A device for detecting the compressive strength of engineering concrete
Patent Information
- Application Number
- CN202610695161.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-05-20
- Publication Date
- 2026-06-23
Smart Images
Figure CN122259364A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of concrete compressive strength testing technology, and specifically to a concrete compressive strength testing device for engineering applications. Background Technology
[0002] Concrete compressive strength testing is the most fundamental and crucial aspect of quality control in civil engineering and building materials. Currently, conventional concrete compressive strength testing typically employs a hydraulic universal testing machine or a dedicated pressure testing machine. This machine applies axial pressure to a standard concrete specimen through upper and lower rigid pressure plates until the specimen fails, thereby obtaining the ultimate compressive strength data.
[0003] However, in practical engineering testing applications, due to limitations in mold precision and molding processes, the top surface of cured concrete test blocks often exhibits unevenness or tilting. Existing testing machine indenters are mostly purely rigid planar structures. When these rigid indenters press down on and contact the rough test block, point contact or localized line contact is easily formed, leading to severe eccentric compression and stress concentration. This causes the test block to prematurely collapse under loads far below its true ultimate strength, resulting in severely distorted test data. Therefore, designing a new engineering-grade concrete compressive strength testing device is a technical problem that engineers need to solve. Summary of the Invention
[0004] The purpose of this invention is to provide a concrete compressive strength testing device for engineering applications, so as to solve the problems mentioned in the background art.
[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:
[0006] A concrete compressive strength testing device for engineering applications includes: a main testing structure, comprising a compressive strength testing device body and a mounting frame disposed on one side of the compressive strength testing device body; a hydraulic pressurizing device is fixedly mounted on the top of the mounting frame; a placement base is fixedly mounted on the bottom of the mounting frame; the placement base and the output end of the hydraulic pressurizing device are arranged vertically opposite each other, configured to cooperate in performing a load compressive strength test on the test block; and a leveling mechanism, fixedly assembled to the output end of the hydraulic pressurizing device, configured to level the concrete block placed on the mounting frame when the hydraulic pressurizing device is driven to press down. The top surfaces of the test blocks on the base abut against each other, and the top surfaces of the test blocks are adaptively leveled in a horizontal position. The centering mechanism is slidably connected to the bottom of the mounting frame and is configured to drive and adjust the test blocks supported on the base before the loading test so that the vertical geometric center line of the test blocks is coaxially aligned with the force axis of the hydraulic pressurization device. The protective plate is fixedly installed in the middle of the mounting frame and is set in the area where the base is located. It is configured to physically intercept and safely isolate the fragments that fly out when the test blocks fracture brittlely during the loading compressive strength test.
[0007] Furthermore, the leveling mechanism includes a mounting base fixedly installed at the output end of the hydraulic pressurizing device. The mounting base has a filling cavity configured to seal and contain filling fluid, and a mounting plate is fixedly sealed at the bottom. The mounting plate has several sliding grooves arranged in an array. A plunger is slidably inserted into each sliding groove along the axial direction. A sealing ring fixedly embedded in the inner wall of the top of the sliding groove slides against the outer wall of the plunger to provide high-pressure dynamic sealing for the filling cavity. A return spring is sleeved in the middle of the plunger, configured to drive the plunger to initially extend and reset under non-load conditions. Adaptive structures are installed sequentially at the bottom of the plunger, and a capacitor structure is installed inside the filling cavity.
[0008] Furthermore, the adaptive structure includes a ball joint head fixedly mounted at the bottom of the plunger, and a ball joint seat is universally hinged at the bottom of the ball joint head. A pressure plate is fixedly mounted at the bottom of the ball joint seat, and is configured to make adaptive conformal compression contact with the uneven top surface of the test block through the free deflection of the ball joint structure.
[0009] Furthermore, the pressure plate is constructed as a square plate structure, configured to allow adjacent pressure plates to be seamlessly arrayed and spliced with a high duty cycle.
[0010] Furthermore, the filling liquid is constructed as a magnetorheological fluid with magnetic field response characteristics, which uses silicone oil as the continuous phase base liquid to provide basic fluidity, and carbonyl iron powder with high magnetic permeability as dispersed phase particles uniformly suspended in the continuous phase base liquid.
[0011] Furthermore, the outer peripheral wall of the plunger tip is provided with several spiral grooves at equal intervals along the circumferential direction to increase the contact area between the plunger tip and the filling fluid.
[0012] Furthermore, the capacitor structure includes a substrate disposed at the top of the filling cavity. The substrate is fixedly mounted on the inner top surface of the mounting base, and microelectrodes are correspondingly mounted on the top of each plunger. It is configured to form a displacement sensing circuit by changing the distance between the substrate and the microelectrodes. The mounting base has an outer mounting ring groove, in which an annular magnetic coil for inducing a phase change in the filling liquid is embedded. The outer periphery of the annular magnetic coil is covered with a cover plate fixedly connected to the outside of the mounting base to seal and isolate the excitation assembly from the outer periphery of the mounting base.
[0013] Furthermore, the centering mechanism includes a fixed seat that is slidably connected to the bottom of the mounting frame. The bottom of the fixed seat is fixedly connected to the output end of the lifting device fixed in the mounting frame to obtain lifting power. An annular toothed plate is rotatably connected to the bottom of the fixed seat, and the output end of the drive device installed at one end of the fixed seat meshes with the annular toothed plate for transmission. Several sliding grooves are opened in an annular array at the top of the fixed seat. A sliding frame is slidably connected in each sliding groove. The bottom end of the sliding frame extends into the fixed seat and meshes with the annular toothed plate, and a clamping structure is fixedly installed at its top end.
[0014] Furthermore, the clamping structure includes a side plate fixedly installed on the top of the sliding frame. Several sliding rods are equidistantly slidably passed through the side plate. One end of each sliding rod passes through the side wall of the sliding frame and is fitted with an auxiliary spring. The auxiliary spring is configured to provide an elastic pre-tightening thrust toward the clamping center to the sliding rod. An airbag is fixedly installed on the side wall of the side plate.
[0015] Furthermore, the airbag has several support ribs arranged in an equidistant array on one side surface near the side plate. The support ribs are configured to provide rigid support for the back of the airbag to ensure the stable transmission of clamping thrust. Each support rib has several deformation relief grooves at both ends. The deformation relief grooves are configured to guide the end of the airbag to produce highly elastic yielding and relief deformation when the airbag is attached to the edge of the test block, thereby eliminating local rigid stress concentration.
[0016] The technical solution provided by this invention may include the following beneficial effects:
[0017] In this example, the independent pressure plates distributed in an array in the leveling mechanism, in conjunction with the ball joint head and ball joint seat, can automatically adapt to the micro-concavity or tilt angle of the top surface of the concrete specimen, transforming the rigid point contact or line contact in traditional testing into a fully covered uniform surface contact. This effectively eliminates stress concentration and eccentric compression caused by unevenness of the specimen surface, ensuring that the obtained compressive strength data can truly reflect the intrinsic strength of the material.
[0018] In this example, the universal ball joint design inside the leveling mechanism can absorb and block the lateral bending moment and shear force generated by the tilt of the test block, ensuring that the upper plunger only bears the axial thrust during the pressurization process. This not only avoids the plunger from mechanically getting stuck in the sliding groove, but also completely solves the problem of one-sided wear of the high-pressure sealing ring, ensuring the dynamic sealing performance and operational stability of the mechanism under high pressure.
[0019] In this example, the device integrates a capacitor structure and utilizes the change in the spacing between the substrate and the microelectrode to form a high-frequency sensing circuit. Combined with the transient phase change characteristics of the magnetorheological fluid, it realizes the digital reconstruction of the surface morphology of the test block and real-time monitoring of the stress state. At the same time, the protective plate is designed to address the brittle fracture characteristics of concrete and achieves physical interception of explosive flying fragments.
[0020] In this example, the centering mechanism uses a ring toothed plate and multiple sliding frames to rigidly mesh and drive, achieving high-level synchronous linkage of the clamping components in the radial direction. Compared with traditional manual centering, this physical synchronization mechanism ensures that the vertical geometric center line of the test block is strictly coaxial with the hydraulic pressure axis, effectively preventing mechanical measurement distortion caused by placement deviation, and improving detection efficiency and reliability.
[0021] In this example, the clamping structure, through a two-stage buffer design of auxiliary springs and flexible airbags, combined with support ribs with deformation relief grooves, achieves flexible wrapping of the sidewall of the specimen. This guides the airbags to produce local elastic yielding when they contact the right-angle edge of the specimen, effectively eliminating rigid stress concentration at the edge. This solves the problem of corner chipping that is very likely to occur during the centering process of concrete specimens from a physical perspective, and maintains the geometric integrity of the sample.
[0022] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description
[0023] The invention will now be further described with reference to the accompanying drawings.
[0024] Figure 1 This is a first-view structural schematic diagram of the device of the present invention.
[0025] Figure 2 This is a second-view structural schematic diagram of the device of the present invention.
[0026] Figure 3 This is a partial structural schematic diagram of the device of the present invention;
[0027] Figure 4 This is a schematic diagram of the hydraulic pressurization device and leveling mechanism of the present invention;
[0028] Figure 5 This is a first-view structural diagram of the leveling mechanism of the present invention in the form of an explosion.
[0029] Figure 6 This is a second-view structural schematic diagram of the leveling mechanism of the present invention in the form of an explosion.
[0030] Figure 7 This is a schematic diagram of the mounting plate structure of the present invention;
[0031] Figure 8 for Figure 7 Enlarged schematic diagram of the structure at point A in the middle;
[0032] Figure 9 This is a schematic diagram of the centering mechanism of the present invention.
[0033] In the diagram: 1. Body of the compressive strength testing device; 2. Mounting frame; 3. Hydraulic pressurizing device; 4. Placement base; 5. Leveling mechanism; 6. Centering mechanism; 7. Protective plate; 8. Mounting seat; 9. Filling cavity; 10. Mounting plate; 11. Sliding groove; 12. Plunger; 13. Closing ring; 14. Return spring; 15. Ball joint head; 16. Ball joint seat; 17. Pressure plate; 18. Mounting ring groove; 19. Annular magnetic coil; 20. Cover plate; 21. Base plate; 22. Microelectrode; 23. Fixing seat; 24. Annular toothed plate; 25. Drive device; 26. Slide groove; 27. Sliding frame; 28. Slide rod; 29. Auxiliary spring; 30. Side plate; 31. Airbag; 32. Support rib. Detailed Implementation
[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this invention. Preferred embodiments of the invention will now be described in more detail with reference to the accompanying drawings. Although preferred embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make the invention more thorough and complete, and to fully convey the scope of the invention to those skilled in the art.
[0035] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular forms “a,” “the,” and “the” used in this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.
[0036] It should be understood that although the terms "first," "second," "third," etc., may be used in this invention to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this invention, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.
[0037] The technical solution of the present invention (Embodiment 1) is described in detail below with reference to the accompanying drawings.
[0038] See Figure 1 , Figure 2 , Figure 3 and Figure 4 The concrete compressive strength testing device used in this project specifically includes: a main testing structure, comprising the compressive strength testing device body 1 and a mounting frame 2 located on one side of the compressive strength testing device body 1. A hydraulic pressurizing device 3 is fixedly installed at the top of the mounting frame 2, and a placement base 4 is fixedly installed at the bottom of the inner part of the mounting frame 2. The placement base 4 and the output end of the hydraulic pressurizing device 3 are arranged vertically opposite each other, configured to cooperate in loading and compressive testing the test block; and a leveling mechanism 5, fixedly assembled at the output end of the hydraulic pressurizing device 3, configured to, when the hydraulic pressurizing device 3 is driven to press down, level the concrete compressive strength testing block with the hydraulic pressurizing device 3. The top surface of the test block placed on the base 4 abuts against each other, and the top surface of the test block is adaptively leveled in a horizontal position; the centering mechanism 6 is slidably connected to the bottom end of the mounting frame 2, and is configured to drive and adjust the test block supported on the base 4 before the loading test, so that the vertical geometric center line of the test block is coaxially aligned with the force axis of the hydraulic pressurizing device 3; the protective plate 7 is fixedly installed in the middle of the mounting frame 2 and is set in the area where the base 4 is located, and is configured to physically intercept and safely isolate the fragments that are splashed when the test block fractures brittlely during the loading compressive strength test.
[0039] It should be noted that before the loading test, the position of the concrete test block placed on the placement base 4 is adjusted by the centering mechanism 6, which is slidably connected to the bottom of the mounting frame 2, so that the vertical geometric center line of the test block is precisely aligned with the force axis of the hydraulic pressurizing device 3, thus eliminating the initial deviation in physical space. Subsequently, the hydraulic pressurizing device 3 is activated to drive the output end to press down. When the leveling mechanism 5 contacts the top surface of the test block, the leveling mechanism 5 can adaptively adjust according to the micro-unevenness or tilt posture of the test block surface to ensure that the pressing surface of the leveling mechanism 5 is in full contact with the surface of the test block, thereby converting the concentrated point load into a uniformly distributed load. With the hydraulic pressurizing device 3 and the placement base 4 working together in a vertical alignment, pressure is continuously applied to the test block for compressive strength testing. During the process of the test block being compressed until it breaks, the protective plate 7 installed in the middle of the mounting frame 2 is in a protective state in real time. When the test block undergoes brittle fracture, the protective plate 7 will physically intercept the generated high-energy flying fragments, ensuring the sealing and safety of the testing process.
[0040] See Figure 5 , Figure 6 , Figure 7 and Figure 8Specifically, the leveling mechanism 5 includes a mounting base 8 fixedly installed at the output end of the hydraulic pressurizing device 3. The mounting base 8 has a filling cavity 9 configured to seal and contain filling fluid, and a mounting plate 10 is fixedly sealed at the bottom. The mounting plate 10 has several sliding grooves 11 arranged in an array. A plunger 12 is slidably inserted into each sliding groove 11 along the axial direction. A sealing ring 13 fixedly embedded in the inner wall of the top of the sliding groove 11 slides against the outer wall of the plunger 12 to perform high-pressure dynamic sealing of the filling cavity 9. A return spring 14 is sleeved in the middle of the plunger 12, configured to drive the plunger 12 to initially extend and reset under non-load conditions. An adaptation structure is installed in sequence at the bottom of the plunger 12. A capacitor structure is installed inside the filling cavity 9.
[0041] It should be noted that: in the initial unloaded state, the array of plungers 12 are in the initial downward extension position under the thrust of the return spring 14. When the hydraulic pressurizing device 3 drives the mounting base 8 to load downward, the bottom array pressure plate 17 first contacts the surface of the concrete test block. Due to the micro-unevenness and inclination of the test block surface, the adaptive structure can undergo adaptive changes to fit the local micro-inclination of the test block. As the pressurization continues, the adaptive structure pushes the corresponding plunger 12 to overcome the spring force and move upward along the sliding groove 11, squeezing the filling liquid inside the filling cavity 9. Subsequently, the capacitor structure is activated to solidify the filling liquid inside the filling cavity 9, so that the position of each plunger 12 is fixed, thereby forcing all pressure plates 17 to tightly wrap and compact the surface of the test block with equal compressive stress, thus better performing compressive strength testing.
[0042] By combining the array of independent pressure plates 17 with the universal ball joint structure, the rigid hard collision of the traditional pressure head on the surface of the test block is transformed into hundreds of flexible surface contacts, ensuring the uniformity of the loading stress and preventing the test block from prematurely breaking due to local stress distortion. This greatly improves the authenticity of the compressive strength data. Secondly, the universal ball joint can prevent the "lateral bending moment shear force" generated by the inclined surface of the test block from being transmitted upward, ensuring that the plunger 12 only bears pure axial thrust. This not only prevents the plunger 12 from getting stuck in the sliding groove 11, but also prevents the high-pressure sealing ring 13 from unilateral wear. This allows the leveling mechanism 5 to maintain a perfect dynamic sealing life under high pressure. Finally, the built-in return spring 14 enables rapid automatic reset preparation after the test, improving the testing efficiency.
[0043] See Figure 6 and Figure 7 Specifically, the adaptive structure includes a ball joint head 15 fixedly installed at the bottom of the plunger 12, and a ball joint seat 16 is universally hinged at the bottom of the ball joint head 15. A pressure plate 17 is fixedly installed at the bottom of the ball joint seat 16 and is configured to make adaptive conformal extrusion contact with the uneven top surface of the test block through the free deflection of the ball joint structure.
[0044] It should be noted that when the hydraulic pressurizing device 3 drives the leveling mechanism 5 to perform the pressurization test downward, the bottom pressure plate 17 will first contact the top surface of the concrete test block, which may have uneven surface or micro-inclination. At this time, relying on the universal hinge joint formed between the ball joint head 15 fixed at the bottom of the plunger 12 and the ball joint seat 16 below, the pressure plate 17 can generate multi-dimensional free deflection, so that each pressure plate 17 can conform to the actual physical morphology of the local part of the test block and achieve adaptive conformal extrusion and bonding.
[0045] The universal ball joint can effectively absorb and block the upward transmission of the "lateral bending moment shear force" generated by the tilt of the test block surface, thereby ensuring that the upper plunger 12 only bears pure axial thrust during the entire pressurization process. This fundamentally avoids the risk of mechanical jamming of the plunger 12 due to lateral compression inside the sliding groove 11, and also avoids the phenomenon of unilateral wear of the high-pressure sealing ring 13. Thus, it ensures that the leveling mechanism 5 can still maintain perfect dynamic sealing life and operational stability when facing extreme high-pressure test environments.
[0046] See Figure 5 Specifically, the pressure plate 17 is constructed as a square plate structure and is configured to allow adjacent pressure plates 17 to be seamlessly arrayed and spliced with a high duty cycle.
[0047] It should be noted that in the mechanical array transmission, the straight boundary structure of the square allows the adjacent pressure plates 17 to achieve extreme edge fit on the two-dimensional plane, thereby splicing together a continuous conformal bearing surface with minimal physical gap. When the leveling mechanism 5 presses down and adaptively fits the rough concrete test block, the pressure plate 17 can fully cover the surface of the test block. During the mechanical transmission process, this high-density seamless splicing surface can instantly disperse and integrate the discrete, point-like thrust load transmitted from each independent plunger 12 above into a uniform and continuous macroscopic surface load on the contact surface, thereby achieving mechanical reconstruction of the uneven surface.
[0048] The square-shaped pressure plate 17 eliminates the geometric gaps and "stress blind spots" that inevitably exist when using circular or other non-closely paved pressure plates 17, maximizing the effective physical contact area between the pressure plate 17 and the concrete specimen. Secondly, when the specimen is subjected to compressive stress, the seamless splicing surface with a high duty cycle can effectively prevent the sand and gravel aggregate on the surface of the concrete from being squeezed into the gaps of the pressure plate 17 under high pressure, thus preventing local micro-shear damage caused by "squeezing and peeling" phenomenon. This ensures that the end face of the specimen is completely under ideal pure axial uniform compression, thereby fundamentally eliminating the interference of the gaps in the pressure plate 17 on the ultimate compressive strength test data.
[0049] See Figure 5Specifically, the filling fluid is constructed as a magnetorheological fluid with magnetic field response characteristics. It uses silicone oil as the continuous phase base fluid to provide basic fluidity, and carbonyl iron powder with high magnetic permeability is uniformly suspended in the continuous phase base fluid as dispersed phase particles.
[0050] It should be noted that the working principle of this filling fluid is based on the unique magnetostrictive transient phase transition characteristics of magnetorheological fluid (MRF). During the initial alignment and leveling stages, before the application of an external magnetic field, the silicone oil, as a continuous phase base fluid, provides excellent basic fluidity and lubricity. The internally suspended carbonyl iron powder particles are in a disordered, free state. At this time, the filling fluid exhibits extremely soft Newtonian fluid characteristics with low shear yield stress, allowing the bottom array plunger 12 to float freely and smoothly up and down under pressure to conform to the sample surface. Once leveling is complete and preparation is underway... When a destructive high voltage is applied, the capacitor structure is instantly activated and magnetized. The carbonyl iron powder particles with high magnetic permeability are rapidly magnetized under the penetration of the strong magnetic field. Within a few milliseconds, they are regularly arranged along the direction of the magnetic field lines and aggregate into a hard chain-like or columnar solid microstructure. This sudden change in the microscopic physical arrangement causes the originally flowing liquid to undergo rheological hardening and phase transformation into a solid-like substance with extremely high compressive strength. This better restricts the position of the plunger 12, thereby cooperating with the hydraulic pressurization device 3 to apply downward pressure to the test block, and thus stably carry out the compressive strength test.
[0051] Utilizing the basic fluidity of silicone oil, it ensures that in the initial stage of contacting uneven test blocks, the pressure plate 17 can achieve zero-resistance pure hydraulic multi-point flexible leveling, completely avoiding stress distortion caused by hard collisions; secondly, after the magnetization phase transformation into a near-solid state, the dense magnetic chain composed of carbonyl iron powder provides extremely strong mechanical stiffness, which can firmly hold the back of all plungers 12 like a cast iron block, so that it will never undergo volume compression or force retreat when subjected to downward pressure, increasing the stability and strength of the device during operation.
[0052] See Figure 7 Specifically, the outer peripheral wall of the top of the plunger 12 is provided with several spiral grooves at equal intervals along the circumferential direction to increase the contact area between the top of the plunger 12 and the filling liquid.
[0053] It should be noted that the spiral groove structure at the top of the plunger 12 can be used during the dynamic conformal stage of the contact test block when the leveling mechanism 5 presses down. When the plunger 12 overcomes the spring force and undergoes axial micro-slippage, the filling liquid in the cavity, i.e., the magnetorheological fluid, will be guided into these spiral grooves to form a spiral fluid channel, thereby multiplying the actual contact surface area between the metal body of the plunger 12 and the filling liquid. When the leveling is completed and the magnetic field applied by the capacitor structure triggers the phase transformation hardening of the filling liquid, the solid-like magnetic chain formed by carbonyl iron powder will tightly fill and anchor inside these spiral grooves, forming a "threaded mechanical engagement" effect between the outer peripheral wall of the plunger 12 and the solidified fluid, like a nut and bolt. This transforms the original single cylindrical friction resistance into a multi-dimensional solid-liquid interface shear resistance, further increasing the smoothness and stability of the device during operation.
[0054] First, during the pressure test phase, the increased contact area and thread engagement effect greatly amplify the axial gripping and locking force of the solidified fluid on the plunger 12, avoiding the risk of microscopic slippage of the plunger 12 under high pressure and ensuring the absolute reliability of the rigid support of the plane. Second, during the dynamic slippage process, when the test block fractures brittlely and the pressure head rebounds instantaneously due to loss of load, the turbulent motion of the fluid in the spiral grooves can generate extremely strong viscous damping, absorbing high-frequency shock waves like a hydraulic shock absorber. This not only achieves in-situ self-damping buffering of the plunger 12, but also significantly reduces the pressure burden on the top sealing ring 13 by gradually consuming fluid pressure, thus extending the fatigue life of the core seal.
[0055] See Figure 6 Specifically, the capacitor structure includes a substrate 21 disposed at the top of the filling cavity 9. The substrate 21 is fixedly mounted on the inner top surface of the mounting base 8, and microelectrodes 22 are correspondingly mounted on the top of each plunger 12. It is configured to form a displacement sensing circuit by changing the distance between the substrate 21 and the microelectrodes 22. The mounting base 8 has a mounting ring groove 18 on its outside, which is embedded with an annular magnetic coil 19 for inducing a phase change in the filling liquid. The outer periphery of the annular magnetic coil 19 is covered with a cover plate 20 fixedly connected to the outside of the mounting base 8 to seal and isolate the excitation assembly from the outer periphery of the mounting base 8.
[0056] It should be noted that during the dynamic process of the leveling mechanism 5 pressing down and adaptively fitting the surface of the test block, each plunger 12 undergoes axial displacement to varying degrees due to the undulations of the test block surface. This causes the microelectrode 22 fixed at its top to move up and down synchronously, thereby continuously changing the physical distance between it and the top insulated and fixed substrate 21. The change in micro-distance is converted into fluctuations in the array capacitance value in real time, forming a high-frequency, high-precision closed-loop displacement sensing circuit. This circuit is used to accurately reconstruct the three-dimensional morphology of the test block surface and monitor changes in micro-stress. At the same time, when the system determines that the flexible leveling action is completed, the annular magnetic coil 19 embedded in the external mounting groove 18 receives the control command and is energized. The powerful closed magnetic lines of force instantly penetrate the non-magnetic inner wall of the mounting base 8 and directly act on the magnetorheological fluid inside the filling cavity 9, inducing the directional chaining of iron powder particles inside and causing a solidification phase change. The outermost cover plate 20 provides protection throughout the process, further improving the smoothness and stability of the device during operation.
[0057] During the adaptive conformal leveling stage before loading and testing, the device enters mode 1. At this time, the filling fluid (magnetorheological fluid) is in a fluid state under zero magnetic field, and each plunger 12 floats freely according to the top surface morphology of the test block. The logic operation control module obtains the capacitance value in real time through each channel. The transient downward displacement of each plunger 12 is calculated based on the physical mapping formula of the parallel plate capacitor. :
[0058]
[0059] Where H is the initial electrode spacing of plunger 12 in the reset state. The vacuum permittivity, Where is the relative permittivity of the medium, and S is the effective sensing area of the microelectrode 22;
[0060] Once leveling is complete and the annular magnetic coil 19 is energized and locked, the system switches to mode 2.
[0061]
[0062] During the testing phase, the magnetic field strength B is kept constant and locked. , Represents the change in impedance; it is the local, real-time dynamic impedance during the test. The initial reference impedance when the circuit is energized and locked but before any load is applied. The difference between , The magnetoresistance sensitivity coefficient represents the magnetorheological fluid. It is a constant determined by the material's physical properties and indicates the sensitivity of the material's impedance to changes in the intensity of an external magnetic field. This represents the change in local magnetic flux density. During the actual testing phase of the device (locked-load phase), since the magnetic field strength of the toroidal magnetic coil is typically constant and locked, the change in magnetic field strength is zero. This also means that the latter part of the formula can usually be canceled out in actual calculations, resulting in further simplification. Therefore, the formula simplifies to:
[0063]
[0064] It is the initial reference impedance when the circuit is just powered on and locked, before any destructive load is applied;
[0065] It is the real-time dynamic impedance during the loading process;
[0066] It is the magnetopiezoresistive sensitivity coefficient of the magnetorheological fluid in this formulation (as specified by the manufacturer).
[0067] It is the actual stress experienced by that local area.
[0068] It should also be noted that the capacitor structure can digitally reconstruct the data changes in the circuit and monitor the stress state in real time, further increasing the stability and smoothness of the device when conducting compressive strength tests.
[0069] See Figure 9 Specifically, the centering mechanism 6 includes a fixed seat 23 slidably connected to the bottom of the mounting frame 2. The bottom of the fixed seat 23 is fixedly connected to the output end of the lifting device fixed in the mounting frame 2 to obtain lifting power. The bottom of the fixed seat 23 is rotatably connected to an annular toothed plate 24, and the output end of the driving device 25 installed at one end of the fixed seat 23 meshes with the annular toothed plate 24 for transmission. The top of the fixed seat 23 is provided with a plurality of sliding grooves 26 in an annular array. Each sliding groove 26 is slidably connected to a sliding frame 27. The bottom end of the sliding frame 27 extends into the fixed seat 23 and meshes with the annular toothed plate 24, and its top end is fixedly installed with a clamping structure.
[0070] It should be noted that during the preparation before the test, the lifting device inside the mounting frame 2 first provides upward power to drive the entire fixed base 23 and the components above it to the working height. Then, the drive device 25 is started, which drives the annular toothed plate 24 located inside the fixed base 23 to rotate. Since the circumferential movement of the sliding frame 27 is restricted by the annular groove 26 at the top of the fixed base 23, when the annular toothed plate 24 rotates, its gear teeth will forcefully push the bottom of the sliding frame 27 that extends to the internal meshing, thereby instantly converting the unidirectional rotational movement of the annular toothed plate 24 into the radial linear movement of multiple sliding frames 27 synchronously contracting towards the center along the groove 26. As the sliding frames 27 synchronously approach each other, the clamping structure fixed at the top will simultaneously abut against the side wall of the concrete test block from all sides. Using equal mechanical thrust in all directions, the test block is smoothly pushed until its geometric center is aligned with the force axis of the hydraulic pressurizing device 3.
[0071] By utilizing a single drive device 25 in conjunction with the rigid transmission of the ring toothed plate 24, the displacement and speed of the clamping components are completely consistent during the retraction process. This avoids the cumulative error of eccentricity that is easily generated when manually centering or when multiple cylinders push independently, ensuring that the test block is in the absolute geometric center position under extreme pressure, thereby obtaining the most accurate compressive strength data. Secondly, the lifting device allows the centering mechanism 6 to sink and avoid collisions when the test block is placed and subjected to load failure. This not only avoids spatial interference with the upper leveling mechanism 5, but also effectively prevents high-energy fragments from damaging the precision gear transmission components at the moment the test block bursts. This significantly improves the service life and maintenance-free cycle of the mechanism in harsh dusty environments.
[0072] It should also be noted that the lifting device is an existing and mature material lifting structure.
[0073] See Figure 9 Specifically, the clamping structure includes a side plate 30 fixedly installed on the top of the sliding frame 27. A plurality of sliding rods 28 are equidistantly slidably passed through the side plate 30. One end of each sliding rod 28 extends out of the side wall of the sliding frame 27 and is sleeved with an auxiliary spring 29. The auxiliary spring 29 is configured to provide an elastic pre-tightening thrust to the sliding rod 28 toward the clamping center. An airbag 31 is fixedly installed on the side wall of the side plate 30.
[0074] It should be noted that during the process of the central mechanism 6 driving the sliding frame 27 to retract inward, the airbag 31 fixed on the side plate 30 first contacts the side wall of the concrete test block. As the clamping force increases, several sliding rods 28 abutting against the back of the airbag 31 are pressed and slide outward on the side plate 30, thereby compressing the auxiliary spring 29 sleeved at its end. At this time, the elastic pre-tightening thrust generated by the auxiliary spring 29 is evenly applied to different parts of the airbag 31 through the sliding rods 28, so that the surface of the flexible airbag 31 can undergo local deformation and micro-conformity according to the roughness of the side wall of the test block, converting the discrete mechanical thrust into a uniformly distributed elastic compressive stress, ensuring that the clamping surface always maintains a stable and gentle flexible contact with the side wall of the test block throughout the entire process of the test block being pushed to the center position.
[0075] By employing a two-stage buffer design with auxiliary spring 29 and airbag 31, the traditional rigid mechanical clamping is transformed into a combination of spring unloading and conformal airbag 31. This effectively avoids local stress concentration caused by unevenness on the side of the test block, and prevents the "corner chipping" damage that is prone to occur at the brittle edges of the concrete test block, thus ensuring the geometric integrity of the test sample. Secondly, the multiple sliding rods 28 distributed in an equidistant array can independently compensate for displacement according to the undulations of the test block surface. This adaptive capability enables the device to stably clamp test blocks with extremely rough surfaces or manufacturing deviations, which not only improves the success rate of automated centering but also further ensures the objectivity and accuracy of the compressive strength test data by reducing mechanical damage to the sidewalls of the test block.
[0076] See Figure 9 Specifically, the airbag 31 has a plurality of support ribs 32 arranged in an equidistant array on one side surface near the side plate 30. The support ribs 32 are configured to provide rigid support for the back of the airbag 31 to ensure stable transmission of clamping thrust. Each of the support ribs 32 has a plurality of deformation relief grooves at both ends. The deformation relief grooves are configured to guide the end of the airbag 31 to produce highly elastic yielding and relief deformation when the airbag 31 is attached to the edge of the test block, thereby eliminating local rigid stress concentration.
[0077] It should be noted that when the centering mechanism 6 performs the clamping action, the equidistant array of support ribs 32 serves as the skeleton of the back of the airbag 31, providing necessary rigidity support when the airbag 31 is compressed, ensuring that the clamping thrust from the side plate 30 can be stably and evenly transmitted to the side of the test block, and preventing the airbag 31 from deforming randomly under heavy pressure. When the airbag 31 contacts and adheres to the right-angle edge of the test block, the deformation clearance grooves at both ends of the support ribs 32 play a guiding role, so that the end of the airbag 31 produces a highly elastic yielding and avoidance deformation when it touches the edge of the test block, thereby conforming to the micro-contour of the test block for flexible wrapping.
[0078] First, the supporting ribs 32 enhance the basic structural rigidity of the back of the airbag 31, ensuring the stable transmission of clamping thrust in complex contact environments, making the centering process of the test block smoother and more precise. Second, the design of the deformation clearance groove cleverly solves the contradiction between rigid thrust and fragile edges. By guiding local yield deformation, it effectively eliminates rigid stress concentration at the edge of the test block, prevents the common "corner chipping" phenomenon of concrete test blocks, and ensures that the test block maintains perfect geometric integrity before entering the formal compressive strength test, thereby improving the scientificity and accuracy of the strength test data.
[0079] The present invention has been described in detail above with reference to the accompanying drawings. In the above embodiments, the descriptions of each embodiment have their own emphasis; for parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments. Those skilled in the art should also understand that the actions and modules involved in the specification are not necessarily essential to the present invention. Furthermore, it is understood that the steps in the method of the embodiments of the present invention can be adjusted, combined, and deleted according to actual needs, and the structure in the device of the embodiments of the present invention can be combined, divided, and deleted according to actual needs.
[0080] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.
Claims
1. A device for testing the compressive strength of concrete used in engineering, characterized in that, include: The main structure of the test includes a compressive strength testing device body (1) and a mounting frame (2) set on one side of the compressive strength testing device body (1). A hydraulic pressurizing device (3) is fixedly installed on the top of the mounting frame (2). A placement base (4) is fixedly provided at the bottom of the inner side of the mounting frame (2). The placement base (4) and the output end of the hydraulic pressurizing device (3) are arranged vertically opposite each other and configured to cooperate in loading and compressive testing of the test block. The leveling mechanism (5) is fixedly mounted on the output end of the hydraulic pressurizing device (3) and is configured to abut against the top surface of the test block placed on the placement base (4) when the hydraulic pressurizing device (3) is driven to press down, and to perform adaptive horizontal posture leveling on the top surface of the test block. The centering mechanism (6) is slidably connected to the bottom end of the mounting frame (2) and is configured to drive and adjust the test block carried on the placement base (4) before the loading test so that the vertical geometric center line of the test block is coaxially aligned with the force application axis of the hydraulic pressurizing device (3). The protective plate (7) is fixedly installed in the middle of the mounting frame (2) and is set in the area where the placement base (4) is located. It is configured to physically intercept and safely isolate the fragments that are splashed when the test block undergoes brittle fracture during the loading and compression test.
2. The engineering concrete compressive strength testing device according to claim 1, characterized in that: The leveling mechanism (5) includes a mounting base (8) fixedly installed at the output end of the hydraulic pressurizing device (3). The mounting base (8) has a filling cavity (9) configured to seal and contain filling liquid, and a mounting plate (10) is fixedly closed at the bottom. The mounting plate (10) has several sliding grooves (11) arranged in an array. Each sliding groove (11) has a plunger (12) slidably inserted into it along the axial direction. The closing ring (13) fixedly embedded in the inner wall of the top of the sliding groove (11) slides against the outer wall of the plunger (12) to perform high-pressure dynamic sealing of the filling cavity (9). A return spring (14) configured to drive the plunger to initially extend and reset in the unloaded state is sleeved in the middle of the plunger (12). An adaptation structure is installed in sequence at the bottom of the plunger (12). A capacitor structure is installed inside the filling cavity (9).
3. The engineering concrete compressive strength testing device according to claim 2, characterized in that: The adaptive structure includes a ball joint head (15) fixedly installed at the bottom of the plunger (12), and a ball joint seat (16) is universally hinged at the bottom of the ball joint head (15). A pressure plate (17) is fixedly installed at the bottom of the ball joint seat (16), which is configured to make adaptive conformal extrusion contact with the uneven top surface of the test block through the free deflection of the ball joint structure.
4. The engineering concrete compressive strength testing device according to claim 3, characterized in that: The pressure plate (17) is constructed as a square plate structure and is configured to allow adjacent pressure plates (17) to be seamlessly arrayed with a high duty cycle.
5. The engineering concrete compressive strength testing device according to claim 4, characterized in that: The filling fluid is constructed as a magnetorheological fluid with magnetic field response characteristics. It uses silicone oil as the continuous phase base fluid to provide basic fluidity, and carbonyl iron powder with high magnetic permeability is uniformly suspended in the continuous phase base fluid as dispersed phase particles.
6. The engineering concrete compressive strength testing device according to claim 5, characterized in that: The top outer peripheral wall of the plunger (12) is provided with several spiral grooves at equal intervals along the circumferential direction to increase the contact area between the top of the plunger (12) and the filling liquid.
7. The engineering concrete compressive strength testing device according to claim 6, characterized in that: The capacitor structure includes a substrate (21) disposed at the top of the filling cavity (9). The substrate (21) is fixedly mounted on the inner top surface of the mounting base (8), and microelectrodes (22) are correspondingly mounted on the top of each plunger (12). It is configured to form a displacement sensing circuit by changing the distance between the substrate (21) and the microelectrodes (22). The mounting base (8) has an outer mounting ring groove (18), which is embedded with an annular magnetic coil (19) for inducing a phase change in the filling liquid. The outer periphery of the annular magnetic coil (19) is covered with a cover plate (20) fixedly connected to the outside of the mounting base (8) to seal and isolate the excitation assembly from the outer periphery of the mounting base (8).
8. The engineering concrete compressive strength testing device according to claim 7, characterized in that: The centering mechanism (6) includes a fixed seat (23) slidably connected to the bottom of the mounting frame (2). The bottom of the fixed seat (23) is fixedly connected to the output end of the lifting device fixed in the mounting frame (2) to obtain lifting power. The bottom of the fixed seat (23) is rotatably connected to an annular toothed plate (24). The output end of the drive device (25) installed at one end of the fixed seat (23) meshes with the annular toothed plate (24) for transmission. The top of the fixed seat (23) is provided with a number of sliding grooves (26) in an annular array. Each sliding groove (26) is slidably connected to a sliding frame (27). The bottom end of the sliding frame (27) extends into the fixed seat (23) and meshes with the annular toothed plate (24). A clamping structure is fixedly installed at its top end.
9. The engineering concrete compressive strength testing device according to claim 8, characterized in that: The clamping structure includes a side plate (30) fixedly installed on the top of the sliding frame (27). A plurality of sliding rods (28) are equidistantly slidably passed through the side plate (30). One end of the sliding rod (28) passes through the side wall of the sliding frame (27) and is sleeved with an auxiliary spring (29). The auxiliary spring (29) is configured to provide an elastic pre-tightening thrust toward the clamping center to the sliding rod (28). An airbag (31) is fixedly installed on the side wall of the side plate (30).
10. The engineering concrete compressive strength testing device according to claim 9, characterized in that: The airbag (31) has a plurality of support ribs (32) arranged in an equidistant array on one side surface near the side plate (30). The support ribs (32) are configured to provide rigid support for the back of the airbag (31) to ensure stable transmission of clamping thrust. Each of the support ribs (32) has a plurality of deformation relief grooves at both ends. The deformation relief grooves are configured to guide the end of the airbag (31) to produce highly elastic yielding and relief deformation when the airbag (31) is attached to the edge of the test block, thereby eliminating local rigid stress concentration.