions in accordance with the scanning imaging rhythm of the scanning electron microscope and the dual-source dual-detection industrial CT, including synchronous same-direction rotation, synchronous counter-rotation, asynchronous same-direction rotation, and asynchronous counter-rotation, to mechanically load and maintain the propellant sample (709).

2. The solid propellant mechanical properties testing device compatible with SEM and CT according to claim 1, characterized in that: The bidirectional mechanical loading platform comprises a bidirectional trapezoidal screw (702) and two loading beams (701) threadedly engaged with the bidirectional trapezoidal screw (702); The two sets of rotatable clamps are respectively connected to the two loading beams (701), and the bidirectional trapezoidal lead screw (702) drives the loading beam (701) to drive the rotatable clamps thereon to perform stretching movement.

3. The solid propellant mechanical properties testing device compatible with SEM and CT according to claim 1 or 2, characterized in that: The two sets of rotatable fixtures are divided into an active rotary stretching fixture and a driven rotary stretching fixture, wherein the active rotary stretching fixture includes an active frameless torque motor (703), an encoder (704), a slip ring (705), a force sensor (706), a needle roller bearing (707), a thrust ball bearing and an active fixture head (708), the active frameless torque motor (703) includes a motor hollow rotor (7031), a motor stator (7032) and a motor stator fixing seat (7033), the force sensor (706) includes a force sensor force measuring body (7061) and a force sensor signal line (7062), one end of the force sensor force measuring body (7061) is connected to the motor hollow rotor In (7031), the motor hollow rotor (7031) is connected to the corresponding loading beam (701) through a thrust ball bearing, the force sensor signal line (7062) passes through the motor hollow rotor (7031) and is connected to a slip ring (705) installed at the end of the encoder (704), the motor stator (7032) is installed on the motor stator fixing seat (7033), the encoder (704) is connected to the motor stator fixing seat (7033), the other end of the force sensor force measuring body (7061) is fixed to the active fixture head (708), and the force sensor force measuring body (7061) is connected to the corresponding loading beam (701) through a needle bearing (707); The driven rotary stretching fixture comprises a driven torque motor (712), a thrust ball bearing (711), and a driven fixture head (710) connected in sequence, and the thrust ball bearing (711) is connected to a corresponding loading beam (701).

4. The solid propellant mechanical properties testing device compatible with SEM and CT according to claim 1 or 2, characterized in that: The dual-source dual-detection industrial CT (5) includes a frame and a CT detector (51), a scanning turntable (52) and a radiation source (53) arranged on the frame, and the CT detector (51) and the radiation source (53) are symmetrically arranged relative to the scanning turntable (52). When the vacuum transfer cabin (1) containing the in-situ mechanical testing device (7) is located on the scanning turntable (52), the moving platform in the main cavity (102) of the transfer cabin moves the propellant sample (709) clamped in the in-situ mechanical testing device (7) to the bottom of the high-transmittance scanning window (106), so that the X-rays emitted by the radiation source (53) penetrate the high-transmittance scanning window (106) and the propellant sample (709) and irradiate the CT detector (51).

5. The solid propellant mechanical properties testing device compatible with SEM and CT according to claim 4, characterized in that: The ray source (53) adopts a micro-focus ray source.

6. The solid propellant mechanical properties testing device compatible with SEM and CT according to claim 1 or 2, characterized in that: The vacuum pneumatic plug-in valve (3) divides the transfer channel (2) into a high vacuum section transfer channel (201) and a low vacuum section transfer channel (202), wherein the high vacuum section transfer channel (201) is directly connected to the electron microscope cabin, and the vacuum degree of the low vacuum section transfer channel (202) is regulated by the vacuum pneumatic plug-in valve (3).

7. The solid propellant mechanical properties testing device compatible with SEM and CT according to claim 1 or 2, characterized in that: A suction cup is installed at the end of the robotic arm (6), and the suction cup is connected to the vacuum transfer cabin (1) using the vacuum negative pressure principle.

8. A solid propellant mechanical properties testing method compatible with SEM and CT, characterized in that: The following steps are involved: S1: The robotic arm (6) transfers the vacuum transfer cabin (1) to the docking position of the transfer channel (2), opens the transfer cabin door (101) and the vacuum pneumatic plug valve (3), connects the vacuum transfer cabin (1) with the scanning electron microscope (4), and draws the vacuum degree of the scanning electron microscope (4), the transfer channel (2) and the vacuum transfer cabin (1) to a preset vacuum degree and maintains it; S2: Determine the loading mode of the mechanical property test of the propellant sample. If it is an in-situ tensile test, set the active frameless torque motor (703) and the slave torque motor (712) to a master-slave follower mode; if it is a tensile-torsion test, control the active frameless torque motor (703) and the slave torque motor (712) to operate independently; S3: Turn on the electron gun of the scanning electron microscope (4) and locate the test target area of ​​the propellant sample (709); S4: Setting the loading parameters for the mechanical properties test, the in-situ mechanical testing device (7) completes the target parameter loading and keeps the load from being unloaded; S5: Determine whether it is a SEM / EDS / DIC test. If so, the active frameless torque motor (703) and the driven torque motor (712) rotate the two sets of rotatable fixtures synchronously and in the same direction to a first deflection state. If not, continue to determine whether it is an EBSD test. If so, the active frameless torque motor (703) and the driven torque motor (712) adjust the two sets of rotatable fixtures to a second deflection state. After the imaging angle is adjusted, the scanning electron microscope (4) obtains microscopic morphology information of the surface of the test target area. S6: Determine whether the mechanical property test in the scanning electron microscope (4) is completed. If so, transfer the in-situ mechanical test device (7) to the vacuum transfer chamber (1) through the transfer channel (2), and transport the propellant sample (709) to the bottom of the high-transmittance scanning window (106) through the mobile platform inside the vacuum transfer chamber (1). Close the transfer chamber door (101) and the vacuum pneumatic plug valve (3) in sequence, release the vacuum of the low vacuum section transfer channel (202), and then the robot arm (6) transports the vacuum transfer chamber (1) to the scanning turntable (52) in the dual-source dual-detection industrial CT (5); S7: Synchronously controlling the scanning frequency of the radiation source (53) in the dual-source dual-detection industrial CT (5) and the rotation speed of the two sets of rotatable fixtures in the in-situ mechanical testing device (7), wherein the X-rays emitted by the radiation source (53) penetrate the high-transmittance scanning window (106) and the propellant sample (709) and then irradiate the CT detector (51), thereby obtaining the internal three-dimensional structural information of the propellant sample (709) during the rotation scanning process; S8: After the dual-source dual-detection industrial CT (5) scans and images, it is determined whether the mechanical property test in the dual-source dual-detection industrial CT (5) is completed. If so, the robotic arm (6) transfers the vacuum transfer cabin (1) to dock with the transfer channel on the scanning electron microscope (4), opens the transfer cabin door (101) and the vacuum pneumatic plug valve (3), establishes a vacuum channel between the vacuum transfer cabin (1), the transfer channel (2) and the scanning electron microscope (4), and transports the in-situ mechanical testing device (7) through the transfer channel (2) to the scanning electron microscope (4); S9: Determine whether the combined mechanical property test in the scanning electron microscope (4) and the dual-source dual-detection industrial CT (5) is completed. If so, release the vacuum of the scanning electron microscope (4) and replace the propellant sample (709); if not, return to step S3 until the combined mechanical property test is completed.

9. The solid propellant mechanical properties testing method compatible with SEM and CT according to claim 8, characterized in that: After step S6 and before step S7, the method further includes the following steps: If further mechanical property test information of the propellant sample (709) needs to be obtained, the propellant sample (709) is further loaded and then the process returns to step S4 until the mechanical property test in the scanning electron microscope (4) is completed.

10. The solid propellant mechanical properties testing method compatible with SEM and CT according to claim 8 or 9, characterized in that: The preset vacuum degree range is 0.025Pa~0.055Pa, the first deflection angle state is 0° deflection angle state, and the second deflection angle state is 70° deflection angle state.

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