Air pressure loading structure testing machine

Abstract

An air pressure loading structure testing machine, comprising a reaction frame (1), a loading plate (2), and an expansion assembly (3). The reaction frame (1) comprises a reaction beam (11) and a supporting part (12); the reaction beam (11) is arranged on the supporting part (12); the loading plate (2) is arranged on the supporting part (12) and is arranged opposite to the reaction beam (11) in the direction of extension of the supporting part (12) to form a first cavity (122); the reaction frame (1) and the side of the loading plate (2) facing away from the reaction beam (11) form a second cavity (123); the loading plate (2) can move relative to the reaction frame (1) in the length direction of the reaction frame (1), or the loading plate (2) can rotate relative to the reaction frame (1) in the width direction of the reaction frame (1); the expansion assembly (3) is arranged in at least one of the first cavity (122) and the second cavity (123); the second cavity (123) is suitable for mounting a test piece (103), and the test piece (103) abuts against the loading plate (2); the expansion assembly (3) is suitable for introduction of an expansion medium to adjust the acting force of the loading plate (2) on the test piece (103); and the rigidity and damping of the expansion assembly (3) are both less than the rigidity and damping of the test piece (103). The testing machine can apply a controllable pressure to the test piece (103), has a weak constraint on the vertical displacement of the test piece (103), and produces less damping.

Description

Air pressure loading structural testing machine

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on the Chinese patent application with application number 202310955984.8 and application date of July 31, 2023, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into this application as a reference. Technical Field

[0003] The present disclosure belongs to the technical field of civil engineering structure testing, and in particular relates to a pneumatic loading structure testing machine. Background Art

[0004] The mechanical properties of some structural components are affected by the magnitude of external pressure. For example, the vertical stiffness of rubber bearings usually increases with the increase of vertical pressure. Therefore, when testing the mechanical properties of structural components, the pressure on the specimen should be consistent with the actual usage status in the project.

[0005] In related technologies, testing machines are unable to simulate the actual boundary conditions of structural specimens in engineering applications, resulting in large detection errors.

[0006] Summary of the Invention

[0007] In the relevant technology, for pressure-bearing components such as seismic isolation bearings, the structure above the bearing in actual engineering can be regarded as a mass body that is not constrained by external displacement. The upper structure only provides pressure on the bearing without constraining the vertical deformation of the bearing. Traditional structural testing machines in the field of civil engineering use hydraulic or electromagnetic actuators to apply external force to the specimen to simulate the stress condition of the specimen. However, due to the large stiffness of the actuator, the vertical vibration of the bearing will be constrained during the bearing compression test, which is inconsistent with the situation in actual engineering where the bearing is only under pressure but not vertically constrained by displacement. The damping of electromagnetic and hydraulic actuators is large, which will cause the free vibration of the structural specimen in contact with the actuator to decay rapidly. In addition, the vibration noise generated by the general structural testing machine itself during operation is large, which is not conducive to collecting the vibration signal of the specimen, and the transfer function method cannot be used to measure the dynamic characteristics of the bearing specimen under compression.

[0008] It can be seen that the use of hydraulic loading structural testing machines to measure the dynamic characteristics of structural specimens cannot simulate the actual boundary conditions of structural specimens in engineering applications. Therefore, there is an urgent need for a structural testing machine that can apply controllable pressure to the specimen while limiting the vertical displacement of the specimen as weakly as possible and with as little damping as possible.

[0009] The present disclosure aims to solve one of the technical problems in the related art at least to a certain extent.

[0010] To this end, the embodiments of the present disclosure provide a pneumatic loading structural testing machine with a simple structure, accurate detection, and small error.

[0011] According to an embodiment of the present disclosure, the pneumatic loading structural testing machine includes: a reaction frame, the reaction frame including a reaction beam and a support part, the reaction beam being arranged on the support part; a loading plate, the loading plate being arranged on the support part and being spaced relative to the reaction beam along the extension direction of the support part to form a first cavity, the loading plate forming a second cavity with the reaction frame on a side away from the reaction beam, the loading plate being movable relative to the reaction frame along the length direction of the reaction frame, or the loading plate being rotatable relative to the reaction frame around the width direction of the reaction frame; an expansion assembly, the expansion assembly being arranged in at least one of the first cavity and the second cavity, the second cavity being suitable for installing a specimen and the specimen being against the loading plate, the expansion assembly being suitable for introducing an expansion medium to adjust the force exerted by the loading plate on the specimen, and the stiffness and damping of the expansion assembly being smaller than the stiffness and damping of the specimen.

[0012] The pneumatic loading structural testing machine of the disclosed embodiment is provided with an expansion assembly, which can prevent the pneumatic loading structural testing machine from affecting the free vibration of the test piece during the loading process. The expansion assembly can still maintain pressure naturally after expansion, and does not require a complex power system for constant adjustment, thereby reducing the vibration noise of the loading device itself and improving the accuracy of the test results.

[0013] In some embodiments, the pneumatic loading structural testing machine further includes a first detection component, which is disposed in the second cavity and between the specimen and the loading plate, and the first detection component is used to detect the force exerted by the loading plate on the specimen, and / or, the pneumatic loading structural testing machine further includes a second detection component, which is located in the second cavity and on the side of the specimen away from the loading plate, and the second detection component is used to detect the force exerted by the loading plate on the specimen.

[0014] In some embodiments, the expansion assembly includes multiple expansion units, and the multiple expansion units are arranged in the first cavity or the second cavity in sequence along the circumference of the first cavity. The expansion assembly has a first state and a second state. In the first state, the expansion medium passed into the two adjacent expansion units is the same. In the second state, the expansion medium passed into the two adjacent expansion units is different.

[0015] In some embodiments, the pneumatic loading structural testing machine further includes a vibration assembly, which is disposed in the second cavity on a side of the specimen away from the loading plate. The vibration assembly can emit a vibration signal to drive the specimen to vibrate.

[0016] In some embodiments, the pneumatic loading structural testing machine also includes: a third detection component, the third detection component is arranged in the loading plate, and the third detection component is used to detect the vibration signal on one side of the specimen; a fourth detection component, the fourth detection component is arranged in the second cavity and is located on the side of the specimen away from the loading plate, and the fourth detection component is used to detect the vibration signal on the other side of the specimen.

[0017] In some embodiments, the reaction beam is movable relative to the support portion and along the extension direction of the support portion, and the pneumatic loading structural testing machine also includes a positioning member, which is detachably connected to the support portion and the reaction beam respectively, so that the reaction beam can be adjusted on the support portion along the height direction of the reaction frame through the positioning member.

[0018] In some embodiments, the length direction of the reaction frame is the up and down direction, the first cavity is located above the second cavity, the expansion component is arranged in the first cavity and the upper and lower sides of the expansion component are connected to the reaction beam and the loading plate, so that the expansion component expands to adjust the pressure on the specimen. The expansion component is in a first state, and the amount of expansion medium introduced into the two adjacent expansion units is the same, and pressure is evenly applied to the loading plate.

[0019] In some embodiments, the length direction of the reaction frame is the up and down direction, the first cavity is located above the second cavity, the expansion assembly is arranged in the second cavity and is connected to the loading plate, and the loading plate is connected to the specimen so that the expansion assembly expands to adjust the tension applied to the specimen. The expansion assembly is in a first state, and the amount of expansion medium introduced into the two adjacent expansion units is the same, and uniform pressure is applied to the loading plate.

[0020] In some embodiments, the length direction of the reaction frame is horizontal, the first cavity and the second cavity are arranged in sequence along the horizontal direction, the pneumatic loading structure testing machine also includes a beam extending along the length direction of the reaction frame, the beam is arranged in the second cavity and is connected to the loading plate, the expansion assembly is arranged in the first cavity and is connected to the reaction beam and the loading plate, so that the loading plate drives the beam to move along the length direction of the reaction frame, the specimen is arranged between the beam and the bottom of the support part, the upper end of the specimen is connected to the bottom surface of the beam, so that the loading plate applies shear force to the specimen through the beam, the expansion assembly is in a first state, and the amount of expansion medium passed into the two adjacent expansion units is the same, so as to uniformly apply pressure to the loading plate.

[0021] In some embodiments, the pneumatic loading structural testing machine also includes a rotating shaft, which is passed through the loading plate and rotatably arranged in the reaction frame. The expansion assembly includes a first expansion unit, a second expansion unit, a third expansion unit and a fourth expansion unit. The first expansion unit and the second expansion unit are both arranged in the reaction frame, and the first expansion unit and the second expansion unit are both arranged in the first cavity and spaced apart along the length direction of the reaction frame. The rotating shaft is located between the first expansion unit and the second expansion unit. The specimen and the rotating shaft are arranged relative to each other in the width direction of the reaction frame. The third expansion unit and the fourth expansion unit are arranged in the second cavity. The third expansion unit and the first expansion unit are arranged relative to each other in the width direction of the reaction frame. The fourth expansion unit and the second expansion unit are arranged relative to each other in the width direction of the reaction frame. The specimen is arranged between the third expansion unit and the fourth expansion unit. The expansion assembly is in the second state, and the amount of expansion medium passed into the two expansion units in the same cavity is different. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG1 is a schematic structural diagram of a pneumatic loading structural testing machine according to a first embodiment of the present disclosure.

[0023] FIG2 is a schematic cross-sectional structural diagram of portion 1-1 in FIG1 provided by an embodiment of the present disclosure.

[0024] FIG3 is a schematic cross-sectional structural diagram of portion 2-2 in FIG1 provided by an embodiment of the present disclosure.

[0025] FIG4 is a schematic cross-sectional structural diagram of portion 3-3 in FIG1 provided by an embodiment of the present disclosure.

[0026] FIG5 is a schematic cross-sectional structural diagram of portion 4-4 in FIG1 provided by an embodiment of the present disclosure.

[0027] FIG6 is a schematic cross-sectional structural diagram of portion 5-5 in FIG1 provided by an embodiment of the present disclosure.

[0028] FIG7 is a schematic diagram of the installation of the first detection assembly and the third detection assembly of the pneumatic loading structural testing machine according to the first embodiment of the present disclosure.

[0029] FIG8 is a schematic diagram of the installation of the second detection assembly and the fourth detection assembly of the pneumatic loading structural testing machine according to the first embodiment of the present disclosure.

[0030] FIG9 is a schematic diagram of the installation of the vibration assembly of the pneumatic loading structural testing machine according to the first embodiment of the present disclosure.

[0031] FIG10 is a side view of the pneumatic loading structural testing machine according to the first embodiment of the present disclosure.

[0032] FIG11 is a schematic structural diagram of a pneumatic loading structural testing machine according to a second embodiment of the present disclosure.

[0033] FIG12 is a schematic structural diagram of a pneumatic loading structural testing machine according to a third embodiment of the present disclosure.

[0034] FIG13 is a cross-sectional view of a pneumatic loading structural testing machine according to a third embodiment of the present disclosure.

[0035] FIG14 is a schematic structural diagram of a pneumatic loading structural testing machine according to a fourth embodiment of the present disclosure.

[0036] FIG15 is a schematic structural diagram of the expansion assembly of the pneumatic loading structural testing machine according to an embodiment of the present disclosure.

[0037] Air pressure loading structural testing machine 100;

[0038] Reaction frame 1; reaction beam 11; reaction main beam 111; reaction secondary beam 112; support portion 12; support rod 121; first cavity 122; second cavity 123; bottom plate 13;

[0039] Loading plate 2; limiting wheel 21;

[0040] Expansion assembly 3; first expansion unit 31; second expansion unit 32; third expansion unit 33; fourth expansion unit 34; connecting plate 35

[0041] First detection component 4; second detection component 5;

[0042] Vibration assembly 6;

[0043] The third detection assembly 7 ; the fourth detection assembly 8 ; the crossbeam 9 ; the rotating shaft 10 ; the first hanging ring 101 ; the second hanging ring 102 ; and the test piece 103 . DETAILED DESCRIPTION

[0044] The embodiments of the present disclosure are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present disclosure, but should not be understood as limiting the present disclosure.

[0045] A pneumatic loading structural testing machine according to an embodiment of the present disclosure will be described below with reference to the accompanying drawings.

[0046] As shown in FIG. 1-15 , a pneumatic loading structural testing machine 100 according to an embodiment of the present disclosure includes a reaction frame 1 , a loading plate 2 , and an expansion assembly 3 .

[0047] The reaction frame 1 includes a reaction beam 11 and a support portion 12. The reaction beam 11 is mounted on the support portion 12. As shown in Figures 1-2, the support portion 12 includes a plurality of rigid support rods 121. The support rods 121 are spaced apart in the left-right or front-back directions to form a support frame and surround a loading space within the support portion 12. The reaction beam 11 is mounted on a horizontal surface at a certain height within the loading space. The reaction beam 11 is rigid and fixedly mounted within the support portion 12.

[0048] Loading plate 2 is disposed on support portion 12 and spaced apart from reaction beam 11 along the extension direction of support portion 12 to form a first cavity 122. The side of loading plate 2 facing away from reaction beam 11 forms a second cavity 123 with reaction frame 1. In other words, loading plate 2 divides support portion 12 into first cavity 122 and second cavity 123. Loading plate 2 is movable relative to reaction frame 1 along the length of reaction frame 1 or rotatable relative to reaction frame 1 about an axis perpendicular to the length of reaction frame 1. As shown in Figures 1-15, the loading plate 2 can be set according to actual conditions. For example, as shown in Figures 1 and 11, when the reaction frame 1 is vertically installed on the ground, that is, the length direction of the reaction frame 1 is vertical, the loading plate 2 is a horizontal plate and the support part 12 is divided into a first cavity 122 and a second cavity 123 arranged along the up and down directions. As shown in Figures 12 and 14, when the reaction frame 1 is horizontally installed on the bottom surface, that is, the length direction of the reaction frame 1 is horizontal, the loading plate 2 is a vertical plate and the support part 12 is divided into a first cavity 122 and a second cavity 123 arranged along the left and right directions. The movement of the loading plate 2 can be carried out in the up and down direction or the left and right direction according to the test needs, or it can be rotated around the front and back directions.

[0049] Expansion assembly 3 is disposed within at least one of first chamber 122 and second chamber 123. Second chamber 123 is suitable for mounting specimen 103, with specimen 103 abutting against loading plate 2. Expansion assembly 3 is adapted to be filled with an expansion medium to adjust the force exerted by loading plate 2 on specimen 103. The stiffness and damping of expansion assembly 3 are both less than those of specimen 103. As shown in FIG1-16 , expansion assembly 3 may be an air cushion inflated with high-pressure gas. Expansion assembly 3 may be positioned within first chamber 122 or second chamber 123 depending on the actual situation. For example, as shown in FIG1 , when it is necessary to measure the pressure of the specimen 103 , the expansion assembly 3 may be disposed in the first cavity 122 so that when the expansion assembly 3 expands, it pushes the loading plate 2 to move toward the direction adjacent to the specimen 103 , thereby applying pressure to the specimen 103 through the loading plate 2 . As shown in FIG11 , when it is necessary to test the tension of the specimen 103 , the expansion assembly 3 may be disposed in the second cavity 123 so that when the expansion assembly 3 expands, it pushes the loading plate 2 to move toward the direction away from the specimen 103 , thereby applying tension to the specimen 103 through the loading plate 2 .

[0050] The pneumatic loading structural testing machine 100 of the disclosed embodiment is provided with a loading plate 2 and an expansion assembly 3. The expansion assembly 3 loads the specimen 103 via the loading plate 2. Since the stiffness of the expansion assembly 3 is much smaller than that of the structural specimen 103 and the damping of the expansion assembly 3 itself is relatively low, the expansion assembly 3 avoids affecting the free vibration of the specimen 103. Furthermore, the expansion assembly 3 can naturally maintain pressure for a period of time after expansion is completed, without the need for a complex power system to constantly adjust it. This makes the pneumatic loading structural testing machine 100 itself essentially free of vibration noise, thereby effectively resolving the problems in related technologies of structural testing machines being unable to achieve high-pressure, low-constraint vertical compression loading, and the significant interference of the testing machine with the vibration signal collection of the specimen 103, thereby improving the accuracy of the test.

[0051] In the pneumatic loading structural testing machine 100 of the embodiment of the present disclosure, the force acting on the test piece 103 mainly comes from the pressure generated by the expansion of the expansion component 3. After the pressurization is completed, the expansion component 3 naturally maintains the pressure. The pneumatic loading structural testing machine 100 is in a static state with low vibration and noise. This is because the compression stiffness of the expansion component 3 is small and sufficient pressure can be applied by filling it with an expansion medium. In addition, it can better simulate the working state of structural components such as supports in actual engineering projects, where they are only subjected to vertical pressure and not constrained by upper displacement.

[0052] In some embodiments, the reaction beam 11 includes two reaction main beams 111 and multiple reaction secondary beams 112. The two ends of the reaction main beam 111 are respectively connected to the two vertical support rods 121 by bolts. The two ends of each reaction secondary beam 112 are respectively connected to the two reaction main beams 111. The bottom surfaces of the reaction main beam 111 and the reaction secondary beam 112 are in the same plane. The two ends of the reaction main beam 111 are respectively connected to the two vertical support rods 121 by bolts. It can be understood that by selecting bolt holes at different heights for bolt connection, the reaction beam 11 can be arranged at different heights, changing the height of the loading space in the support part 12, and flexibly adapting to the loading requirements of the test pieces 103 of different heights.

[0053] In some embodiments, the support parts 12 can be provided in different quantities and in different structural arrangements according to actual conditions, such as providing column feet for the vertical support parts 12 .

[0054] In some embodiments, the loading plate 2 is composed of two upper and lower steel plates and a certain number of vertical stiffening ribs. The loading plate 2 has a large rigidity so that its deformation under the action of the air cushion pressure can be ignored. When the loading plate 2 moves or rotates, the pressure of the expansion assembly 3 is transmitted to the test piece 103.

[0055] In some embodiments, the loading plate 2 adopts different structural arrangements to ensure rigidity, such as a reinforced concrete plate. In addition, the loading plate 2 can also adopt different forms to limit its rotation and displacement in the horizontal plane.

[0056] In some embodiments, the pneumatic loading structural testing machine 100 has two types: a self-balancing configuration and a non-self-balancing configuration.

[0057] In the self-balancing configuration, the bottom of the reaction frame 1 has a bottom plate 13, which is connected to the bottom of the support portion 12. The bottom plate 13, the support portion 12 and the reaction beam 11 surround and form a loading space within the support portion 12. The bottom plate 13 and the reaction frame 1 are spaced apart to define a second cavity 123. In the self-balancing configuration, the pressure of the specimen 103 acts downward on the bottom plate 13. In other words, in the self-balancing configuration, the pressure of the specimen 103 acts downward on the inside of the reaction frame 1.

[0058] In the non-self-balancing configuration, the bottom of support portion 12 is connected to the ground, and the ground and reaction frame 1 are spaced apart to define a second cavity 123. Test specimen 103 is placed on the ground within the loading space. In the non-self-balancing configuration, the pressure of test specimen 103 acts downward on the ground, i.e., outside reaction frame 1.

[0059] In some embodiments, the reaction frame 1 is provided with four spaced-apart support rods 121 as vertical support portions 12, which enclose a loading space. A reaction beam 11 is mounted on a horizontal plane at a certain height within the loading space. The reaction beam 11 comprises two main reaction beams 111 and several secondary reaction beams 112. The ends of the main reaction beams 111 are connected to the two vertical support portions 12 via bolts. Each secondary reaction beam 112 is connected to two main reaction beams 111 at both ends, with the bottom surfaces of the main reaction beams 111 and the secondary reaction beams 112 being coplanar.

[0060] In some embodiments, the pneumatic loading structural testing machine 100 further includes a first detection assembly 4, which is disposed within the second chamber 123 and between the specimen 103 and the loading plate 2. The first detection assembly 4 is used to detect the force exerted by the loading plate 2 on the specimen 103. Specifically, the first detection assembly 4 is an axial pressure sensor and is disposed within the second chamber 123. The first detection assembly 4 is also disposed on the loading plate 2 and between the loading plate 2 and the specimen 103. Thus, the first detection assembly 4 collects and outputs a vertical pressure load signal exerted on the loading plate 2, allowing the actual pressure exerted by the expansion assembly 3 on the loading plate 2 to be accurately determined at all times during the test, providing a reference for adjusting the air pressure of the expansion assembly 3.

[0061] In some embodiments, the pneumatic loading structural testing machine 100 further includes a second detection assembly 5 . The second detection assembly 5 is located within the second chamber 123 and on the side of the specimen 103 away from the loading plate 2 . The second detection assembly 5 is used to detect the force exerted by the loading plate on the specimen 103 . In some embodiments, the second detection assembly 5 is an axial pressure sensor. In the self-balancing configuration, the second detection assembly 5 is disposed on the base plate 13 and is located between the specimen 103 and the base plate 13 . In the non-self-balancing configuration, the second detection assembly 5 is disposed on the ground and is located between the specimen 103 and the ground. The second detection assembly 5 is connected to the specimen 103 and is used to measure the vertical pressure load applied to the specimen 103 .

[0062] In some embodiments, the pneumatic loading structural testing machine 100 further includes a vibration assembly 6 , which is disposed within the second chamber 123 on a side of the specimen 103 away from the loading plate 2 . The vibration assembly 6 is configured to emit a vibration signal to drive the specimen 103 to vibrate. As shown in FIG9 , the vibration assembly 6 is a vibration signal generator. In a self-balancing configuration, the vibration assembly 6 is disposed on the base plate 13 and positioned between the specimen 103 and the base plate 13 . In a non-self-balancing configuration, the vibration assembly 6 is disposed on the ground and positioned between the specimen 103 and the ground. The vibration assembly 6 can generate a vibration signal to test the dynamic characteristics of the structural specimen 103 .

[0063] In some embodiments, the pneumatic loading structural testing machine 100 further includes a third detection component 7 and a fourth detection component 8 .

[0064] The third detection assembly 7 is arranged in the loading plate 2, and the third detection assembly 7 is used to detect the vibration signal on one side of the test piece 103. The fourth detection assembly 8 is arranged in the second cavity 123 and is located on the side of the test piece 103 away from the loading plate 2. The fourth detection assembly 8 is used to detect the vibration signal on the other side of the test piece 103. As shown in Figures 7 and 8, the third detection assembly 7 and the fourth detection assembly 8 are both vibration signal collectors, and the third detection assembly 7 is arranged on the loading plate 2. In the self-balancing configuration, the fourth detection assembly 8 is arranged on the bottom plate 13 and is located between the test piece 103 and the bottom plate 13. In the non-self-balancing configuration, the fourth detection assembly 8 is arranged on the ground and is located between the test piece 103 and the ground. Thus, the third detection assembly 7 and the fourth detection assembly 8 respectively detect the vibration signals (e.g., vibration frequency, vibration intensity, etc.) on both sides of the test specimen 103. The third detection assembly 7 and the fourth detection assembly 8 obtain a transfer function by detecting the changes in the vibration waves before and after the test specimen 103, and then analyze the characteristic frequency of the test specimen 103. Based on the transfer function, the dynamic characteristics of the test specimen 103 can be obtained. Therefore, through the coordination of the first detection assembly 4, the second detection assembly 5, the vibration assembly 6, the third detection assembly 7, and the fourth detection assembly 8, the free vibration of the test specimen 103 or the vertical vibration response under external excitation can be measured, and the dynamic performance of the structural test specimen can be accurately measured.

[0065] It should be noted that multiple vibration components 6, third detection components 7 and fourth detection components 8 can be arranged, but at most one vibration component 6 generator is usually in working state at the same time to prevent the simultaneous existence of multiple signal vibration sources and increase the difficulty of analysis. By simultaneously collecting the vibration signals of the base plate 13 and the loading plate 2, the transfer function of the vibration signal in the test piece 103 can be analyzed, and then the characteristic frequency of the test piece 103 can be analyzed. In addition, by evenly arranging the third detection component 7 and the fourth detection component 8 at multiple points, the characteristics of the vibration signal can be obtained more accurately and completely. The fourth detection component 8 will collect the vibration signal actually output by the vibration component 6 to avoid errors in the vibration component 6 and changes in the vibration signal generation mechanism that may occur after the test piece 103 is installed.

[0066] In some embodiments, the reaction beam 11 is movable relative to the support portion 12 and along the extension direction of the support portion 12. The pneumatic loading structural testing machine 100 further includes a positioning member, which is detachably connected to the support portion 12 and the reaction beam 11, respectively, so that the reaction beam 11 can be adjusted along the height direction of the reaction frame 1 on the support portion 12 via the positioning member. As shown in Figure 1, the reaction beam 11 is detachably mounted on the support portion 12 via the positioning member and is movable in the vertical direction and is positioned by the positioning member, thereby adjusting the position of the reaction beam 11 on the support portion 12.

[0067] The pneumatic loading structural testing machine 100 of the embodiment of the present disclosure does not impose any restrictions on the support part 12. For example, an array of slots at different heights are arranged on the side of the support part 12 along the length direction, and the reaction beam 11 is fixed at different heights by the slots, or the positioning member can be a screw or bolt, and the support part 12 and the reaction beam 11 are connected by screws or bolts, thereby adjusting the height of the reaction beam 11.

[0068] In some embodiments, a slide rail extending along the extension direction of the support portion 12 is provided on the side of the support portion 12 facing the loading plate 2. The loading plate 2 is provided with a limiting wheel 21 that slidably cooperates with the slide rail, so that the loading plate 2 can move along the extension direction of the support portion 12. As shown in Figures 1-13, the inner sides of the four support rods 121 are each provided with a slide rail 121 extending along the length direction. The loading plate 2 is provided with a limiting wheel 21 that cooperates with the slide rail. The limiting wheel 21 is fixed to the loading plate 2 as a whole via bolts. The thickness of the limiting wheel 21 matches the width of the slide rail. The limiting wheels 21 at the four corners of the loading plate 2 are respectively inserted into the slide rail, and the limiting wheels 21 can move along the arrangement direction of the slide rail, that is, the vertical direction. Thus, the slide rail and the limiting wheel 21 cooperate to form a limiting device, which prevents the loading plate 2 from moving or rotating relative to the width direction of the support portion and does not hinder the loading plate 2 from moving along the length direction of the support portion.

[0069] It can be understood that since the limiting wheel 21 is fixed to the loading plate 2 as a whole, and the limiting wheel 21 constrains the translation and rotation of the loading plate 2, it is only allowed to move relative to the length direction of the support member 121, thereby ensuring that the external force exerted on the specimen 103 comes from the expansion assembly 3, and ensuring the safety of the pneumatic loading structural testing machine 100.

[0070] In some embodiments, the expansion assembly 3 includes a plurality of expansion units, which are sequentially arranged in the first cavity 122 or the second cavity 123 along the circumference of the first cavity 122. The expansion assembly 3 has a first state and a second state. In the first state, the expansion medium introduced into two adjacent expansion units is the same, and in the second state, the expansion medium introduced into two adjacent expansion units is different. As shown in Figures 1-14, the expansion units can be arranged according to actual conditions, and the plurality of expansion units can be evenly distributed in the first cavity 122 or the second cavity 123. For example, in the first state, the expansion medium introduced into the expansion units is the same so that the air pressure in each expansion unit is equal. In the second state, the expansion medium introduced into the expansion units is different so that the air pressure in the expansion units can be different. Thus, the expansion units can be adjusted according to actual conditions, thereby adjusting the force applied to the specimen 103.

[0071] In some embodiments, the expansion assembly 3 is spherical, its top contacting the bottom of the reaction beam 11 when inflated. Four connecting plates 35 are arranged on the top surface of the loading plate 2 at appropriate intervals, depending on the shape of the air cushion. These connecting plates 35 can be bonded to the expansion assembly 3 and bolted to the top surface of the loading plate 2. This arrangement allows for flexible assembly and disassembly of different air cushions based on loading requirements, while also facilitating air cushion maintenance and ensuring the device's versatility and safety.

[0072] In some embodiments, as shown in FIG15 , the expansion components 3 have different numbers and shapes to adapt to different specifications of structural testing machines. For example, the expansion components 3 can be spherical, cylindrical, square, or any other shape.

[0073] In some embodiments, the expansion assembly 3 and the loading plate 2 are connected and fixed in different ways, such as flange connection.

[0074] In some embodiments, the reaction beam 11 is equipped with a first lifting ring 101, and the loading plate 2 is mounted on its side with a second lifting ring 102 that mates with the first lifting ring 101. Slings are respectively threaded through the first lifting ring 101 and the second lifting ring 102. Thus, when not loading, the lifting ring can pull up the loading plate 2, preventing it from falling onto the base plate 13. This ensures a certain distance between the loading plate 2 and the base plate 13, ensuring sufficient operating space for placing the test specimen 103 and removing it after the test is complete, thereby improving the ease of operation and safety of the testing machine. When loading is in progress, the lifting ring is relaxed so that the loading plate 2 only bears the driving force of the expansion assembly 3.

[0075] It should be noted that the length of the sling can be adjusted by devices such as the limiting wheel 21. During the installation of the specimen 103, the sling can be shortened to pull up the loading plate 2; after the specimen 103 is installed, the sling is extended to make the loading plate 2 fall and contact the top of the specimen 103; in the process of the loading plate 2 moving vertically downward until it contacts the specimen 103 and applies the set loading pressure, the sling has sufficient length and does not affect the vertical movement of the loading plate 2.

[0076] It is worth noting that different forms of device designs can be used to lift the loading plate 2, for example, a jack, an electric telescopic rod, a cylinder, etc. can be arranged under the loading plate 2 to lift the loading plate 2.

[0077] In some embodiments, the length direction of the reaction frame 1 is the up and down direction, the first cavity 122 is located above the second cavity 123, the expansion assembly 3 is arranged in the first cavity 122, and the upper and lower sides of the expansion assembly 3 are connected to the reaction beam 11 and the loading plate 2, so that the expansion assembly 3 expands to adjust the pressure on the specimen 103. As shown in Figures 1-10, the support portion 12 extends in the up-down direction, and the loading plate 2 is a horizontal plate to divide the support portion 12 into a first cavity 122 and a second cavity 123 in the up-down direction. The first cavity 122 is an upper cavity, and the second cavity 123 is a lower cavity. The expansion assembly 3 includes 4 expansion units (4 as shown in Figure 3) and is evenly arranged in the first cavity 122. The upper end of each expansion unit is connected to the reaction beam 11, and the lower end of each expansion unit is connected to the loading plate 2. The expansion assembly 3 is in a first state. In other words, the amount of expansion medium introduced into the two adjacent expansion units is the same, and pressure is evenly applied to the loading plate 2, so that the expansion assembly 3 expands to drive the loading plate 2 to move downward, thereby increasing the pressure of the loading plate 2 on the specimen 103. Therefore, when measuring the mechanical properties of the specimen 103, the pressure applied to the specimen 103 should be consistent with the actual usage state in the engineering.

[0078] In some embodiments, the length direction of the reaction frame 1 is the up and down direction, the first cavity 122 is located above the second cavity 123, the expansion assembly 3 is arranged in the second cavity 123 and is connected to the loading plate 2, and the loading plate 2 is connected to the specimen 103 so that the expansion assembly 3 expands to adjust the tension exerted on the specimen 103. As shown in FIG11 , the support portion 12 extends in the vertical direction, and the loading plate 2 is a horizontal plate to divide the support portion 12 into a first cavity 122 and a second cavity 123 in the vertical direction. The first cavity 122 is an upper chamber, and the second cavity 123 is a lower chamber. There are two expansion assemblies 3 (two as shown in FIG11 ), and the two expansion units are arranged in the second cavity 123 at intervals along the left-right direction. The upper end of each expansion unit is connected to the loading plate 2 (for example, by bonding, screw connection, etc.), and the lower end of each expansion unit is against the bottom plate 13 (or the ground). The loading plate 2 is connected to the upper end of the specimen 103, and the expansion assembly 3 is in a first state. In other words, the amount of expansion medium introduced into the two expansion units is the same, and pressure is uniformly applied to the loading plate 2, causing the expansion assembly 3 to expand and drive the loading plate 2 to move upward, thereby causing the loading plate 2 to apply tension to the specimen 103. Therefore, when measuring the mechanical properties of the specimen 103, the tension applied to the specimen 103 should be consistent with the actual usage state in the engineering.

[0079] In some embodiments, the length direction of the reaction frame 1 is horizontal, the first cavity 122 and the second cavity 123 are arranged in sequence along the horizontal direction, and the pneumatic loading structural testing machine 100 also includes a beam 9 extending along the length direction of the reaction frame 1, the beam 9 is arranged in the second cavity 123 and is connected to the loading plate 2, the expansion assembly 3 is arranged in the first cavity 122 and is connected to the reaction beam 11 and the loading plate 2, so that the loading plate 2 drives the beam 9 to move along the length direction of the reaction frame 1, the specimen 103 is arranged between the beam 9 and the bottom of the support part 12, the axial direction of the specimen 103 is vertical, that is, the axial direction of the specimen 103 is perpendicular to the length direction of the reaction frame 1, and the upper end of the specimen 103 is in contact with the beam 9, so that the loading plate 2 applies shear force to the specimen 103 through the beam 9. As shown in Figures 12 and 13, the reaction frame 1 is placed horizontally on the ground and extends in the left-right direction. The loading plate 2 is a vertical plate and is arranged in the support part 12 and the support part 12 is divided into a first cavity 122 and a second cavity 123 in the left-right direction. The first cavity 122 is arranged on the right side of the second cavity 123. The crossbeam 9 extends in the left-right direction and the right end of the crossbeam 9 is connected to the left end of the loading plate 2. The expansion assembly 3 may include one expansion unit or multiple expansion units. The multiple expansion units are sequentially connected in the left-right direction and are arranged in the first cavity 122. The left and right ends of the expansion assembly 3 are respectively connected to the reaction beam 11 and the loading plate 2. The expansion assembly 3 is in the first state, and the amount of expansion medium passed into the two adjacent expansion units is The same is true so as to evenly apply pressure to the loading plate 2, so that the expansion component 3 drives the loading plate 2 to move in the left and right directions and then drives the beam 9 to move in the left and right directions. The beam 9 and the side of the reaction frame 1 adjacent to the ground are spaced apart so that the specimen 103 is arranged on the side of the beam 9 and the reaction frame 1 adjacent to the ground, and the upper end face of the specimen 103 is matched with the lower end face of the beam 9. The axial direction of the specimen 103 is vertical. The horizontal thrust applied by the expansion component 3 acts on the specimen 103 in the form of shear force through the loading plate 2 and the beam 9. Therefore, when measuring the mechanical properties of the specimen 103, the shear force applied to the specimen 103 should be consistent with the actual usage state in the project. In this embodiment, the pneumatic loading tester is a shear loading tester.

[0080] In some embodiments, the pneumatic loading structural testing machine 100 further includes a rotating shaft 10, which is disposed through the loading plate 2 and rotatably disposed within the reaction frame 1. As shown in FIG14 , the rotating shaft 10 extends in the front-to-back direction and is disposed within the reaction frame 1, located at the upper end surface of the reaction frame 1. The rotating shaft 10 penetrates the middle portion of the loading plate 2, which extends in the left-to-right direction. The outer circumference of the loading plate 2 is spaced from the inner circumference of the reaction frame 1 on both sides, thereby allowing the loading plate 2 to rotate within the reaction frame 1 via the rotating shaft 10.

[0081] In some embodiments, the expansion assembly 3 includes a first expansion unit 31, a second expansion unit 32, a third expansion unit 33 and a fourth expansion unit 34. The first expansion unit 31 and the second expansion unit 32 are both arranged in the reaction frame 1. The first expansion unit 31 and the second expansion unit 32 are both arranged in the first cavity 122 and are spaced apart along the length direction of the reaction frame 1. The rotating shaft 10 is located between the first expansion unit 31 and the second expansion unit 32. The specimen 103 and the rotating shaft 10 are arranged opposite to each other in the width direction of the reaction frame 1. The third expansion unit 33 and the fourth expansion unit 34 are arranged in the second cavity 123. The third expansion unit 33 and the first expansion unit 31 are arranged opposite to each other in the width direction of the reaction frame 1. The fourth expansion unit 34 and the second expansion unit 32 are arranged opposite to each other in the width direction of the reaction frame 1. The specimen 103 is arranged between the third expansion unit 33 and the fourth expansion unit 34. As shown in FIG14 , the first expansion unit 31, the second expansion unit 32, the third expansion unit 33, and the fourth expansion unit 34 are all air cushions. The first expansion unit 31 and the third expansion unit 33 are located at the left end of the loading plate 2, with the first expansion unit 31 located on the upper end surface of the loading plate 2 and the third expansion unit 33 located on the lower end surface of the loading plate 2. The second expansion unit 32 and the fourth expansion unit 34 are located at the right end of the loading plate 2, with the second expansion unit 32 located on the upper end surface of the loading plate 2 and the fourth expansion unit 34 located on the lower end surface of the loading plate 2. The specimen 103 is located below the loading plate 2 and in the middle of the loading plate 2. Thus, the arrangement of the first expansion unit 31, the second expansion unit 32, the third expansion unit 33, and the fourth expansion unit 34 can drive the loading plate 2 to rotate, thereby applying a bending moment to the specimen 103. Therefore, when measuring the mechanical properties of the specimen 103, the bending moment applied to the specimen 103 should be consistent with the actual use conditions in engineering.

[0082] As shown in FIG14 , when the rotating shaft 10 is a horizontal axis, the pneumatic loading tester in this embodiment is a bending moment loading tester. The pneumatic loading tester in the embodiment can be laid flat, that is, the rotating shaft 10 becomes a vertical axis. At this time, the pneumatic loading tester is a structural torque loading tester. In this case, the expansion assembly 3 is in the second state, and the amount of expansion medium introduced into the two expansion units in the same cavity is different. In other words, the amount of expansion medium introduced into the first expansion unit 31 and the second expansion unit 32 in the first cavity 122 is different, while the amount of expansion medium introduced into the third expansion unit 33 and the fourth expansion unit 34 in the second cavity 123 is different. However, the amount of expansion medium introduced into the axis of the first expansion unit 31 and the fourth expansion unit 34 is the same, and the amount of expansion medium introduced into the axis of the second expansion unit 32 and the third expansion unit 33 is the same. The left end of the loading plate is subjected to the combined thrust from the first expansion unit 31 and the third expansion unit 33 , and the right end is subjected to the combined thrust from the second expansion unit 32 and the fourth expansion unit 34 . The two combined thrusts are equal in magnitude but opposite in direction, and the loading plate 2 is subjected to a bending moment around the rotation axis 10 .

[0083] It's worth noting that torque is a special type of bending moment. The stress induced in specimen 103 by torque in structural engineering is primarily shear stress, typically causing specimen 103 to rotate about its primary axis. Bending moment, on the other hand, induces primarily tensile and compressive stresses in specimen 103, causing specimen 103 to bend within a plane passing through its primary axis. Since the test machine in the disclosed embodiment primarily tests specimen 103 to withstand vertical forces, it can be assumed that the primary axis of specimen 103 is vertical. Therefore, torque is defined as the moment axis along a vertical line, while bending moment is defined as the moment axis along a horizontal line.

[0084] The working principle of the pneumatic loading structural testing machine 100 of the first embodiment of the present disclosure is as follows:

[0085] When conducting a vibration test using the pneumatic loading structural testing machine 100 disclosed herein, after the specimen 103 is placed on the ground or at the center of the base plate 13, it is still a certain distance from the movable loading plate 2 above it. The air supply port is used to inflate and pressurize the air cushion, increasing the height of the expansion assembly 3. After the upper surface of the expansion assembly 3 contacts the bottom of the reaction beam 9 and generates pressure, the lower surface of the expansion assembly 3 applies a downward thrust to the movable loading plate 2, causing it to move vertically downward until it contacts the specimen 103. The upper and lower surfaces of the specimen 103 are respectively subjected to pressure from the movable loading plate 2 and the base plate 13 or the ground. By adjusting the amount of gas injected into the cavity of the expansion assembly 3 and monitoring the output signals of the first inspection assembly 4 and the second detection assembly 5, the pressure applied to the specimen 103 can be accurately adjusted. Because the expansion assembly 3 has relatively low stiffness and damping, the present invention can accurately simulate the boundary conditions of the specimen 103 vibrating within the structure. After the pressure loading of the specimen 103 is completed, the vibration component 6 arranged on the base plate 13 or the ground outputs a vibration signal and passes through the specimen 103 and the mobile loading plate 2 in sequence, and is finally received by the third detection component 7 and the fourth detection component 8 arranged in the mobile loading plate 2. The characteristic frequency of the specimen 103 can be determined by analyzing the transfer function between the vibration signal emitted by the vibration component 6 and the vibration signal received by the third detection component 7 and the fourth detection component 8.

[0086] In the description of the present disclosure, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present disclosure.

[0087] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. Throughout the present disclosure, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0088] In this disclosure, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections, electrical connections, or communication between them; direct connections or indirect connections through an intermediate medium; and internal communication between two elements or interaction between two elements, unless otherwise expressly limited. Those skilled in the art will understand the specific meanings of the above terms in this disclosure based on specific circumstances.

[0089] In the present disclosure, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0090] In the present disclosure, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0091] Although the embodiments of the present disclosure have been shown and described above, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present disclosure. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present disclosure.

Claims

1. A pneumatic loading structural testing machine, comprising: A reaction frame, the reaction frame comprising a reaction beam and a support portion, the reaction beam being arranged on the support portion; A loading plate, the loading plate is disposed on the support portion and is spaced apart from the reaction beam along the extension direction of the support portion to form a first cavity, a side of the loading plate away from the reaction beam forms a second cavity with the reaction frame, the loading plate is movable relative to the reaction frame along the length direction of the reaction frame, or the loading plate is rotatable relative to the reaction frame around the width direction of the reaction frame; An expansion component is arranged in at least one of the first cavity and the second cavity, the second cavity is suitable for installing a test piece and the test piece is against the loading plate, the expansion component is suitable for passing an expansion medium to adjust the force of the loading plate on the test piece, and the stiffness and damping of the expansion component are both smaller than the stiffness and damping of the test piece.

2. The pneumatic loading structural testing machine according to claim 1, further comprising a first detection assembly, the first detection assembly being disposed in the second cavity and between the test piece and the loading plate, the first detection assembly being used to detect the force exerted by the loading plate on the test piece, And / or, the pneumatic loading structural testing machine also includes a second detection component, which is located in the second cavity and on the side of the specimen away from the loading plate, and the second detection component is used to detect the force of the loading plate on the specimen.

3. The pneumatic loading structural testing machine according to claim 1, wherein: The expansion assembly includes a plurality of expansion units, and the plurality of expansion units are sequentially arranged in the first cavity or the second cavity along the circumference of the first cavity. The expansion assembly has a first state and a second state. In the first state, the expansion medium passed into two adjacent expansion units is the same, and in the second state, the expansion medium passed into two adjacent expansion units is different.

4. The pneumatic loading structural testing machine according to claim 1 further comprises a vibration assembly; wherein: The vibration component is arranged in the second cavity at a side of the test piece away from the loading plate, and the vibration component can emit a vibration signal to drive the test piece to vibrate.

5. The pneumatic loading structural testing machine according to any one of claims 1 to 4, further comprising: A third detection component, the third detection component is arranged in the loading plate, and the third detection component is used to detect the vibration signal of one side of the test piece; A fourth detection component is disposed in the second cavity and located on a side of the test piece away from the loading plate, and is used to detect a vibration signal on the other side of the test piece.

6. The pneumatic loading structural testing machine according to claim 1, wherein: The reaction beam is movable relative to the support portion and along the extension direction of the support portion. The pneumatic loading structure testing machine also includes a positioning member, which is detachably connected to the support portion and the reaction beam respectively, so that the reaction beam can be adjusted on the support portion along the height direction of the reaction frame through the positioning member.

7. The pneumatic loading structural testing machine according to claim 1, wherein: The length direction of the reaction frame is the up and down direction, the first cavity is located above the second cavity, the expansion component is arranged in the first cavity and the upper and lower sides of the expansion component are connected to the reaction beam and the loading plate, so that the expansion component expands to adjust the pressure on the specimen.

8. The pneumatic loading structural testing machine according to claim 1, wherein: The length direction of the reaction frame is the up-down direction, the first cavity is located above the second cavity, the expansion assembly is arranged in the second cavity and connected to the loading plate, and the loading plate is connected to the specimen so that the expansion assembly expands to adjust the tension exerted on the specimen.

9. The pneumatic loading structural testing machine according to claim 1, wherein: The length direction of the reaction frame is horizontal, and the first cavity and the second cavity are arranged in sequence along the horizontal direction. The pneumatic loading structural testing machine also includes a crossbeam extending along the length direction of the reaction frame, the crossbeam is arranged in the second cavity and connected to the loading plate, the expansion assembly is arranged in the first cavity and connected to the reaction beam and the loading plate, so that the loading plate drives the crossbeam to move along the length direction of the reaction frame, the test piece is arranged between the crossbeam and the bottom of the support part, and the upper end of the test piece is connected to the bottom surface of the crossbeam, so that the loading plate applies shear force to the test piece through the crossbeam.

10. The pneumatic loading structural testing machine according to claim 1 further comprises a rotating shaft; wherein: The rotating shaft is disposed through the loading plate and is rotatably disposed in the reaction frame. The expansion assembly includes a first expansion unit, a second expansion unit, a third expansion unit and a fourth expansion unit, the first expansion unit and the second expansion unit are both arranged in the reaction frame, the first expansion unit and the second expansion unit are both arranged in the first cavity and are spaced apart along the length direction of the reaction frame, the rotating shaft is located between the first expansion unit and the second expansion unit, and the test piece and the rotating shaft are arranged opposite to each other in the width direction of the reaction frame, The third expansion unit and the fourth expansion unit are arranged in the second cavity, the third expansion unit and the first expansion unit are arranged relative to each other at a width interval of the reaction frame, the fourth expansion unit and the second expansion unit are arranged relative to each other at a width interval of the reaction frame, the test piece is arranged between the third expansion unit and the fourth expansion unit, the expansion assembly is in the second state, and the amounts of expansion medium introduced into the two expansion units in the same cavity are different.

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