A device for preventing instability suitable for large-scale structural engineering tests

Abstract

The present application is suitable for the technical field of structure test, and provides a device for preventing instability suitable for large-scale structure test, which comprises: a pad assembly for supporting a test piece, the pad assemblies are connected through a binding assembly; a support assembly connected with one end of the pad assembly for providing lateral constraint force; a self-propelled assembly connected with the other end of the support assembly, the test piece drives the support assembly to deviate when deviating, and the self-propelled assembly moves the support point synchronously under the deviation of the support assembly; the pad assembly comprises: a follower closely attached to the test piece; a horizontal piece connected with the support assembly, the follower is movably connected with the horizontal piece, and the follower rotates relative to the horizontal piece when the test piece tilts, for preventing the support assembly from being twisted. The present application ensures that the pad assembly can always provide lateral constraint force even if the test piece tilts during the structure test, and the self-propelled assembly can move the support point synchronously with the movement of the test piece, avoiding that the test piece is pulled by the support assembly due to too large bending degree.

Description

Technical Field

[0001] This invention belongs to the field of structural testing technology, and in particular relates to an anti-instability device suitable for large-scale structural engineering tests. Background Technology

[0002] To promote the development of prefabricated buildings, numerous large-scale structural engineering tests are conducted in the construction field. However, in these tests, specimen instability is unexpected and detrimental, often leading to test failure, inaccurate data, and even posing dangers to the structural tests, endangering the safety of personnel and equipment, and causing property damage. Therefore, the existence and innovation of anti-instability devices for structural tests are of great significance.

[0003] Currently, there are few solutions for specimen instability in large-scale structural engineering tests. They can be basically divided into two categories. The mainstream method is to install four orthogonal steel beams based on reaction frame columns or by erecting additional columns. The steel beams are then arranged along the edge of the specimen and pressed tightly against it to prevent out-of-plane instability. This method of preventing specimen instability has two drawbacks: first, the specimen and the steel beams are tightly fitted, making it difficult to control friction; second, the anti-instability device is quite bulky, with some devices even larger than the test specimen, resulting in high manufacturing costs. Moreover, the installation and disassembly of large specimens at heights in multiple locations greatly increases the danger of the test. To address the first drawback, ball bearings or rollers are added between the specimen and the steel beams to reduce friction. However, this approach results in a large, expensive, cumbersome, and dangerous instability device.

[0004] Another method involves stringing steel strands between the specimen and bolts on the ground, with symmetrical steel strands on both sides. To ensure safety, two steel strands are typically used and secured with clips, one bearing the load and the other not, to prevent breakage and injury. While relatively simple and inexpensive, this method has drawbacks. It is extremely difficult to control the length of the steel strands on both sides of the specimen to prevent it from tilting to one side. Furthermore, under the horizontal load of the actuator, there are too many uncontrollable factors. In addition, although this solution is simple, it is very dangerous. In the initial position, when the steel strands are taut, if the specimen undergoes a large horizontal displacement, the steel strands will be under severe tension and may suddenly break, leading to experimental failure. Summary of the Invention

[0005] The purpose of this invention is to provide an anti-instability device suitable for large-scale structural engineering tests, aiming to solve the problems existing in the background art.

[0006] The present invention is implemented as follows: an anti-instability device suitable for large-scale structural engineering tests, the device comprising:

[0007] A pad assembly for supporting the specimen, wherein there are at least two sets of pad assemblies connected to each other by a binding assembly;

[0008] A support assembly, one end of which is connected to the pad assembly, for providing lateral restraint force;

[0009] The self-propelled component is connected to the other end of the support component. When the specimen shifts, it causes the support component to shift. The self-propelled component moves the support point synchronously under the shift of the support component.

[0010] The pad assembly includes:

[0011] Follower component, which is attached to the test specimen;

[0012] A horizontal component is connected to a support assembly, and a following component is movably connected to the horizontal component. When the specimen tilts, the following component rotates relative to the horizontal component to prevent the support assembly from twisting.

[0013] This invention provides an anti-instability device suitable for large-scale structural engineering tests. It utilizes a pad assembly to adhere tightly to the specimen, releasing torque and ensuring that even if the specimen tilts during structural testing, the pad assembly always provides lateral constraint. A support assembly supports the pad assembly and can be arbitrarily assembled according to the specimen height. It is simple to use and easy to store. A self-propelled assembly moves the support point synchronously with the specimen, preventing excessive bending of the specimen from causing the support assembly to pull on the specimen and resulting in inaccurate data measurements. A binding assembly connects the pad assembly and the specimens between the pad assemblies, is convenient to use, can be extended, and adapts to specimens of different shapes and sizes. Attached Figure Description

[0014] Figure 1 A schematic diagram of an anti-instability device suitable for large-scale structural engineering tests provided in this embodiment of the invention;

[0015] Figure 2 This is a schematic diagram of the pad assembly in an anti-instability device suitable for large-scale structural engineering tests provided by an embodiment of the present invention;

[0016] Figure 3 This is a schematic diagram of the follower component in an anti-instability device suitable for large-scale structural engineering tests, provided by an embodiment of the present invention.

[0017] Figure 4 This is a schematic diagram of the horizontal component in an anti-instability device suitable for large-scale structural engineering tests, provided by an embodiment of the present invention.

[0018] Figure 5 This is a schematic diagram of the support component in an anti-instability device suitable for large-scale structural engineering tests, provided by an embodiment of the present invention.

[0019] Figure 6This is a schematic diagram of the structure of an anti-instability device suitable for large-scale structural engineering tests provided by an embodiment of the present invention, showing the connection head and the pin before they are engaged.

[0020] Figure 7 This is a schematic diagram of the support rod in an anti-instability device suitable for large-scale structural engineering tests, provided by an embodiment of the present invention.

[0021] Figure 8 This is a schematic diagram of the structure of a self-propelled component in an anti-instability device suitable for large-scale structural engineering tests, provided by an embodiment of the present invention.

[0022] Figure 9 This invention provides a schematic diagram of the structure of a laser lamp and a walking pole working together in an anti-instability device suitable for large-scale structural engineering tests.

[0023] Figure 10 This is a schematic diagram of the binding component in an anti-instability device suitable for large-scale structural engineering tests, provided by an embodiment of the present invention.

[0024] Figure 11 This is a schematic diagram of the adjusting component in an anti-instability device suitable for large-scale structural engineering tests, provided by an embodiment of the present invention.

[0025] Figure 12 This invention provides a diagram showing the operational relationship between the pad assembly, support assembly, and specimen in an anti-instability device suitable for large-scale structural engineering tests.

[0026] Figure 13 This is another diagram showing the operational relationship between the pad assembly, the support assembly, and the specimen in an anti-instability device suitable for large-scale structural engineering tests, provided by an embodiment of the present invention.

[0027] Figure 14 Force diagram of the experimental model provided in the embodiment of the present invention.

[0028] In the attached diagram: 1-Pad assembly; 101-First plate; 102-Second plate; 103-Intermediate plate; 104-Shaft pin; 105-Insertion plate; 106-Ear plate; 2-Support assembly; 201-Connector; 202-Pin; 203-Support end; 20301-Laser lamp; 204-Support rod; 3-Self-propelled assembly; 301-Traveling rod; 30101-Photosensitive element; 30102-Circuit board; 30103-Power supply; 30104-Gear; 302-Crossbar; 303-Base; 4-Binding assembly; 401-Connecting strap; 402-Adjusting component; 40201-First bevel gear; 40202-Second bevel gear; 40203-Rotating rod; 40204-Snap fastener; 403-Connector. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0030] In large-scale structural engineering tests, the mainstream anti-instability treatment method is the first type, which involves installing four orthogonal steel beams based on reaction frame columns or by erecting additional columns. The steel beams are then arranged along the edge of the specimen and pressed tightly against it to prevent out-of-plane instability. Occasionally, a relatively simple and low-cost treatment method using steel strands is used. However, both of these methods have significant drawbacks.

[0031] 1. Anti-instability devices are large, costly, and space-consuming: Generally, four orthogonal steel beams are installed, with two beams arranged along the edge of the specimen and close to it. Holes are drilled at specific locations as needed before installation. This is a common anti-instability method, but it is costly. After the specimen is replaced, the anti-instability device may not be usable and new holes need to be drilled. After several drillings, it becomes unusable. Some companies and laboratories have replaced all the steel beams with steel columns with holes to accommodate different test sizes and added friction-reducing components. This makes the device even larger. When the anti-instability device is not in use, laboratory space is limited, or there is no space to place it. In reality, the force used to prevent or limit out-of-plane instability of the specimen does not need to be too large. Using channel steel or crossbeams to limit structural instability is somewhat conservative.

[0032] 2. Anti-instability device depends on environment and surrounding equipment: Since the arrangement of anti-instability device must rely on columns, most easily unstable specimens must be tested in reaction frames. If there is no reaction frame, the test personnel need to set up columns, which further increases the cost and makes the test installation work more complicated.

[0033] 3. The influence of friction on the anti-instability device during the test is difficult to estimate: if the steel clamp is too tight, the data collected from the actuator will be inaccurate; if it is too loose, the anti-instability effect of the device will be poor. Some companies have optimized this point by arranging many rollers between the contact surface of the steel and the specimen to reduce friction. The effect is better, but the cost is higher.

[0034] 4. Installation is complicated and dangerous: For the anti-instability device that is used repeatedly, there are many bolts and bolt holes, and it is necessary to work at height. The column must be firmly and tightly installed with respect to the ground and the column and the steel frame, which is laborious.

[0035] 5. Using steel strands to prevent specimen instability is difficult to operate. Steel strands have a certain degree of elasticity, which can lead to inaccurate measurement data. In addition, as the actuator is loaded, the specimen deforms back and forth, making it difficult to ensure that the specimen does not deviate to one side.

[0036] 6. Using steel strands to prevent specimen instability is highly dangerous. Once a steel strand breaks, it is extremely dangerous. Even if two steel strands are tied together, with one serving as a protective layer and not subjected to stress, although this has some effect, it is still difficult to guarantee safety.

[0037] Based on the above problems, this invention proposes a new anti-instability device with a simple structure, easy installation, low manufacturing cost, and no reliance on peripheral equipment. It is suitable for various types of large-scale structural engineering test specimens and has minimal impact on the stress on the specimens during the test, ensuring the accuracy of the collected data. At the same time, the instability device has high safety, requires no cumbersome high-altitude operations, and will not cause danger due to device breakage.

[0038] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0039] like Figure 1 The diagram shown illustrates a structural design for an anti-instability device suitable for large-scale structural engineering tests, according to an embodiment of the present invention. The device includes:

[0040] A pad assembly 1 is used to support the specimen. There are at least two sets of pad assemblies 1, which are connected to each other by a binding assembly 4.

[0041] Support component 2, one end of which is connected to pad assembly 1, is used to provide lateral restraint force;

[0042] The self-propelled component 3 is connected to the other end of the support component 2. When the specimen shifts, it causes the support component 2 to shift as well. The self-propelled component 3 moves the support point synchronously under the shift of the support component 2.

[0043] The pad assembly 1 includes:

[0044] Follower component, which is attached to the test specimen;

[0045] A horizontal component is connected to the support assembly 2. A following component is movably connected to the horizontal component. When the specimen tilts, the following component rotates relative to the horizontal component to prevent the support assembly 2 from twisting.

[0046] In one embodiment of the present invention, the anti-instability device suitable for large-scale structural engineering tests utilizes a pad assembly 1 to press against the specimen and release torque, ensuring that even if the specimen tilts during the structural test, the pad assembly 1 can always provide lateral constraint force. The support assembly 2 supports the pad assembly 1 and can be arbitrarily spliced ​​according to the height of the specimen. It is simple to use and easy to store. The self-propelled assembly 3 can move the support point synchronously with the specimen, avoiding excessive bending of the specimen which would cause the support assembly 2 to pull on the specimen and result in inaccurate data measurement. The binding assembly 4 is used to connect the pad assembly 1 and the specimens between the pad assemblies 1. It is easy to use, can be extended, and can adapt to specimens of different shapes and sizes. For small specimens, a pair of pad assemblies 1 and support assemblies 2 is sufficient. For specimens with a slightly larger width, multiple pairs of support assemblies 2 can be used and connected to the same self-propelled assembly 3.

[0047] like Figure 2 and Figure 3 As shown, in a preferred embodiment of the present invention, the follower includes:

[0048] The first plate 101 has a pivot pin 104 at its center, and through holes are provided on both sides of the pivot pin 104 to provide space for the rotation of the follower and the horizontal member.

[0049] The second plate 102 is in contact with the specimen, and the second plate 102 has an opening that is connected to the binding assembly 4;

[0050] The intermediate plate 103, located between the first plate 101 and the second plate 102, is used to reduce the friction between the contact surface of the follower and the horizontal member.

[0051] The first plate 101 can be a steel plate with the shaft pin 104 as the center, and its through holes are arc-shaped and distributed in a fan shape. The second plate 102 is the bottom steel plate and is in direct contact with the specimen. The intermediate plate 103 is sandwiched between the first plate 101 and the second plate 102 and is tightly bonded together to effectively protect the intermediate plate 103 and prevent it from cracking or being damaged. Specifically, the intermediate plate 103 can be a polytetrafluoroethylene plate with a very low coefficient of friction. After the horizontal part and the following part are installed and fitted, their contact surfaces can slide freely after contacting the intermediate plate 103.

[0052] like Figure 4 As shown, in another preferred embodiment of the present invention, the horizontal member includes:

[0053] Insert plate 105, the center of the insert plate 105 is provided with a circular hole that cooperates with the shaft pin 104, and the two sides of the circular hole are provided with protrusions that cooperate with the through hole. When the follower is tilted with the test piece, the protrusions slide in the through hole.

[0054] Ear plate 106 is connected to the insert plate 105 and the ear plate 106 is connected to the support assembly 2.

[0055] The protrusions on the insert plate 105 cooperate with the arc-shaped through holes. Specifically, the arc-shaped protrusions are also distributed in a fan shape, with the shaft pin hole as the center. The shaft pin hole cooperates with the shaft pin 104. The arc length of the arc-shaped protrusions is shorter than the arc length of the arc-shaped through holes on the first plate 101. The ear plate 106 is welded to the insert plate 105 and connected to the support assembly 2. The first plate 101, the second plate 102, the intermediate plate 103, and the insert plate 105 can all be set to about 300mm*100mm. The ear plate 106 is set to 70mm in height and 60mm in width. The diameter of the hole on the ear plate 106 is about 36mm. Except for the intermediate plate 103, which is relatively thin, the thickness of each part is set to 10mm.

[0056] In practical use, the follower and the horizontal component are connected together. The shaft pin 104 passes through the shaft pin hole, and the arc-shaped protrusion is inserted into the arc-shaped through hole. The follower always fits tightly against the specimen, moving and tilting with it. The horizontal component is connected to the support assembly 2 and remains horizontal throughout the test. When the follower tilts left or right with the specimen, the arc-shaped protrusion of the horizontal component slides in the arc-shaped through hole of the follower, preventing the support assembly 2 from twisting due to the tilt of the follower. Their operational relationship is as follows: Figure 12 , 13 As shown;

[0057] The torque is released by using the 104 shaft pin, the arc-shaped protrusion, and the arc-shaped through hole, thereby ensuring that the anti-instability device always provides only lateral restraint force.

[0058] like Figures 5 to 7 As shown, in a preferred embodiment of the present invention, the support component 2 includes:

[0059] A connector 201 is provided, and a pin 202 is connected to the connector 201. The two ends of the pin 202 are respectively connected to the pad assembly 1.

[0060] The support end 203 is connected to the connector 201, and the other end of the support end 203 is connected to the support rod 204. The other end of the support rod 204 is connected to the self-propelled component 3.

[0061] The connector 201 is specifically a hollow cylinder with an elongated groove, and the pin 202 is a cylindrical structure with an elongated protrusion. During installation, the connector 201 and the ear plate 106 are placed at the same height. The pin 202 passes through the slot on one side of the ear plate 106, inserts into the connector 201, and finally reaches the other side of the ear plate 106, thus connecting with it. Because the elongated protrusion on the pin 202 penetrates the elongated groove between the connector 201 and the ear plate 106, the connector is completely fixed and cannot be rotated or pulled out, thereby ensuring... For a secure connection, when installing the support rod 204, insert the threaded end into the tail of the support end 203 and then rotate it to complete the connection. The length of the support rod 204 can be selected, specifically 1m, 0.5m, 0.2m, etc. During the test, the number and length of the rods can be selected as needed. The diameter of the pin 202 is set to 36mm and the length to be about 320mm. The inner diameter of the connector 201 is 36mm, the outer diameter is about 50mm, and the length is 100mm. The outer diameter of the support rod 204 is 40mm and the inner diameter is about 30mm.

[0062] Support component 2 adopts a spliced ​​multi-segment special steel pipe. The steel pipes are interlocked and threaded connections are used. The splicing is convenient and the length is adjustable. The interlocking can effectively improve the bending stiffness of the rod, while the threaded connection makes the connection between the rods tighter and prevents loosening.

[0063] When the pin 202 is connected to the ear plate 106, there are many elongated slots evenly distributed on the ear plate 106. The elongated protrusion on the pin 202 is inserted into the elongated slots for fixation, so the support angle can be flexibly adjusted. The support rod 204 is connected to the rotatable walking rod 301, so the installation angle of the device can be adjusted at will.

[0064] like Figure 8 As shown, in a preferred embodiment of the present invention, the self-propelled component 3 includes:

[0065] A base 303, on which a crossbar 302 is mounted;

[0066] The walking rod 301 has one end movably connected to the crossbar 302 and the other end connected to the support rod 204. When the support rod 204 is offset, the walking rod 301 moves autonomously on the crossbar 302.

[0067] One end of the walking rod 301 is threaded and connected to the support rod 204, while the other end is an arched collar connected to the crossbar 302. The base 303 can be assembled. Depending on the structure of the reaction floor used in the test, various forms can be designed, such as dot matrix type, channel type, etc., with corresponding bases. The walking rod 301 moves on the crossbar 302 to achieve the self-propelled function, moves synchronously with the specimen, and does not apply tension to the specimen.

[0068] like Figure 9 As shown, in a preferred embodiment of the present invention, the support end 203 includes a laser lamp 20301 located at the center of the cross-section of the support end 203.

[0069] A laser lamp 20301 is fixed at the inner center of the support end 203. When there is no offset, the light is always at the center of each section of the support rod 204.

[0070] like Figure 9 As shown, in a preferred embodiment of the present invention, the walking pole 301 includes:

[0071] The photosensitive element 30101 corresponds to the laser lamp 20301. The light emitted by the laser lamp 20301 is emitted along the axis of the support rod 204. When the support rod 204 is tilted, the light shines on different positions of the photosensitive element 30101, generating different voltage differences.

[0072] Circuit board 30102 is connected to the photosensitive element 30101, receives different voltage signals fed back by the photosensitive element 30101, and sends instructions to power supply 30103;

[0073] Gear 30104 is connected to power supply 30103. When power supply 30103 receives a command, it drives the walking rod 301 to rotate forward or reverse, thereby driving gear 30104 to move on the serrations of crossbar 302.

[0074] The laser lamp 20301 is located at the center of the cross-section at the bottom of the support end 203. The light beam is emitted along the axis of the tube. Different voltage differences are generated when the light shines on different positions of the photosensitive element 30101. The voltage feedback at the center position is set to 0, the voltage feedback signal at the left position is negative, and the voltage feedback signal at the right position is positive. The circuit board 30102 sends a command to the power supply 30103 according to the different voltage signals fed back by the photosensitive element 30101. The power supply 30103 supplies power to the gear 30104 to achieve rotation. The above components are located at the bottom of the tube of the walking rod 301.

[0075] After the specimen is installed, the laser shines on the center of the photosensitive element 30101. There is no voltage signal input, and the anti-instability device does not move. The laser always shines on the center of the photosensitive element 30101 along the axis of the support rod 204. After the loading starts, the specimen slowly deforms, causing the support rod 204 to shift. The laser landing point is slightly to the left or right. The photosensitive element 30101 generates a voltage signal and submits it to the circuit board 30102. The circuit board 30102 sends a command to the power supply 30103. The power supply 30103 adjusts the positive and negative directions according to the signal to realize the forward and reverse rotation of the gear 30104. The gear 30104 meshes with the sawtooth of the crossbar 302, driving the walking rod 301 to move until the laser shines on the center position again.

[0076] In addition to being able to move passively following the deformation of the specimen, it can also shield the signal of the judgment device and manually adjust the moving speed and direction by directly inputting signals to the power supply from the outside. Its advantage is that even if the actuator loading speed is fast and the specimen deforms rapidly, the anti-instability device can still provide a stable lateral constraint force. When encountering a sudden situation, the test can continue in this way.

[0077] The device for determining whether the support rod 204 is tilted only uses a laser lamp 20301, a photosensitive element 30101, a power supply, wires, and a switch. It has low manufacturing cost, is easy to use, and is easy to disassemble. In addition, a guide rail or tracked crossbar can be used on the base 303 to replace the crossbar 302 to achieve a self-propelled function.

[0078] like Figure 10 As shown, in a preferred embodiment of the present invention, the binding component 4 includes:

[0079] The connecting strap 401 has snap-fit ​​tabs 403 at both ends for connecting the pad assembly 1 and fixing the specimen.

[0080] Adjustment component 402 is installed on the connecting belt 401 and is used to wind up the connecting belt 401 and adjust the length of the connecting belt 401.

[0081] The connecting strap 401 has fine steel strands inside and is wrapped with cloth on the outside, which is both pressure-resistant and wear-resistant, and reduces the thickness of the cloth strap. It is simple and easy to use. The connecting strap 401 passes through the long strip openings on both sides of the second plate 102. The connecting strap 401 has laps 403 at both ends, which can easily achieve binding and unbinding. The adjusting part 402 is a length adjusting part. Its functions are to adjust the length of the binding component and to tighten the binding component, so that the second plate 102 is firmly fixed on the test piece.

[0082] like Figure 11 As shown, in a preferred embodiment of the present invention, the adjusting member 402 includes:

[0083] The outer casing has through slots on both sides, through which the connecting strip 401 passes;

[0084] The first bevel gear 40201 is installed in the housing;

[0085] The second bevel gear 40202 is installed in the housing and continuously meshes with the first bevel gear 40201. A rotating rod 40203 is connected in the second bevel gear 40202 for winding up excess connecting strip 401.

[0086] The buckle 40204 is installed on the housing and connected to the rotating rod 40203 to limit the rotation of the rotating rod 40203.

[0087] The first bevel gear 40201 is the driving gear, and the second bevel gear 40202 is the driven gear. The rotating rod 40203 is welded to the second bevel gear 40202. It rolls up the excess length of the cloth strip. After the rotating rod 40203 rolls up the excess length of the cloth strip, the rotation of the rotating rod 40203 is restricted by the buckle 40204. When it is necessary to adjust the length of the connecting belt 401, a hex wrench is inserted into the hexagonal hole of the first bevel gear 40201 and rotated. The rotation of the first bevel gear 40201 drives the second bevel gear 40202 and the rotating rod 40203 above it to rotate, thereby causing the connecting belt 401 to wrap around the rotating rod 40203, realizing the tightening of the connecting belt 401, and thus making the pad assembly 1 fit tightly against the specimen.

[0088] How to use:

[0089] After the specimen is installed, before the test, place the pad assembly 1 symmetrically on both sides of the specimen of the vertical actuator. Pass the four joints 403 of the two connecting straps 401 through the rectangular holes on the second plate 102 respectively, fix the base 303 on the ground, place the walking rod 301 between the bases 303, and pass the crossbar 302 through the walking rod 301 and the base 303. Connect the support rod 204 to the walking rod 301. When the specimen is high, multiple support rods 204 can be spliced ​​together. Adjust the angle, select a suitable groove on the ear plate 106, connect the pin 202 to the pad assembly 1, turn on the laser light 20301, photosensitive element 30101, circuit board 30102, and power supply 30103 to drive the self-propelled assembly 3 to move automatically to the standard position. The anti-instability device is installed and the test loading can be carried out.

[0090] In actual experiments, specimen instability is often caused by insufficient installation accuracy, uneven material distribution throughout the specimen, or localized defects. Applying a lateral force to the specimen to prevent instability does not require a large value. Therefore, the commonly used method of using multiple steel sections to prevent specimen instability is overly conservative and wasteful of resources. This device is relatively lightweight. The following is a rough calculation and estimation of the reliability of the device structure:

[0091] like Figure 14 As shown, assuming a 3m long steel beam is used as the test model, the steel beam is a common H300mm*150mm*6.5mm*9mm steel. There are defects in the fabrication and installation of the steel beam. There is a torsional angle from the beginning. The stress is shown in the figure below. The error between the fixed loading point and the centroid is 30mm. The reason is that the specimen deviates to this extent, which can be identified by the naked eye and can be manually intervened.

[0092] Assuming the quasi-static test is loaded to a displacement angle of 6%, i.e., the maximum displacement of the actuator pushing and pulling the specimen is 180mm (3000mm * 0.06), the stiffness is calculated using the graphical method, and the maximum value of the actuator load F in the test is predicted:

[0093]

[0094]

[0095]

[0096] in l For Liang Chang, F For actuator load, x The distance between the cross-section and the bottom fixed end. E I is the elastic modulus of the steel section (206 GPa for Q345 steel), and I is the moment of inertia of the section (its value can be found in the specification as 7350 mm). 4 After substituting the values, the calculation is as follows: K =1682.3kN / m, actuator F The maximum value is set at 1682.3 kN / m * 0.18m = 302.814 kN (in reality, material damage during loading will lead to stiffness degradation, and the structure itself will also have a certain torsional resistance, so the calculated value is much larger than the actual value). h The maximum bending moment exerted by the actuator on the steel profile is the distance (30mm) from the centroid of the actuator. M =9.09kN*m. Taking the stress on the steel section as the background, the reliability of the anti-instability device structure with a support rod length of 5m will be calculated below.

[0097] When the actuator load is 303kN, assuming the actuator loading point deviates from the centroid of the steel profile by 30mm, the connecting joint 201 in the support assembly experiences a large shear force, which is:

[0098] ,

[0099]

[0100] in l 1 represents a length of 201, and the calculated shear stress at the cross-section is 11.63 MPa. This value is much smaller than its yield strength, indicating that the section is safe and meets the usage requirements.

[0101] The bending moment is provided by the support rod. When M = 9.09 kN*m, the support rod is considered as a simply supported beam with both ends hinged and a bending moment applied to one end. Its maximum deflection is at a length of 2.5m, and its value is:

[0102]

[0103] In the formula: E , I These are the elastic modulus and moment of inertia of the support rod, respectively. D , d Let be the outer diameter and inner diameter of the rod, respectively. The calculation results show that under bending moment, its deflection is only 0.4 mm. The critical force for its compressive instability is calculated using Euler's formula:

[0104]

[0105] The other parts are subjected to less stress or have more conservative dimensions than the support rod and connecting joint, so they will not be calculated one by one here;

[0106] As can be seen from the above rough calculation results, although the size of the rod and each component in the embodiment of the present invention is small, it can fully meet the usage requirements, provide sufficient support force, and have minimal deformation. The function of controlling the movement of the self-propelled component by using a laser lamp at the top and arranging photosensitive elements at the bottom is also fully achievable.

[0107] The anti-instability device provided in this invention is compact in structure, easy to install, and has low manufacturing and installation costs. After the test, it can be disassembled, effectively saving test space. During use, it occupies a small area and is largely independent of the surrounding environment and equipment. It can be used normally regardless of whether the ground is flat or whether there are reaction frames or columns to provide reaction force. It can effectively constrain the structure without affecting the deformation and stress of the specimen. When the specimen bends left or right, the device moves on its own without generating tension. When the specimen deforms significantly and the deflection is obvious, the pad assembly can rotate, and the device always provides only lateral constraint force, avoiding errors in test data caused by friction and tension. Most procedures can be completed on the ground, thus avoiding most high-altitude work and reducing the workload of bolt tightening and hoisting. The support assembly is made of specially made steel pipe with high rigidity. The self-propelled assembly can adapt well to the displacement caused by specimen deformation and is symmetrically arranged, thus preventing the specimen from falling to one side. It has high safety during both installation and use.

[0108] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An anti-instability device suitable for large-scale structural engineering tests, characterized in that, The device includes: A pad assembly for supporting the specimen, wherein there are at least two sets of pad assemblies connected to each other by a binding assembly; A support assembly, one end of which is connected to the pad assembly, for providing lateral restraint force; The self-propelled component is connected to the other end of the support component. When the specimen shifts, it causes the support component to shift. The self-propelled component moves the support point synchronously under the shift of the support component. The pad assembly includes: Follower component, which is attached to the test specimen; A horizontal component is connected to a support assembly, and a following component is movably connected to the horizontal component. When the specimen tilts, the following component rotates relative to the horizontal component to prevent the support assembly from twisting. The follower includes: The first plate has a pivot pin at its center and through holes on both sides of the pivot pin, which provide space for the rotation of the follower and the horizontal member. The second plate is in contact with the specimen, and the second plate has an opening for connection with the binding assembly; The intermediate plate, located between the first plate and the second plate, is used to reduce the friction between the contact surface of the follower and the horizontal plate. The horizontal component includes: The insert plate has a central hole that engages with the shaft pin, and protrusions on both sides of the central hole that engage with the through hole. When the follower plate tilts with the specimen, the protrusions slide in the through hole. Ear plate, connected to the insert plate, and the ear plate is connected to the support assembly; The support components include: A connector, wherein a pin is connected in the connector, and the two ends of the pin are respectively connected to the pad assembly; The supporting end is connected to the connector, the other end of the supporting end is connected to the support rod, and the other end of the support rod is connected to the self-propelled assembly; The self-propelled component includes: A base on which a crossbar is mounted; A walking pole, one end of which is movably connected to a crossbar, and the other end of which is connected to a support pole; The walking pole includes: A photosensitive element, corresponding to a laser lamp, is located at the center of the cross-section of the support end. The light emitted by the laser lamp is emitted along the axis of the support rod. When the support rod is tilted, the light shines on different positions of the photosensitive element, generating different voltage differences. The circuit board is connected to the photosensitive element, receives different voltage signals fed back by the photosensitive element, and sends commands to the power supply. The gear is connected to the power source. When the power source receives a command, it drives the gear to rotate forward or backward, causing the traveling rod to move along the serrations of the crossbar.

2. The anti-instability device for large-scale structural engineering tests according to claim 1, characterized in that, The bundled components include: A connecting strap, with snap-fit ​​ends for connecting the pad assembly and fixing the specimen; An adjusting element, installed on the connecting belt, is used to wind up the connecting belt and adjust its length.

3. The anti-instability device for large-scale structural engineering tests according to claim 2, characterized in that, The adjusting element includes: The outer casing has through slots on both sides, through which the connecting strap passes; A first bevel gear is installed in the housing; The second bevel gear is installed in the housing and continuously meshes with the first bevel gear. A rotating rod is connected to the second bevel gear for winding up excess connecting strip. A buckle, installed on the housing and connected to the rotating rod, is used to limit the rotation of the rotating rod.

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