Triaxial compression test device based on photoelastic instrument

Abstract

The triaxial compression test device based on the photoelastic instrument comprises a light source and an imaging device, a photoelastic instrument main body is arranged between the light source and the imaging device, and the photoelastic instrument main body comprises a front polarization frame and a rear polarization frame which are respectively provided with a front polarizer and a rear polarizer; a test piece loading frame is arranged between the front polarization frame and the rear polarization frame, a downward pressing force application plate is arranged in the test piece loading frame, and a tension sensor is arranged below the downward pressing force application plate. The change of internal stress and a contact force chain of the particles is analyzed by observing the optical performance of the particles, a stress field of the particles is drawn, the rotation angle and the displacement field of the particles can be researched, the micro-mechanical characteristics in the particles are further analyzed, and macro-mechanical information and the micro-mechanical characteristics are combined for analysis; and the property change of the particles in the test process can be better studied.

Description

Technical Field

[0001] The utility model relates to the technical field of shear testing, in particular to a triaxial compression testing device based on a photoelasticity instrument. Background Art

[0002] Photoelasticity is an optical stress measurement method that can measure the stress of transparent material components with relatively complex geometric shapes and loading conditions. In particular, it can measure stress concentration and internal stress problems that are difficult to solve with other methods. Therefore, it has attracted attention from the academic and engineering communities. Photoelasticity has become an effective tool for solving stress analysis problems in complex engineering structures.

[0003] Currently, triaxial compression testing is a traditional technique for measuring the shear strength parameters of rocks and soils. Traditional triaxial compression testing equipment is primarily used to study macroscopic mechanical properties such as soil shear strength. However, it is difficult to directly observe microscopic information, such as the stress field within particles and changes in contact force chains. This has become a significant constraint on further research into the microscopic properties within particles, and as a result, it is impossible to directly combine macroscopic and microscopic mechanical characteristics for analysis.

[0004] Currently, no effective solutions have been proposed for the problems in related technologies. Utility Model Content

[0005] In view of the deficiencies in the prior art, the present invention aims to provide a triaxial compression test device based on a photoelasticity instrument.

[0006] In order to achieve the above-mentioned purpose, the present invention is implemented through the following technical scheme: a triaxial compression testing device based on a photoelasticity instrument, including a light source and an imaging device, a photoelasticity instrument body is arranged between the light source and the imaging device, the photoelasticity instrument body includes a front polarization frame and a rear polarization frame respectively equipped with a front polarizer and a rear polarizer, a specimen loading frame is installed between the front polarization frame and the rear polarization frame, a downward pressure plate is arranged in the specimen loading frame, a tension sensor is arranged below the downward pressure plate, a spiral force device acting on the downward pressure plate is provided on the outer top of the specimen loading frame, a three-axis device is arranged between the downward pressure plate and the tension sensor, and the tension sensor is electrically connected to a digital display instrument.

[0007] Preferably, the three-axis device consists of an air bag assembly, an upper pressure plate, a lower pressure plate and an air pressure controller, the upper pressure plate is connected to the lower pressure plate, the air bag assembly is connected to the upper pressure plate, the lower pressure plate is connected to the air bag assembly, the air pressure controller is installed on the air pump, and the air pump is connected to the air bag assembly through a delivery pipe.

[0008] Preferably, the air bag assembly consists of an air bag pressure plate, a test box, an air bag and a screw, the air bag pressure plate is connected to the upper pressure plate, the test box consists of an upper box and a lower box, the upper box and the lower box are sealed and clamped together, transparent air bag rubber membranes are provided on the outer edges of both ends of the test box, the two ends of the transparent air bag rubber membrane are flipped and fixed on the test box, the grooves on the transparent air bag rubber membrane are nested on the outer edges of the test box, the parts of the transparent air bag rubber membrane fixed to the outer edges of both ends of the test box are fixed by the air bag pressure plate, the test box and the air bag pressure plate are fixed by the screw, an air inlet is provided on the surface of the test box, the air bag is formed between the transparent air bag rubber membrane and the test box, and the conveying pipe is connected to the air bag through the air inlet.

[0009] Preferably, the airbag pressure plate consists of an airbag outer end pressure plate and an airbag inner end pressure plate, the airbag inner end pressure plate is fixed on the inner side of the transparent airbag rubber film, and the airbag outer end pressure plate is fixed on the outer side of the transparent airbag rubber film.

[0010] Preferably, the transparent air bag rubber film is a hollow cube, the diameter of the hollow cube formed by the transparent air bag rubber film is equal to or greater than the diameter of the hollow cube specimen, and the transparent air bag rubber film is placed inside the test box.

[0011] Preferably, a fastening bracket is provided between the front polarization frame and the rear polarization frame, and the front polarization frame, the rear polarization frame and the specimen loading frame are fastened together via the fastening bracket.

[0012] Preferably, the light source is a liquid crystal computer display, and the imaging device is a digital camera, wherein the liquid crystal computer display is connected to a computer host, and the output end of the digital camera is connected to a computer processor.

[0013] The axle up and down groove at two ends embeds respectively in two guide rails up and down of being made up of the groove on the attachment piece, and the tooth on the attachment piece is meshed with tooth on upper sprocket wheel, the lower sprocket.

[0014] The utility model provides a triaxial compression test device based on a photoelasticity instrument, which has the following beneficial effects:

[0015] By placing the triaxial device in the specimen loading frame and connecting the triaxial device with the vertical downward pressure plate and the tension sensor, and then filling the triaxial device with transparent material particles used to replace soil particles; turning on the light source and the imaging device, and then starting the photoelasticity instrument body, rotating the vertical spiral force device to apply vertical pressure to the test box through the vertical downward pressure plate, and transmitting the vertical pressure to the digital display instrument through the tension sensor for easy adjustment of its size, and then controlling the air pump through the air pressure controller to input compressed air into the air bag, thereby controlling the confining pressure of the test, and finally, the imaging device transmits the information to the computer. The utility model combines the triaxial compression test with the photoelasticity method, analyzes the changes in the internal stress and contact force chain of the particles by observing the optical properties of the particles, draws its stress field, and can study the rotation angle and displacement field of the particles, further analyze the microscopic mechanical characteristics inside the particles, and combine the macroscopic mechanical information with the microscopic mechanical characteristics for analysis, so as to better study the changes in the properties of the particles during the test. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] 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.

[0017] Figure 1 This is a front view of a triaxial compression testing device based on a photoelasticity instrument according to an embodiment of the present invention;

[0018] Figure 2 1 is a front view of a photoelasticity instrument body in a triaxial compression testing device based on a photoelasticity instrument according to an embodiment of the present invention;

[0019] Figure 3 1 is a schematic structural diagram of a transparent air bag rubber membrane in a triaxial compression test device based on a photoelasticity instrument according to an embodiment of the present invention;

[0020] Figure 4 BB is a cross-sectional view of a triaxial compression test device based on a photoelasticity instrument according to an embodiment of the present invention;

[0021] Figure 5 is a cross-sectional view of an air bag assembly in a triaxial compression testing device based on a photoelasticity instrument according to an embodiment of the present invention;

[0022] Figure 6This is a bottom view of a spiral force applying device in a triaxial compression testing device based on a photoelasticity instrument according to an embodiment of the present invention;

[0023] Figure 7 The figure is a schematic diagram of the internal structure of a spiral force applying device in a triaxial compression testing device based on a photoelasticity instrument according to an embodiment of the present invention.

[0024] In the picture:

[0025] 1. Light source; 2. Imaging device; 3. Photoelasticity instrument body; 4. Front polarizer; 5. Rear polarizer; 6. Front polarizer frame; 7. Rear polarizer frame; 8. Specimen loading frame; 9. Downward pressure plate; 10. Tension sensor; 11. Screw force device; 12. Three-axis device; 13. Airbag assembly; 14. Upper pressure plate; 15. Lower pressure plate; 16. Air pressure controller; 17. Airbag pressure plate; 18. Test box; 19. Airbag; 20. Screw; 21. Upper box; 22. Lower box; 23. Transparent airbag rubber Membrane; 24. Groove; 25. Pressure plate at the outer end of the air bag; 26. Pressure plate at the inner end of the air bag; 27. Air inlet; 28. Digital display instrument; 29. Fastening bracket; 30. Base; 31. Imaging device bracket; 32. Upper shell; 33. Bearing 1; 34. Rotating shaft; 35. Bevel gear 1; 36. Rotating handwheel; 37. Threaded rod; 38. Lower shell; 39. Lower pressure column; 40. Connecting column; 41. Threaded hole; 42. Limit slider; 43. Limit slide groove; 44. Bearing 2; 45. Support rod. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described 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.

[0027] See also Figure 1-7The present invention provides a triaxial compression test device based on a photoelasticity instrument, comprising a light source 1 and an imaging device 2, a photoelasticity instrument body 3 is provided between the light source 1 and the imaging device 2, the photoelasticity instrument body 3 comprises a front polarization frame 6 and a rear polarization frame 7, each of which is respectively equipped with a front polarizer 4 and a rear polarizer 5, a specimen loading frame 8 is installed between the front polarization frame 6 and the rear polarization frame 7, a downward pressure plate 9 is provided in the specimen loading frame 8, and a tension sensor 10 is provided below the downward pressure plate 9. A spiral force-applying device 11 acting on the downward pressure plate 9 is provided on the outer top of the specimen loading frame 8. A three-axis device 12 is provided between the downward pressure plate 9 and the tension sensor 10. The tension sensor 10 is electrically connected to the digital display instrument 28. The three-axis device 12 is placed in the specimen loading frame 8 and connected to the vertical downward pressure plate 9 and the tension sensor 10. Then, the three-axis device 12 is filled with transparent material particles used to replace soil particles. Turn on the light source 1 and the imaging device 2, then start the photoelasticity instrument body 3, rotate the vertical spiral force device 11 to apply vertical pressure to the test box 18 by vertically pressing the force plate 9, and transmit the vertical pressure to the digital display instrument 28 through the tension sensor 10 to facilitate its size adjustment. Then, the air pressure controller 16 controls the air pump to input compressed air into the air bag 19, thereby controlling the confining pressure of the test. Finally, the imaging device transmits the information to the computer and processes it to analyze the changes in its internal stress and contact force chain, so as to more intuitively analyze the microscopic characteristics of the particles.

[0028] In one embodiment, please refer to the appendix of the specification. Figure 1 and Figure 5 As shown, the three-axis device 12 consists of an air bag assembly 13, an upper pressure plate 14, a lower pressure plate 15, and an air pressure controller 16. The upper pressure plate 14 is connected to the lower pressure plate 9, the air bag assembly 13 is connected to the upper pressure plate 14, the lower pressure plate 15 is connected to the air bag assembly 13, and the air pressure controller 16 is controlled and connected to the air bag assembly 13. The air pressure controller 16 is installed on the air pump, and the air pump is connected to the air bag assembly 13 through a delivery pipe. The air pressure controller 16 is connected to the air bag assembly 13 through the air inlet 27, and cooperates with the upper pressure plate 14 and the lower pressure plate 15 connected to the air bag assembly 13, so that the air pressure controller 16 can control the air pressure in the air bag assembly 13.

[0029] In one embodiment, please refer to the appendix of the specification. Figure 5As shown, the air bag assembly 13 consists of an air bag pressure plate 17, a test box 18, an air bag 19 and a screw 20. The air bag pressure plate 17 is connected to the upper pressure plate 14. The test box 18 consists of an upper box 21 and a lower box 22. The upper box 21 and the lower box 22 are sealed and clamped together. Transparent air bag rubber membranes 23 are provided on the outer edges of both ends of the test box 18. The two ends of the transparent air bag rubber membrane 23 are turned and fixed on the test box 18. The grooves 24 on the transparent air bag rubber membrane 23 are nested on the outer edges of the test box 18; the parts of the transparent air bag rubber membrane 23 fixed to the outer edges of both ends of the test box 18 are fixed by the air bag pressure plate 17, and the test box 18 and the air bag pressure plate 17 are fixed by the screw 20. An air inlet 27 is provided on the surface of the test box 18. The air bag 19 is formed between the transparent air bag rubber membrane 23 and the test box 18, and the delivery pipe is connected to the air bag 19 through the air inlet 27.

[0030] In one embodiment, please refer to the appendix of the specification. Figure 1 As shown, light source 1 is a liquid crystal computer display, and imaging device 2 is a digital camera. The liquid crystal computer display is connected to a computer host, and the output of the digital camera is connected to a computer processor. The connection between the liquid crystal computer display and the computer host allows the screen to provide light sources of various colors. The output of the digital camera is connected to the computer processor, which processes the output information and displays it on another display of the computer processor.

[0031] In one embodiment, please refer to the appendix of the specification. Figure 6-7As shown, the spiral force applying device 11 includes an upper shell 32, a bearing 1 33 is embedded in one side wall of the upper shell 32, a rotating shaft 34 is fixedly installed through the inner ring of the bearing 1 33, one end of the rotating shaft 34 located in the upper shell 32 is connected to a bevel gear 1 35, and a rotating hand wheel 36 is installed at the other end of the rotating shaft 34, a bevel gear 2 is meshed on the bevel gear 1 35, and a threaded rod 37 is connected to the bottom center of the bevel gear 2, and a bearing 2 44 is provided on the outer sleeve of the threaded rod 37, and the outer ring of the bearing 2 44 is passed through The support rod 45 is connected to the inner wall of the upper shell 32, and the lower part of the upper shell 32 is integrally connected to the lower shell 38. A lower pressure column 39 is provided in the lower shell 38, which is movable through the specimen loading frame 8 and connected to the lower pressure force plate 9. A connecting column 40 is integrally connected to the lower pressure column 39. A threaded hole 41 that cooperates with the threaded rod 37 is provided at the center of the connecting column 40. A limiting slider 42 is provided on the outer wall of the connecting column 40, and limiting grooves 43 that are connected to the limiting slider 42 are provided on both sides of the inner wall of the upper shell 32. When applying vertical pressure to the test box 18, first turn the rotating handwheel 36 to drive the rotating shaft 34 to rotate, thereby causing the bevel gear 1 35 to drive the bevel gear 2 to rotate, and the rotation of the bevel gear 2 causes the threaded rod 37 to rotate. Since the threaded rod 37 is threadedly connected to the threaded hole 41 at the center of the connecting column 40, and the threaded rod 37 is limited by the bearing 2 44 and the support rod 45, when the threaded rod 37 rotates, the connecting column 40 is lowered, thereby driving the lower pressure column 39 located in the lower shell 38 to descend, so that the lower pressure column 39 drives the lower pressure plate 9 to apply vertical pressure to the test box 18. The set limiting slider 42 cooperates with the limiting slide groove 43, which has a guiding role when the connecting column 40 descends, and can also prevent the threaded rod 37 from disengaging from the threaded hole 41.

[0032] During use, the two ends of the transparent air bag rubber membrane 23 are flipped and fixed on the outer edges of the two ends of the test box 18. The grooves 24 on the transparent air bag rubber membrane 23 are just nested on the outer edges of the test box 18. Then the parts of the transparent air bag rubber membrane 23 fixed on the outer edges of the two ends of the test box 18 are fixed by the air bag pressing plate 17. The test box 18 and the air bag pressing plate 17 are fixed by screws 20, so that the air bag pressing plate 17 presses the transparent air bag rubber membrane 23 tightly against the two ends of the test box 18. The air inlet 27 on the test box 18 is connected to the air bag 19, and compressed air is input into the air bag 19 through the air pressure controller 16 to control the confining pressure of the test.

[0033] In one embodiment, please refer to the appendix of the specification. Figure 7As shown, the airbag pressure plate 17 is composed of an airbag outer pressure plate 25 and an airbag inner pressure plate 26. The airbag inner pressure plate 26 is fixed to the inner side of the transparent airbag rubber membrane 23, and the airbag outer pressure plate 25 is fixed to the outer side of the transparent airbag rubber membrane 23. The cooperation between the airbag outer pressure plate 25 and the airbag inner pressure plate 26 fixes and compresses the inner and outer sides of the transparent airbag rubber membrane 23, ensuring that the transparent airbag rubber membrane 23 does not loosen.

[0034] In one embodiment, please refer to the appendix of the specification. Figure 3-4 As shown, the transparent air bag rubber membrane 23 is a hollow cube. The diameter of the hollow cube formed by the transparent air bag rubber membrane 23 is equal to or greater than the diameter of the hollow cube specimen. The transparent air bag rubber membrane 23 is placed inside the test box 18 .

[0035] In one embodiment, please refer to the appendix of the specification. Figure 1 As shown, a fastening bracket 29 is provided between the front polarizing frame 6 and the rear polarizing frame 7, and the front polarizing frame 6, the rear polarizing frame 7 and the specimen loading frame 8 are fastened together by the fastening bracket 29. The front polarizing frame 6, the rear polarizing frame 7 and the specimen loading frame 8 are connected and fixed together by the fastening bracket 29.

[0036] In actual application, the three-axis device 12 is placed in the specimen loading frame 8, and the three-axis device 12 is connected to the vertical downward pressure plate 9 and the tension sensor 10, and then the three-axis device 12 is filled with transparent material particles used to replace soil particles; the light source 1 and the imaging device 2 are turned on, and then the photoelasticity instrument body 3 is started, and the vertical spiral force device 11 is rotated to apply vertical pressure to the test box 18 through the downward pressure plate 9, and the vertical pressure is transmitted to the digital display instrument 28 through the tension sensor 10, which is convenient for adjusting its size, and then the air pressure control is used. The device 16 controls the air pump to input compressed air into the air bag 19, thereby controlling the confining pressure of the test. Finally, the imaging device transmits the information to the computer. The utility model combines the triaxial compression test with the photoelastic method. By observing the optical properties of the particles, the changes in their internal stress and contact force chain are analyzed, and their stress field is mapped. The rotation angle and displacement field of the particles can also be studied, and the microscopic mechanical characteristics inside the particles can be further analyzed. The macroscopic mechanical information and microscopic mechanical characteristics are combined for analysis to better study the changes in the properties of the particles during the test.

[0037] Although this specification is described according to implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A triaxial compression test device based on a photoelasticity instrument, characterized in that: The invention comprises a light source (1) and an imaging device (2), wherein a photoelasticity instrument body (3) is provided between the light source (1) and the imaging device (2), wherein the photoelasticity instrument body (3) comprises a front polarization frame (6) and a rear polarization frame (7) respectively provided with a front polarization filter (4) and a rear polarization filter (5), wherein a specimen loading frame (8) is provided between the front polarization frame (6) and the rear polarization frame (7), wherein a downward pressure plate (9) is provided in the specimen loading frame (8), wherein a tension sensor (10) is provided below the downward pressure plate (9), wherein a spiral force device (11) acting on the downward pressure plate (9) is provided on the outer top of the specimen loading frame (8), wherein a three-axis device (12) is provided between the downward pressure plate (9) and the tension sensor (10), and wherein the tension sensor (10) is electrically connected to a digital display instrument (28).

2. A triaxial compression test device based on a photoelasticity instrument according to claim 1, characterized in that: The three-axis device (12) is composed of an air bag assembly (13), an upper pressure plate (14), a lower pressure plate (15), an air pressure controller (16) and an air pump, wherein the upper pressure plate (14) is connected to the lower pressure plate (9), the air bag assembly (13) is connected to the upper pressure plate (14), the lower pressure plate (15) is connected to the air bag assembly (13), the air pressure controller (16) is installed on the air pump, and the air pump is connected to the air bag assembly (13) through a delivery pipe.

3. The triaxial compression test device based on photoelasticity instrument according to claim 2, characterized in that: The air bag assembly (13) is composed of an air bag pressure plate (17), a test box (18), an air bag (19) and a screw (20). The air bag pressure plate (17) is connected to the upper pressure plate (14). The test box (18) is composed of an upper box (21) and a lower box (22). The upper box (21) and the lower box (22) are sealed and clamped together. Transparent air bag rubber membranes (23) are provided on the outer edges of both ends of the test box (18). Both ends of the transparent air bag rubber membrane (23) are turned and fixed on the test box (18). The groove (24) is nested on the outer edge of the test box (18), and the transparent air bag rubber membrane (23) is fixed on the outer edges of both ends of the test box (18) through the air bag pressure plate (17). The test box (18) and the air bag pressure plate (17) are fixed by the screw (20). The surface of the test box (18) is provided with an air inlet (27), and the air bag (19) is formed between the transparent air bag rubber membrane (23) and the test box (18). The delivery pipe is connected to the air bag (19) through the air inlet (27).

4. The triaxial compression test device based on photoelasticity instrument according to claim 3, characterized in that: The air bag pressure plate (17) is composed of an air bag outer end pressure plate (25) and an air bag inner end pressure plate (26), wherein the air bag inner end pressure plate (26) is fixed on the inner side of the transparent air bag rubber film (23), and the air bag outer end pressure plate (25) is fixed on the outer side of the transparent air bag rubber film (23).

5. The triaxial compression test device based on photoelasticity instrument according to claim 4, characterized in that: The transparent air bag rubber film (23) is a hollow cube. The diameter of the hollow cube formed by the transparent air bag rubber film (23) is equal to or greater than the diameter of the hollow cube specimen. The transparent air bag rubber film (23) is placed inside the test box (18).

6. The triaxial compression test device based on photoelasticity instrument according to claim 5, characterized in that: A fastening bracket (29) is provided between the front polarization frame (6) and the rear polarization frame (7), and the front polarization frame (6), the rear polarization frame (7) and the specimen loading frame (8) are fastened together via the fastening bracket (29).

7. The triaxial compression test device based on photoelasticity instrument according to claim 6, characterized in that: The light source (1) is a liquid crystal computer display, and the imaging device (2) is a digital camera, wherein the liquid crystal computer display is connected to a computer host, and the output end of the digital camera is connected to a computer processor.

8. The triaxial compression test device based on photoelasticity instrument according to claim 7, characterized in that: The spiral force applying device (11) comprises an upper shell (32), a side wall of the upper shell (32) is embedded with a bearing 1 (33), the inner ring of the bearing 1 (33) is fixedly penetrated with a rotating shaft (34), one end of the rotating shaft (34) located in the upper shell (32) is connected to a bevel gear 1 (35), the other end of the rotating shaft (34) is installed with a rotating hand wheel (36), the bevel gear 1 (35) is meshed with a bevel gear 2, the bottom center of the bevel gear 2 is connected with a threaded rod (37), the outer sleeve of the threaded rod (37) is provided with a bearing 2 (44), the outer ring of the bearing 2 (44) is connected to the bevel gear 2 (44) by a support rod ( 45) is connected to the inner wall of the upper shell (32), and the lower shell (38) is integrally connected to the lower part of the upper shell (32), and a lower pressure column (39) is provided in the lower shell (38) and is movable through the specimen loading frame (8) and connected to the lower pressure force plate (9), and a connecting column (40) is integrally connected to the lower pressure column (39), and a threaded hole (41) matching the threaded rod (37) is provided at the center of the connecting column (40), and a limiting slider (42) is provided on the outer wall of the connecting column (40), and limiting grooves (43) corresponding to the limiting slider (42) are provided on both sides of the inner wall of the upper shell (32).

Images