An experimental device for studying the mechanical properties of horizontal granular systems

Abstract

The present invention discloses an experimental device for studying the mechanical properties of a horizontal granular system, which includes a fixed bottom plate, a measurement part, an electric slide rail part and a baffle; the measurement part includes a support, a platform plate, side plates, a spacing control plate, a movable pressing plate and a force measuring member, and the force measuring member includes a first movable long plate and a second movable long plate which are parallel to each other and a side wall pressure sensor; the electric slide rail part includes a base, a motor, a guide rail, a slider, a micro-displacement device and a force application recording sensor; after the slider moves towards the platform plate side, the force application recording sensor contacts the movable pressing plate and pushes the movable pressing plate to move towards the spacing control plate side, and after the slider moves in the reverse direction, the force application recording sensor disengages from the movable pressing plate. The present invention can perform a ballasting operation on the granular system on the platform plate, and can separate the influence of gravity from the influence of an external load, providing an experimental basis for powder engines and 3D printing technology.

Description

Technical Field

[0001] The present invention belongs to the field of physical experimental devices, and particularly relates to an experimental device for studying the mechanical properties of a horizontal granular system. Background Art

[0002] Granular materials are one of the most familiar substances to people, and the research on their mechanical behavior occupies an important position in engineering and physics. The reason why granular materials attract wide attention is mainly due to their complex internal structure and behavior. In 1884, the British scientist Roberts first observed and reported the phenomenon that the pressure at the bottom of a granary reached saturation when the stacking height exceeded twice its diameter. A few years later, the German engineer Janssen used a continuum model to explain the pressure saturation phenomenon in the granary, believing that the existence of friction caused part of the vertical gravity to transfer to the container wall, thus achieving pressure saturation, and defining the turning ratio as the turning coefficient. The Janssen model is of great significance for granary design and is still widely used today.

[0003] The complex internal structure and behavior of granular materials result in rich and variable macroscopic mechanical properties of granular materials, such as plasticity, brittle failure, viscoelasticity, and granular rheological properties, etc. Due to these properties, when subjected to an external load, the granules will exhibit rich macroscopic behaviors. For example, Wang et al. found that there will be an obvious bimodal distribution at the bottom of the granules under point pressure, and this distribution is closely related to the magnitude of the external force; Vanel et al. found that when there is an external load, the stacked granules will exhibit an overshoot effect. However, at present, most of the research on how external loads affect the mechanical properties of granular systems focuses on the theoretical and simulation parts, and there is little experimental design. Moreover, most of the experimental designs focus on the situation where gravity and external forces act simultaneously, and there is little research on granular systems that are only subjected to external forces. In addition, when studying the influence of external forces using traditional methods, it is all by subtracting the data when gravity acts alone from the data when gravity and external forces act simultaneously. Such an operation is very complex to actually execute, and the result will not be a true and effective result because of the change in the contact force of the granular system.

[0004] Therefore, it is necessary to design a new set of horizontal ballast experimental devices to solve the above problems. Summary of the Invention

[0005] In order to solve the problem that the above experimental devices are mostly used when gravity and external forces act simultaneously and cannot separate the influence of gravity from the influence of external loads, the present invention provides an experimental device for studying the mechanical properties of a horizontal granular system.

[0006] The experimental device for studying the mechanical properties of a horizontal granular system according to the present invention includes a fixed bottom plate, a measuring part installed on the fixed bottom plate, an electric slide rail part installed on the fixed bottom plate and on one side of the measuring part, and a baffle installed on the fixed bottom plate and on the other side of the measuring part;

[0007] The measuring part includes a support, a platform plate, side plates, a spacing control plate, a movable pressing plate, and a force measuring piece. The bottom of the support is installed on the fixed bottom plate. The platform plate is installed on the support and is horizontal. The side plates are installed on the platform plate. The spacing control plate, the movable pressing plate, and the force measuring piece are all placed on the platform plate. The force measuring piece includes a first movable long plate and a second movable long plate that are parallel to each other, and a side wall pressure sensor. The side wall pressure sensor is placed between the two movable long plates and is in contact with the two movable long plates. The side plate is opposite to the first movable long plate, and the two opposite surfaces are parallel. The side of the second movable long plate away from the side wall pressure sensor is in contact with the two supports and is blocked by the supports. The movable pressing plate and the spacing control plate are both located between the side plate and the first movable long plate. The width of the movable pressing plate is slightly smaller than the spacing between the side plate and the first movable long plate. The spacing control plate is strip-shaped, one end is in vertical contact with the side plate, and the other end is in vertical contact with the first movable long plate. A granular placement area is formed by the side plate, the spacing control plate, the first movable long plate, and the movable pressing plate;

[0008] The electric slide rail part includes a base, a motor, a guide rail, a slider, a micro-displacement device, and a force application recording sensor. The base is installed on the fixed bottom plate. The motor and the guide rail are installed on the base. The slider is slidably connected to the guide rail. The micro-displacement device is installed on the slider. The force application recording sensor is installed on the micro-displacement device. The motor controls the sliding of the slider; after the slider moves towards the platform plate side, the force application recording sensor comes into contact with the movable pressing plate and pushes the movable pressing plate to move towards the spacing control plate side. After the slider moves in the reverse direction, the force application recording sensor disengages from the movable pressing plate;

[0009] One side of the baffle is in contact with the edge of the platform plate to block the spacing control plate.

[0010] Further, the support includes four feet and two supporting plates. The feet are L-shaped plates formed by connecting a horizontal plate and a vertical plate. The horizontal plate is installed on the fixed bottom plate. One supporting plate is horizontally installed in the middle of the vertical plates of the two feet on one side, and the other supporting plate is horizontally installed in the middle of the vertical plates of the two feet on the other side. The two sides of the platform plate are respectively installed on the two supporting plates.

[0011] Further, the side of the spacing control plate opposite to the movable pressing plate is a row of comb teeth. The groove between two comb teeth is a semi-circle with a diameter of 5 mm. The distance between the front ends of each comb tooth located between the two grooves on both sides is 0 - 1.76 mm. In this way, each particle is fitted into a groove, and the spacing between adjacent particles can be controlled.

[0012] Further, the force application recording sensor is fixedly connected to the micro-displacement device through a sensor support plate; the side wall pressure sensor contacts the midpoint of the first movable long plate. In this way, the stable and reliable operation of each sensor can be ensured.

[0013] Further, the platform plate is a tempered glass plate. Tempering the glass can prevent deviations in the measurement of the mechanical behavior of particles due to the deformation of the glass during long-term use, making the obtained experimental data more stable and reliable.

[0014] Further, a connecting plate is also connected to the baffle for expanding the connection to external devices. In this way, it is beneficial to connect external devices to achieve more functions (for example, in subsequent experiments, it may be necessary to attach a sensor to the baffle to measure the pressure received at the end of the particle system).

[0015] Advantages: The present invention can perform ballasting operations on the particulate system on the platform plate, separating the influence of gravity from that of the external load; the present invention can endow the experimental content with rich physical connotations and the experimental method is direct, and the structure of the experimental device is scalable, facilitating the study of various properties of the horizontal system; in practice, the present invention has certain guiding significance. At present, horizontal particle transportation is widely used in powder engines and 3D printing technologies, and this experimental device can provide an experimental basis for the technological update of such products; in addition, the device has strong expandability, and the magnitude of the applied force can be precisely controlled by the micro-displacement device and the motor on the slide rail, and it is applicable to a wide range of systems; all components of this experimental device are easy to disassemble. Most of the internal components are connected by screws and nuts instead of welding. For systems of different sizes or different research contents, the device can be conveniently replaced or expanded; the speed of the slider in this experimental device is controlled by the motor, and there is an independent control terminal, which is convenient to operate, and the magnitude of the applied force can be adjusted by using the micro-displacement device to ensure a stable output of the external force; the experimental device of the present invention can directly study the effect of the external force on the two-dimensional particulate system. When studying the influence of the external force by the traditional method, the data obtained by the simultaneous action of the external force and gravity is subtracted from the data of the gravity acting alone. Such an operation is very complicated to actually execute, and the result will not be a true and effective result because of the change in the contact force of the particulate system; in the present invention, the platform plate is designed in the horizontal direction, and the influence of gravity and the external force on the particulate system can be separated during the study, and the influence of the external force on the particulate system can be reflected on the sensor, facilitating the study; the data post-processing of this experimental device is convenient. When conducting the steering coefficient experiment by the traditional method, it is necessary to observe and record the sensor data and then perform data processing. The recording and processing of a large amount of data not only take time and effort, but may also lead to recording errors or data processing errors due to the observer's own reasons. The present invention utilizes the characteristics of the sensor itself, and the data can be saved to the computer by the serial communication method of the program (or a program can be designed to read and process the data) supporting the pressure sensor manufacturer. The saved csv file can be processed and analyzed later, which will greatly improve the convenience of the experiment and facilitate the recording and analysis of data. Brief Description of the Drawings

[0016] Figure 1 It is a schematic structural diagram of the experimental device of the present invention;

[0017] Figure 2 It is a physical photo of the experimental device of the present invention;

[0018] Figure 3 It is a relationship diagram of different packing angles and steering coefficients obtained by using the experimental device of the present invention under an external force of 5N;

[0019] In the figure, 1 is a fixed base plate; 2 is a support leg; 3 is a support plate; 4 is a platform plate; 5 is a side plate; 6 is a movable extrusion plate; 7 is a spacing control plate; 8 is a first movable long plate; 9 is a side wall pressure sensor; 10 is a second movable long plate; 11 is a particle placement area; 14 is a base; 15 is a motor; 16 is a guide rail; 17 is a slider; 18 is a micro-displacement device; 19 is a force application recording sensor; 20 is a sensor support plate; 21 is a horizontal plate; 22 is a vertical plate; 23 is a baffle; 24 is a connecting plate. Detailed implementation mode

[0020] Now, the present invention will be further described in detail through embodiments with reference to the accompanying drawings, but the present invention is not limited to the embodiments.

[0021] As Figure 1 shown, the present invention is an experimental device for studying the mechanical properties of a horizontal granular system, including a fixed base plate 1 (optical platform), a measuring part installed on the fixed base plate 1, an electric slide rail part installed on the fixed base plate 1 and on one side of the measuring part, and a baffle 23 installed on the fixed base plate 1 and on the other side of the measuring part.

[0022] The above-mentioned measuring part includes a support, a platform plate 4, a side plate 5, a spacing control plate 7, a movable extrusion plate 6 and a force measuring member. The above-mentioned support includes four support legs 2 and two support plates 3. The support leg 2 is an L-shaped plate formed by welding a horizontal plate 21 and a vertical plate 22. The horizontal plate 21 is installed on the fixed base plate 1 by screws. One support plate 3 is horizontally installed in the middle of the vertical plates 22 of the two support legs 2 on one side by screws and nuts. The other support plate 3 is also horizontally installed in the middle of the vertical plates 22 of the two support legs 2 on the other side by screws and nuts. The two sides of the platform plate 4 are respectively installed on the two support plates 3 by bolts and nuts and are horizontal. The platform plate 4 can specifically be a tempered glass plate.

[0023] The side plate 5 is mounted on the upper surface of the platform plate 4 by screws and is located on one side of the platform plate 4. The spacing control plate 7, the movable pressing plate 6 and the force measuring member are all placed on the platform plate 4. The force measuring member includes a first movable long plate 8 and a second movable long plate 10 that are parallel to each other and a side wall pressure sensor 9 (AR-8101M, Allison Technology Company). The two movable long plates are both placed flat on the platform plate 4. The side wall pressure sensor 9 is placed between the two movable long plates and contacts the two movable long plates. Among them, the side wall pressure sensor 9 contacts the midpoint of the first movable long plate 8; the side plate 5 is opposite to the first movable long plate 8, and the two opposite surfaces are parallel. The second movable long plate 10 is located on the other side of the platform plate 4 opposite to the side plate 5. The side surface of the second movable long plate 10 away from the side wall pressure sensor 9 contacts and is blocked by the vertical plates of the two feet 2 on this side; the movable pressing plate 6 and the spacing control plate 7 are both located between the side plate 5 and the first movable long plate 8. The width of the movable pressing plate 6 is slightly smaller than the spacing between the side plate 5 and the first movable long plate 8. The spacing control plate 7 is strip-shaped, one end is in vertical contact with the side plate 5, and the other end is in vertical contact with the first movable long plate 8. A particle placement area 11 is formed by the side plate 5, the spacing control plate 7, the first movable long plate 8 and the movable pressing plate 6. On the side of the spacing control plate 7 opposite to the movable pressing plate 6 is a row of comb teeth. The groove between two comb teeth is a semicircle with a diameter of 5 mm. The distance between the front ends of each comb tooth located between the surfaces of the two grooves is 1.76 mm.

[0024] The above-mentioned electric slide rail part includes a base 14, a motor 15, a guide rail 16, a slider 17, a micro-displacement device 18 (LY90-CM (mid-position), Runjia Pneumatic Company), and a force application recording sensor 19 (CX-5816, Dayang Descent Company). The base 14 is mounted on the fixed bottom plate 1 by screws. The motor 15 and the guide rail 16 are mounted on the base 14 by screws. The slider 17 is slidably connected to the guide rail 16. The micro-displacement device 18 is mounted on the slider 17 by screws. The force application recording sensor 19 is mounted on the micro-displacement device 18 through a sensor support plate 20 and using screws. The motor 15 controls the sliding of the slider 17; the above-mentioned sensor support plate 20 is formed by fixing a vertical plate between two parallel plates; after the slider 17 moves towards the platform plate 4 side, the force application recording sensor 19 contacts the movable pressing plate 6 and pushes the movable pressing plate 6 to move towards the spacing control plate 7 side. After the slider 17 moves in the reverse direction, the force application recording sensor 19 disengages from the movable pressing plate 6. The above-mentioned motor 15 and the two sensors both have built-in voltage transformation devices and can be directly connected to a 220V AC power supply.

[0025] The above-mentioned baffle 23 is L-shaped and is fixed to the fixed bottom plate 1 by screws at the bottom. One side surface of the upper side part contacts the edge of the platform plate 4 for blocking the spacing control plate 7. A connecting plate 24 is also connected to the baffle 23 by screws for expanding and connecting external devices. The above-mentioned connection methods using screws, nuts, etc. are all conventional techniques.

[0026] When using this experimental device (as shown in Figure 2 ), to study the steering coefficient under an externally applied force, a computer installed with the Windows system needs to be used in conjunction. Under no-load conditions (when the force application recording sensor 19 is not in contact with the movable pressing plate 6), zero calibration is performed on the pressure data. Then, before the experiment, the bottom-layer particles (stainless steel disks with D = 5 mm, ρ = 7.8 g / cm 3 and a height of 5 mm) are arranged in the particle placement area 11 according to the grooves on the corresponding spacing control plate 7. For example, 22 grooves are selected for an alternating lattice arrangement. Then, during the experiment, the motor 15 of the electric slide rail is turned on to control the movement of the slider 17. The movement of the slider 17 drives the movement of the micro-displacement device 18, and further drives the force application recording sensor 19 to move towards the movable pressing plate 6, and it is ensured that the distance between the force application recording sensor 19 and the movable pressing plate 6 is within the range of the micro-displacement device 18. Then, the knob on the micro-position device is adjusted to make the force application recording sensor 19 slowly move forward to push the movable pressing plate 6, so that the movable pressing plate 6 squeezes the particle system. During this period, the pressure received by the top of the particle system is adjusted according to the reading on the force application recording sensor 19; after the particle system is forced to be squeezed by the first movable long plate 8, the pressure data is measured by the sidewall pressure sensor 9. Finally, the data on the sidewall pressure sensor 9 is recorded and sent to the computer through the Wifi transmitter, and post-processing is performed through the Matlab program in the computer, and the change curve of the steering coefficient with the packing angle under an externally applied force can be obtained, and it is in good agreement with the theoretical value, as shown in Figure 3 . Among them, the abscissa θ represents the packing angle of the particle system, which is obtained from the geometric relationship after selecting different grooves for an alternating lattice in the particle placement area 11; the ordinate k represents the steering coefficient of the particle system, which is obtained by dividing the readings of the sidewall pressure sensor 9 and the force application recording sensor 19; Figure 3 In

[0027] For the technologies not specifically mentioned above, reference is made to the existing technologies.

[0028] Taking the ideal embodiments of the present invention described above as an inspiration, through the above description, relevant staff can completely make various changes and modifications without departing from the technical idea of this invention. The technical scope of this invention is not limited to the content in the specification.

Claims

1. An experimental device for studying the mechanical properties of a horizontal particle system, characterized in that: It comprises a fixed base plate (1), a measuring part mounted on the fixed base plate (1), an electric slide rail part mounted on the fixed base plate (1) and located on one side of the measuring part, and a baffle (23) mounted on the fixed base plate (1) and located on the other side of the measuring part; The measuring part comprises a support, a platform plate (4), a side plate (5), a spacing control plate (7), a movable extrusion plate (6) and a force measuring piece. The bottom of the support is mounted on a fixed bottom plate (1). The platform plate (4) is mounted on the support and is horizontal. The side plate (5) is mounted on the platform plate (4). The spacing control plate (7), the movable extrusion plate (6) and the force measuring piece are all placed on the platform plate (4). The force measuring piece comprises a first movable long strip plate (8) and a second movable long strip plate (10) which are parallel to each other, and a side wall pressure sensor (9). The side wall pressure sensor (9) is placed between the first movable long strip plate (8) and the second movable long strip plate (10) and is in contact with the first movable long strip plate (8) and the second movable long strip plate (10). 5) is opposite to the first movable strip plate (8), and the two opposite surfaces are parallel, a side of the second movable strip plate (10) away from the side wall pressure sensor (9) contacts with two supports and is blocked by the supports, the movable extrusion plate (6) and the spacing control plate (7) are both located between the side plate (5) and the first movable strip plate (8), the width of the movable extrusion plate (6) is slightly smaller than the spacing between the side plate (5) and the first movable strip plate (8), the spacing control plate (7) is in a long strip shape, one end of which is in vertical contact with the side plate (5) and the other end of which is in vertical contact with the first movable strip plate (8), and a particle placement area (11) is surrounded by the side plate (5), the spacing control plate (7), the first movable strip plate (8) and the movable extrusion plate (6); The electric slide rail portion comprises a base (14), a motor (15), a guide rail (16), a slider (17), a micro-displacement device (18), and a force recording sensor (19); the base (14) is mounted on a fixed base plate (1); the motor (15) and the guide rail (16) are mounted on the base (14); the slider (17) is slidably connected to the guide rail (16); the micro-displacement device (18) is mounted on the slider (17); the force recording sensor (19) is mounted on the micro-displacement device (18); and the motor (15) controls the slider (17) to slide; after the slider (17) moves toward the platform plate (4), the force recording sensor (19) contacts the movable extrusion plate (6) and pushes the movable extrusion plate (6) to move toward the spacing control plate (7); and after the slider (17) moves in the opposite direction, the force recording sensor (19) is disconnected from the movable extrusion plate (6); One side of the baffle plate (23) contacts the edge of the platform plate (4) to block the spacing control plate (7).

2. The experimental device for studying the mechanical properties of horizontal particle systems according to claim 1, characterized in that: The support comprises four supporting legs (2) and two supporting plates (3), wherein the supporting legs (2) are L-shaped plates formed by connecting a horizontal plate (21) and a vertical plate (22), wherein the horizontal plate (21) is mounted on a fixed bottom plate (1), one supporting plate (3) is horizontally mounted in the middle of the vertical plates (22) of the two supporting legs (2) on one side, and another supporting plate (3) is horizontally mounted in the middle of the vertical plates (22) of the two supporting legs (2) on the other side, and two side portions of the platform plate (4) are respectively mounted on the two supporting plates (3).

3. The experimental device for studying the mechanical properties of horizontal particle systems according to claim 2, characterized in that: A row of comb teeth is provided on the side of the spacing control plate (7) opposite to the movable extrusion plate (6), the groove between the two comb teeth is a semicircle with a diameter of 5 mm, and the distance between the front end of each comb tooth and the surface of the groove on both sides is 0-1.76 mm.

4. The experimental device for studying the mechanical properties of horizontal particle systems according to claim 3, characterized in that: The force recording sensor (19) is fixedly connected to the micro-displacement device (18) via a sensor support plate (20); and the side wall pressure sensor (9) is in contact with the midpoint of the first movable long strip plate (8).

5. The experimental device for studying the mechanical properties of horizontal particle systems according to claim 4, characterized in that: The platform plate (4) is a tempered glass plate.

6. The experimental device for studying the mechanical properties of horizontal particle systems according to claim 5, characterized in that: The baffle plate (23) is also connected to a connecting plate (24) for expanding the connection with an external device.

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