Seismic testing device for steel structure connecting joint

Abstract

The present application relates to the technical field of detection device, specifically relates to a kind of steel structure connecting node's anti-seismic testing device.A kind of steel structure connecting node's anti-seismic testing device includes two adjusting mechanisms.Adjusting mechanism includes pivot, eccentric component and adjusting component.Eccentric component includes multiple eccentric wheels.Multiple eccentric wheels are divided into multiple first wheels and multiple second wheels.Two pivots rotate in the same direction, and first wheel or second wheel drives movable platform reciprocating movement by adjusting component.Because the sum of the eccentric force of multiple first wheels on one pivot is equal to the sum of the eccentric force of multiple second wheels, and the eccentric direction of first wheel and second wheel is opposite, it can avoid first wheel and second wheel to make the up and down vibration of pivot.The present application provides a kind of steel structure connecting node's anti-seismic testing device to solve the problem that cam will cause the up and down vibration of cam pivot when using eccentric cam structure in existing anti-seismic test device, thereby affecting anti-seismic test.

Description

Technical Field

[0001] This invention relates to the field of testing device technology, and specifically to a seismic testing device for steel structure connection nodes. Background Technology

[0002] The seismic testing device for steel structure connection nodes is a key piece of equipment used to simulate earthquake effects in a laboratory environment and evaluate the seismic performance of the nodes. Its core function is to test the performance of the nodes under strong earthquakes by accurately applying simulated seismic loads, thus providing a scientific basis for structural safety.

[0003] Steel structures are widely used in modern architecture, especially in high-rise and long-span structures in earthquake-prone areas, due to their high strength, light weight, and good ductility. Numerous earthquake damage investigations (such as the 1994 Northridge earthquake in the United States and the 1995 Hanshin earthquake in Japan) show that damage to steel structures often occurs not in the beams and columns themselves, but rather in the beam-column connection nodes. Failure at these nodes can lead to the collapse of the entire structure. Therefore, connection nodes are critical components for ensuring the overall seismic performance of steel structures; their strength, stiffness, ductility, and energy dissipation capacity under seismic loading directly affect the safety of the structure.

[0004] Traditional testing equipment mainly falls into two categories: electro-hydraulic servo actuation systems and mechanical vibration systems. Electro-hydraulic servo actuation systems achieve vibration through high-power servo actuators, but these systems are expensive and consume a lot of energy. Mechanical vibration systems use centrifugal force generated by the rotation of an eccentric wheel to vibrate the specimen. However, the amplitude (intensity of vibration) of a mechanical vibration system is usually fixed, determined by the eccentricity of the eccentric wheel. Changing the amplitude requires stopping the machine and manually replacing the eccentric wheel with one of different eccentricities, or performing complex mechanical adjustments. This process is very time-consuming and labor-intensive, severely impacting testing efficiency.

[0005] For example, utility model patent CN220708671U provides a structural seismic testing device. This device uses a first bearing to support a threaded rod, a second groove to guide a second fixed block, and a second opening and a second bearing to facilitate the installation and operation of the cam and rotating rod, aiming to solve the problems of existing devices being unable to simulate multiple vibration modes and the specimen not being securely fixed. However, when using an eccentric cam structure, the inherent eccentricity of this device causes the rotating shaft to vibrate up and down. This additional vibration interference will adversely affect the accurate simulation of nodal performance testing under seismic loads. Summary of the Invention

[0006] This invention provides a seismic testing device for steel structure connection nodes to solve the problems of existing seismic testing devices, such as difficulty in amplitude adjustment and the impact on seismic testing caused by the eccentricity of the cam shaft due to eccentricity when using an eccentric cam structure.

[0007] The seismic testing device for steel structure connection nodes of the present invention adopts the following technical solution: A seismic testing device for steel structure connection nodes, used for testing steel structures, includes an installation platform, a movable platform, and two adjustment mechanisms. The movable platform is slidably mounted on the installation platform along a first direction, which is a horizontal direction. The steel structure includes interconnected horizontal and vertical rods, with the horizontal rods fixedly connected to the installation platform. The vertical rods are fixedly connected to the movable platform.

[0008] Two adjustment mechanisms are located on opposite sides of the movable platform along a first direction. Each adjustment mechanism includes a rotating shaft, two eccentric components, and two adjustment components. The rotating shaft is positioned along a second direction and rotatably mounted on the mounting platform. The second direction is horizontal and perpendicular to the first direction.

[0009] Two eccentric components are distributed along a second direction. Each eccentric component includes multiple eccentric wheels distributed along the second direction and eccentrically mounted on a rotating shaft. The eccentricity of the multiple eccentric wheels gradually increases from one end of each eccentric component towards the center of the rotating shaft. The multiple eccentric wheels in each eccentric component are divided into multiple first wheels and multiple second wheels. The eccentric directions of the first wheels and the second wheels are opposite. The sum of the eccentric forces of the multiple first wheels on a rotating shaft is equal to the sum of the eccentric forces of the multiple second wheels.

[0010] During operation, each adjusting component corresponds to one eccentric wheel in an eccentric component. When the two shafts rotate in the same direction, the eccentric wheel in each eccentric component drives the movable platform to reciprocate along the first direction through the adjusting component.

[0011] Furthermore, in the two eccentric components on the same rotating shaft, multiple first wheels correspond one-to-one, and multiple second wheels correspond one-to-one. The eccentricity of two corresponding first wheels is the same, and the eccentricity of two corresponding second wheels is the same. The first wheels with the same eccentricity on the two rotating shafts correspond one-to-one, and the second wheels with the same eccentricity correspond one-to-one.

[0012] Furthermore, each adjustment mechanism includes a bidirectional screw arranged along the second direction, rotatably mounted on the mounting platform. The bidirectional screw has threaded grooves in opposite directions. Each adjustment component includes a slider slidably mounted on the bidirectional screw along the second direction, with each slider corresponding to and threadedly engaging a threaded groove on the bidirectional screw. Each slider abuts against either a first wheel or a second wheel.

[0013] When the bidirectional screw rotates in the forward direction, the two sliders on the same bidirectional screw move closer to each other. When the bidirectional screw rotates in the reverse direction, the two sliders on the same bidirectional screw move further apart.

[0014] Furthermore, each slider has a flat surface and an inclined surface at the end near the eccentric wheel, with the inclined surfaces on the two sliders on the same axis facing opposite directions. When the farthest point of the eccentricity of the first wheel on one axis contacts the corresponding slider, the two sliders on the other axis move away from each other, creating a gap between the closest point of the eccentricity of the first wheel on the other axis and the inclined surface on the corresponding slider, thus reducing friction between the first wheel and the slider.

[0015] Furthermore, the installation platform includes a base and two support columns, both of which are fixed to the ground. The two support columns are vertically positioned on either side of the base along a first direction. The movable platform is slidably mounted on the base along the first direction. A horizontal bar is positioned along the first direction, with its two ends fixedly connected to the two support columns respectively.

[0016] Furthermore, each adjusting mechanism includes at least one transmission component, which comprises a rack and a gear. The rack is fixedly mounted on the mounting platform and is arranged along a first direction. The gear is fixedly mounted on a double-acting screw and is coaxially arranged with the double-acting screw.

[0017] When the center of the movable platform and the center of symmetry of the two adjusting mechanisms are on the same vertical line, the gear and rack disengage. When the center of the movable platform deviates from the center of symmetry of the two adjusting mechanisms, the gear and rack in the adjusting mechanism closest to the movable platform engage.

[0018] When the movable platform moves closer to a rotating shaft, the rack and gear in the adjustment mechanism containing that shaft mesh, causing the gear to rotate in the opposite direction and the double-headed screw to rotate in the opposite direction. When the movable platform moves away from a rotating shaft, the gear in the adjustment mechanism containing that shaft rotates in the forward direction and the double-headed screw rotates in the forward direction.

[0019] Furthermore, each bidirectional screw is fixedly equipped with a handwheel, and rotating the handwheel drives the bidirectional screw to rotate.

[0020] Furthermore, each adjustment mechanism includes at least one drive assembly, which includes a motor, a first transmission pulley, and a belt. The motor is fixedly mounted on the base. The first transmission pulley is fixedly mounted on the rotating shaft and is coaxial with the rotating shaft. The belt connects the output shaft of the motor to the first transmission pulley.

[0021] Furthermore, each eccentric wheel includes an inner wheel, an outer wheel, and multiple balls. The inner wheel is fixedly connected to the shaft and is eccentrically positioned relative to the shaft. The outer wheel is rotatably positioned outside the inner wheel and is coaxial with the inner wheel. Multiple balls are positioned between the inner and outer wheels.

[0022] Furthermore, a guide rail along the first direction is fixedly installed on the base, and a slide groove along the first direction is opened on the lower side of the movable platform, with the guide rail and the slide groove slidingly engaged.

[0023] The beneficial effects of this invention are as follows: The seismic testing device for steel structure connection nodes of this invention, through an adjustable mechanism, allows for different distances the moving platform along a first direction to be propelled by the multiple eccentric wheels in each eccentric component due to their varying eccentricities. Based on the required vibration amplitude from the rotation of the eccentric wheels during each test, a corresponding first or second wheel is selected to correspond with the adjusting component. By using multiple eccentric wheels, the amplitude of the seismic testing device for steel structure connection nodes becomes adjustable, resulting in higher working efficiency.

[0024] Two rotating shafts rotate in the same direction. The first or second wheel in each eccentric assembly drives the movable platform to reciprocate along a primary direction via an adjusting component. The movable platform then moves the vertical rod, thereby testing the steel structure.

[0025] Because the sum of the eccentric forces of the multiple first wheels on a rotating shaft is equal to the sum of the eccentric forces of the multiple second wheels, and the eccentric directions of the first and second wheels are opposite, the eccentric forces exerted by the multiple first wheels on the shaft during rotation are equal in magnitude and opposite in direction, thus canceling each other out. This prevents the shaft from vibrating vertically due to the first and second wheels deviating from the shaft axis, which could affect the seismic testing of the steel structure. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a structural schematic diagram of a seismic testing device for a steel structure connection node provided in an embodiment of the present invention;

[0028] Figure 2 A side view of a seismic testing device for a steel structure connection node provided in an embodiment of the present invention;

[0029] Figure 3 for Figure 2 Sectional view along the middle AA direction;

[0030] Figure 4 for Figure 3 Enlarged view of point C in the middle;

[0031] Figure 5 for Figure 2 Sectional view along the BB direction;

[0032] Figure 6 for Figure 5 Enlarged view of point D in the middle;

[0033] Figure 7 This is a top view of a seismic testing device for a steel structure connection node provided in an embodiment of the present invention;

[0034] Figure 8 for Figure 7 Enlarged view at point E in the middle;

[0035] Figure 9 A partial structural schematic diagram of a seismic testing device for a steel structure connection node provided in an embodiment of the present invention;

[0036] Figure 10 A schematic diagram of the base of a seismic testing device for a steel structure connection node provided in an embodiment of the present invention;

[0037] Figure 11 A partial structural schematic diagram of the adjustment mechanism of a seismic testing device for a steel structure connection node provided in an embodiment of the present invention;

[0038] Figure 12 This is a schematic diagram of another part of the adjustment mechanism of a seismic testing device for a steel structure connection node provided in an embodiment of the present invention.

[0039] In the diagram: 100, base; 101, support column; 102, belt; 103, motor; 105, rack; 106, guide rail; 201, movable platform; 202, slider; 2021, plane; 2022, inclined plane; 203, double-acting screw; 204, gear; 205, handwheel; 301, rotating shaft; 302, first wheel; 3021, ball bearing; 303, second wheel; 304, first transmission wheel; 401, horizontal bar; 402, vertical bar. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Reference Figures 1 to 12As shown in the figure, an embodiment of the present invention provides a seismic testing device for steel structure connection nodes, used for testing steel structures, including an installation platform, a movable platform 201, and two adjustment mechanisms. The movable platform 201 is slidably disposed on the installation platform along a first direction, which is the horizontal direction.

[0042] The steel structure includes interconnected horizontal bars 401 and vertical bars 402. The horizontal bars 401 are fixedly connected to the mounting platform and are arranged along a first direction. The vertical bars 402 are vertically arranged, with their upper ends fixedly connected to the horizontal bars 401 and their lower ends fixedly connected to the movable platform 201. The center of the vertical bars 402 and the center of the movable platform 201 are on the same vertical line.

[0043] Two adjustment mechanisms are located on opposite sides of the movable platform 201 along a first direction. Each adjustment mechanism includes a rotating shaft 301, two eccentric components, and two adjustment components. The rotating shaft 301 is arranged along a second direction and rotatably mounted on the mounting platform. The second direction is horizontal and perpendicular to the first direction.

[0044] Two eccentric components are distributed along a second direction. Each eccentric component includes multiple eccentric wheels distributed along the second direction and eccentrically mounted on a rotating shaft 301. The eccentricity of the multiple eccentric wheels gradually increases from one end of each eccentric component towards the center of the rotating shaft 301. The multiple eccentric wheels in each eccentric component are divided into multiple first wheels 302 and multiple second wheels 303. The eccentric directions of the first wheels 302 and the second wheels 303 are opposite. The multiple first wheels 302 are sequentially distributed along the axial direction of the rotating shaft 301, and the multiple second wheels 303 are sequentially distributed along the axial direction of the rotating shaft 301. Preferably, the multiple first wheels 302 and the multiple second wheels 303 are alternately arranged.

[0045] The sum of the eccentric forces of the multiple first wheels 302 on a rotating shaft 301 is equal to the sum of the eccentric forces of the multiple second wheels 303. The eccentric force of the first wheel 302 is the product of its eccentricity and its mass. The eccentric force of the second wheel 303 is the product of its eccentricity and its mass. The eccentricity is the distance between the axis of the eccentric wheel and the axis of the rotating shaft 301.

[0046] During operation, each adjusting component corresponds to either a first wheel 302 or a second wheel 303 in an eccentric component. When the two rotating shafts 301 rotate in the same direction, the first wheel 302 or the second wheel 303 in each eccentric component drives the movable platform 201 to reciprocate along the first direction through the adjusting component.

[0047] First, the horizontal bar 401 is fixedly connected to the mounting platform, and the vertical bar 402 is fixedly connected to the middle of the movable platform 201. In the initial state, the axis of the first wheel 302 or the second wheel 303 is on the same straight line as the axis of the rotating shaft 301, and this straight line is set vertically.

[0048] Because the eccentricity of the multiple eccentric wheels in each eccentric component is different, the distance by which the multiple eccentric wheels push the movable platform 201 to move along the first direction varies through the adjustment component. Based on the amplitude of the vibration caused by the rotation of the eccentric wheels required for each test, a corresponding first wheel 302 or second wheel 303 is selected to correspond with the adjustment component. For example, when one adjustment component corresponds to the first wheel 302, then all other adjustment components also correspond to the first wheel 302, and all of them are first wheels 302 with the same eccentricity. When one adjustment component corresponds to the second wheel 303, then all other adjustment components also correspond to the second wheel 303, and all of them are second wheels 303 with the same eccentricity.

[0049] Two rotating shafts 301 rotate in the same direction. The first wheel 302 or the second wheel 303 in each eccentric assembly drives the movable platform 201 to reciprocate along the first direction through the adjusting assembly. The movable platform 201 drives the vertical rod 402 to move, thereby testing the steel structure.

[0050] Since the sum of the eccentric forces of the multiple first wheels 302 on a rotating shaft 301 is equal to the sum of the eccentric forces of the multiple second wheels 303, and the eccentric directions of the first wheels 302 and the second wheels 303 are opposite, the eccentric forces exerted by the multiple first wheels 302 on the rotating shaft 301 during rotation are equal in magnitude and opposite in direction, thus canceling each other out. This prevents the first wheels 302 and the second wheels 303 from deviating from the axis of the rotating shaft 301, which could cause vertical vibrations of the rotating shaft 301 during rotation and thus affect the seismic testing of the steel structure.

[0051] In this embodiment, multiple first wheels 302 and multiple second wheels 303 in the two eccentric components on the same rotating shaft 301 correspond one-to-one. The eccentricity of two corresponding first wheels 302 is the same, and the eccentricity of two corresponding second wheels 303 is the same. The first wheels 302 with the same eccentricity on the two rotating shafts 301 correspond one-to-one, and the second wheels 303 with the same eccentricity correspond one-to-one.

[0052] In this embodiment, each adjustment mechanism further includes a bidirectional screw 203 arranged along a second direction, which is rotatably mounted on the mounting platform. Each bidirectional screw 203 is located between a rotating shaft 301 and the movable platform 201. The bidirectional screw 203 has threaded grooves with opposite directions.

[0053] Each adjusting component includes a slider 202, which is slidably mounted on a bidirectional screw 203 along a second direction, and each slider 202 corresponds to and is threadedly engaged with a threaded groove on the bidirectional screw 203. Each slider 202 abuts against a first wheel 302 or a second wheel 303. All sliders 202 abut against the same wheel type (first wheel 302 or second wheel 303) and eccentricity.

[0054] When the bidirectional screw 203 rotates in the forward direction, the two sliders 202 on the same bidirectional screw 203 move closer to each other. When the bidirectional screw 203 rotates in the reverse direction, the two sliders 202 on the same bidirectional screw 203 move further apart from each other.

[0055] In this embodiment, each slider 202 has a flat surface 2021 and an inclined surface 2022 on the end near the eccentric wheel. The inclined surfaces 2022 on the two sliders 202 on the same rotating shaft 301 are oriented in opposite directions. The flat surface 2021 and the inclined surface 2022 are distributed sequentially along the direction of gradually approaching the adjacent slider 202. Along the direction of gradually approaching the adjacent slider 202, the inclined surface 2022 gradually approaches the movable platform 201. The flat surface 2021 and the slider 202 abut against each other, increasing stability.

[0056] When the farthest point of the eccentricity of the first wheel 302 on one of the rotating shafts 301 comes into contact with the corresponding slider 202, the two sliders 202 on the other rotating shaft 301 move away from each other, so that there is a gap between the closest point of the eccentricity of the first wheel 302 on the other rotating shaft 301 and the inclined surface 2022 on the corresponding slider 202, and the gap is the largest, which is used to reduce the friction between the first wheel 302 and the slider 202.

[0057] In this embodiment, the installation platform includes a base 100 and two support columns 101, both of which are fixed to the ground. The two support columns 101 are vertically arranged on both sides of the base 100 along a first direction. The movable platform 201 is slidably mounted on the base 100 along the first direction. A horizontal bar 401 is arranged along the first direction, and its two ends are fixedly connected to the two support columns 101 respectively. The material of the horizontal bar 401 can be concrete or steel.

[0058] In this embodiment, each adjusting mechanism includes at least one transmission component, which includes a rack 105 and a gear 204. The rack 105 is fixedly mounted on the mounting platform and is arranged along a first direction. The gear 204 is fixedly mounted on the bidirectional screw 203 and is coaxially arranged with the bidirectional screw 203.

[0059] When the center of the movable platform 201 and the center of symmetry of the two adjusting mechanisms are on the same vertical line, the gear 204 and rack 105 disengage. When the center of the movable platform 201 deviates from the center of symmetry of the two adjusting mechanisms, the gear 204 and rack 105 in the adjusting mechanism that the movable platform 201 is closest to engage.

[0060] When the movable platform 201 moves closer to a rotating shaft 301, the rack 105 and gear 204 in the adjustment mechanism containing the rotating shaft 301 mesh, causing the gear 204 to rotate in the opposite direction, the double-sided screw 203 to rotate in the opposite direction, and the two sliders 202 on the double-sided screw 203 to move away from each other. When the movable platform 201 moves away from a rotating shaft 301, the gear 204 in the adjustment mechanism containing the rotating shaft 301 rotates in the forward direction, the double-sided screw 203 rotates in the forward direction, and the two sliders 202 on the double-sided screw 203 move closer to each other.

[0061] In this embodiment, a handwheel 205 is fixedly provided on each bidirectional screw 203, and rotating the handwheel 205 is used to drive the bidirectional screw 203 to rotate.

[0062] In this embodiment, each adjustment mechanism includes at least one drive component, which includes a motor 103, a first transmission wheel 304, and a belt 102. The motor 103 is fixedly mounted on the base 100. The first transmission wheel 304 is fixedly mounted on the rotating shaft 301 and is coaxial with the rotating shaft 301. The belt 102 connects the output shaft of the motor 103 to the first transmission wheel 304. The motor 103 drives the first transmission wheel 304 to rotate through a first transmission, thereby driving the rotating shaft 301 to rotate.

[0063] In this embodiment, each eccentric wheel includes an inner wheel, an outer wheel, and a plurality of balls 3021. The inner wheel is fixedly connected to the shaft 301 and is eccentrically positioned relative to the shaft 301. The outer wheel is rotatably positioned outside the inner wheel and is coaxial with the inner wheel. The plurality of balls 3021 are disposed between the inner wheel and the outer wheel. The inner wheel and the outer wheel can rotate relative to each other, thereby reducing friction between the eccentric wheel and the slider 202.

[0064] In this embodiment, a guide rail 106 along the first direction is fixedly provided on the base 100, and a sliding groove along the first direction is provided on the lower side of the movable platform 201. The guide rail 106 and the sliding groove are slidably engaged so that the movable platform 201 can only move along the first direction.

[0065] Working process: First, fix both ends of the horizontal rod 401 to the two support columns 101 respectively. Then fix the lower end of the vertical rod 402 to the middle of the movable platform 201. In the initial state, the center of the movable platform 201 and the center of symmetry of the two adjustment mechanisms are on the same vertical line, which is the initial position of the movable platform 201. The rack 105 and gear 204 are disengaged. In the initial state, the axis of the first wheel 302 or the second wheel 303 is on the same straight line as the axis of the rotating shaft 301, and this straight line is set vertically. The farthest point of eccentricity of the first wheel 302 is higher than the farthest point of eccentricity of the second wheel 303. The farthest point of eccentricity of the first wheel 302 is the farthest point of the first wheel 302 from the center of the rotating shaft 301.

[0066] Because the eccentricity of the multiple eccentric wheels in each eccentric assembly is different, the distances by which the eccentric wheels push the slider 202 and the movable platform 201 to move along the first direction are different. Based on the amplitude of the vibration caused by the rotation of the eccentric wheels required for each test, the corresponding first wheel 302 or second wheel 303 is selected to abut against the slider 202. Manually rotating the handwheel 205 drives the bidirectional screw 203 to rotate, which in turn moves the two sliders 202, ensuring that the eccentricity of the first wheel 302 abutting against all sliders 202 is the same.

[0067] Then, the motor 103 is started. The motor 103 drives the first transmission wheel 304 to rotate through the first transmission, which in turn drives the rotating shaft 301 to rotate. The two rotating shafts 301 rotate in the same direction, and the rotating shafts 301 drive the first wheel 302 and the second wheel 303 to rotate.

[0068] The movable platform 201 has a first side and a second side on either side along the first direction. When the farthest point of the eccentricity of the first wheel 302 on the first side deflects toward the movable platform 201, the slider 202 on the first side pushes the movable platform 201 to move along the direction from the first side to the second side. At this time, the farthest point of the eccentricity of the second wheel 303 on the second side deflects away from the movable platform 201 to make room for the movable platform 201 to move.

[0069] As the movable platform 201 moves from the first side to the second side, the gear 204 and rack 105 on the second side mesh, driving the bidirectional screw 203 on the second side to rotate in the opposite direction. The bidirectional screw 203 causes the two sliders 202 on the second side to move away from each other. Since the sliders 202 are provided with inclined surfaces 2022, the distance between the inclined surfaces 2022 of the sliders 202 and the first wheel 302 gradually increases after the two sliders 202 move away from each other.

[0070] When the farthest point of the eccentricity of the first wheel 302 on the first side contacts the corresponding slider 202, the movable platform 201 moves to the first limit position along the direction from the first side to the second side. At this time, there is a gap between the inclined surface 2022 on the slider 202 on the second side and the closest point of eccentricity of the first wheel 302 on the second side, and the gap is at its maximum. This prevents interference between the slider 202 on the second side and the first wheel 302 on the second side when the movable platform 201 moves closer to the first wheel 302 on the second side, and at the same time reduces the friction between the first wheel 302 and the slider 202 when rotating, thereby extending the service life of the first wheel 302. The first limit position is the farthest distance that the first wheel 302 can push the movable platform 201 to move, that is, the moving distance is the eccentricity of the first wheel 302.

[0071] Then, the first wheel 302 continues to rotate, and the farthest point of the eccentricity of the first wheel 302 on the first side deflects away from the moving platform 201. At this time, the first wheel 302 on the first side no longer pushes the slider 202. The farthest point of the eccentricity of the first wheel 302 on the second side deflects closer to the moving platform 201.

[0072] As the moving platform 201 moves along the first direction, it simultaneously moves the lower end of the vertical rod 402, causing the vertical rod 402 to gradually tilt. When the first wheel 302 on the first side no longer pushes the slider 202, and there is a gap between the slider 202 on the second side and the first wheel 302, and the moving platform 201 is not pushed by any of the first wheels 302, the vertical rod 402 will experience three situations:

[0073] In the first scenario, the vertical rod 402 undergoes elastic deformation but not plastic deformation. After tilting, the vertical rod 402 returns to its original position under its own elastic force. The vertical rod 402 then moves the movable platform 201 along the direction from the second side to the first side and returns to its original position until the vertical rod 402 is completely vertical. At this point, the vertical rod 402 moves the movable platform 201 to its initial position.

[0074] During the movement of the platform 201 from the first extreme position to the initial position, the gear 204 and rack 105 on the second side cooperate with each other, causing the bidirectional screw 203 on the second side to rotate in the forward direction. The forward rotation of the bidirectional screw 203 drives the two sliders 202 to move closer to each other until the plane 2021 of the sliders 202 abuts against the first wheel 302.

[0075] At this point, the farthest point of the eccentricity of the first wheel 302 on the second side continues to rotate towards the moving platform 201. The first wheel 302 on the second side pushes the moving platform 201 along the direction from the second side to the first side to the second limit position via the slider 202. The second limit position is the farthest distance that the first wheel 302 can push the moving platform 201 to move.

[0076] In the second scenario: the vertical rod 402 undergoes partial plastic deformation, enabling the movable platform 201 to move a certain distance from the second side to the first side. The rack 105 and gear 204 on the second side mesh, causing the bidirectional screw 203 to rotate in the forward direction, and the two sliders 202 on the second side move closer to each other. When the inclined surface 2022 of the slider 202 contacts the first wheel 302, under the action of the vertical rod 402 driving the movable platform 201 to move and the rotation of the first wheel 302 pushing the movable platform 201 to move, the planes 2021 of the two sliders 202 abut against the first wheel 302, and the movable platform 201 moves from the first extreme position to the initial position.

[0077] The third scenario: The vertical rod 402 undergoes plastic deformation and cannot move the movable platform 201. In this case, the machine must be stopped and the steel structure removed. Then, turn the handwheel 205, and the rack 105 and gear 204 will mesh. The gear 204 will rotate and move the movable platform 201 back to its initial position.

[0078] Two rotating shafts 301 rotate continuously, thereby driving the movable platform 201 to reciprocate along the first direction via the slider 202. Since the sum of the eccentric forces of the multiple first wheels 302 on one rotating shaft 301 is equal to the sum of the eccentric forces of the multiple second wheels 303, and the eccentric directions of the first wheels 302 and the second wheels 303 are opposite, during the rotation of the rotating shaft 301, the eccentric forces of the multiple first wheels 302 on the rotating shaft 301 and the eccentric forces of the multiple second wheels 303 on the rotating shaft 301 are equal in magnitude and opposite in direction, thus canceling each other out. This prevents the rotating shaft 301 from vibrating vertically due to the first wheels 302 and the second wheels 303 deviating from the axis of the rotating shaft 301, which could affect the seismic testing of the steel structure.

[0079] After one test is completed, the movable platform 201 is moved to the initial position, the rack 105 and gear 204 disengage, and then the handwheel 205 is turned to adjust the eccentric wheel contacted by the slider 202 to adjust the amplitude of vibration, thus enabling the next test. By setting multiple eccentric wheels, the amplitude of the seismic testing device for steel structure connection nodes is adjustable, resulting in higher working efficiency.

[0080] 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, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A seismic testing device for steel structure connection nodes, used for testing steel structures, characterized in that: It includes an installation platform, a movable platform, and two adjustment mechanisms; the movable platform is slidably mounted on the installation platform along a first direction, which is horizontal; the steel structure includes interconnected horizontal and vertical rods, with the horizontal rods fixedly connected to the installation platform; the vertical rods are fixedly connected to the movable platform. Two adjustment mechanisms are located on opposite sides of the movable platform along a first direction; each adjustment mechanism includes a rotating shaft, two eccentric components, and two adjustment components; the rotating shaft is arranged along a second direction and is rotatably mounted on the mounting platform; the second direction is horizontal and perpendicular to the first direction; Two eccentric components are distributed along a second direction. Each eccentric component includes multiple eccentric wheels distributed along the second direction and eccentrically mounted on a rotating shaft. The eccentricity of the multiple eccentric wheels gradually increases from one end of each eccentric component towards the center of the rotating shaft. The multiple eccentric wheels in each eccentric component are divided into multiple first wheels and multiple second wheels. The eccentric directions of the first wheels and the second wheels are opposite. The sum of the eccentric forces of the multiple first wheels on a rotating shaft is equal to the sum of the eccentric forces of the multiple second wheels. During operation, each adjusting component corresponds to one eccentric wheel in an eccentric component; when the two shafts rotate in the same direction, the eccentric wheel in each eccentric component drives the movable platform to reciprocate along the first direction through the adjusting component; Multiple first wheels in two eccentric components on the same rotating shaft correspond one-to-one, and multiple second wheels correspond one-to-one. The eccentricity of two corresponding first wheels is the same, and the eccentricity of two corresponding second wheels is the same. The first wheels with the same eccentricity on two rotating shafts correspond one-to-one, and the second wheels with the same eccentricity correspond one-to-one. Each adjustment mechanism also includes a bidirectional screw arranged along the second direction, which is rotatably mounted on the mounting platform; the bidirectional screw has threaded grooves in opposite directions; each adjustment component includes a slider, which is slidably mounted on the bidirectional screw along the second direction, and each slider corresponds to and is threadedly engaged with a threaded groove on the bidirectional screw; each slider abuts against a first wheel or a second wheel; When the bidirectional screw rotates in the forward direction, the two sliders on the same bidirectional screw move closer to each other; when the bidirectional screw rotates in the reverse direction, the two sliders on the same bidirectional screw move further apart.

2. The seismic testing device for steel structure connection nodes according to claim 1, characterized in that: Each slider has a flat surface and an inclined surface at one end near the eccentric wheel. The inclined surfaces on the two sliders on the same axis are in opposite directions. When the farthest point of the eccentricity of the first wheel on one axis comes into contact with the corresponding slider, the two sliders on the other axis move away from each other, so that there is a gap between the closest point of the eccentricity of the first wheel on the other axis and the inclined surface on the corresponding slider, which is used to reduce the friction between the first wheel and the slider.

3. The seismic testing device for steel structure connection nodes according to claim 1, characterized in that: The installation platform includes a base and two pillars, both of which are fixed to the ground. The two pillars are vertically arranged on both sides of the base along a first direction. The movable platform is slidably arranged on the base along the first direction. A horizontal bar is arranged along the first direction, and its two ends are fixedly connected to the two pillars respectively.

4. The seismic testing device for steel structure connection nodes according to claim 3, characterized in that: Each adjustment mechanism includes at least one transmission component, which includes a rack and a gear; the rack is fixedly mounted on the mounting platform and is arranged along a first direction; the gear is fixedly mounted on a double-acting screw and is coaxial with the double-acting screw. When the center of the movable platform and the center of symmetry of the two adjustment mechanisms are on the same vertical line, the gear and rack disengage; when the center of the movable platform deviates from the center of symmetry of the two adjustment mechanisms, the gear and rack in the adjustment mechanism that the movable platform is closest to engage. When the moving platform moves closer to a rotating shaft, the rack and gear in the adjustment mechanism of that rotating shaft mesh, causing the gear to rotate in the opposite direction and the bidirectional screw to rotate in the opposite direction; when the moving platform moves away from a rotating shaft, the gear in the adjustment mechanism of that rotating shaft rotates in the forward direction and the bidirectional screw rotates in the forward direction.

5. The seismic testing device for steel structure connection nodes according to claim 1, characterized in that: Each bidirectional screw is fixedly equipped with a handwheel, and turning the handwheel drives the bidirectional screw to rotate.

6. The seismic testing device for steel structure connection nodes according to claim 3, characterized in that: Each adjustment mechanism includes at least one drive component, which includes a motor, a first transmission wheel, and a belt; the motor is fixedly mounted on the base; the first transmission wheel is fixedly mounted on the rotating shaft and is coaxial with the rotating shaft; the belt connects the output shaft of the motor to the first transmission wheel.

7. The seismic testing device for steel structure connection nodes according to claim 1, characterized in that: Each eccentric wheel includes an inner wheel, an outer wheel, and multiple balls; the inner wheel is fixedly connected to the shaft and is eccentrically positioned with respect to the shaft; the outer wheel is rotatably positioned outside the inner wheel and is coaxial with the inner wheel; the multiple balls are positioned between the inner wheel and the outer wheel.

8. The seismic testing device for steel structure connection nodes according to claim 3, characterized in that: A guide rail along the first direction is fixedly installed on the base, and a slide groove along the first direction is opened on the lower side of the movable platform. The guide rail and the slide groove slide together.

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