Adjustable friction enhancement type lug plate beam column joint structure

Abstract

The invention provides an adjustable friction enhancement type lug plate beam column joint structure, and relates to the technical field of building components. The structure comprises a stand column and a cross beam, and connecting plates are arranged at the upper and lower column ends of the stand column; the cross beam is H-shaped steel, an inner lug plate and an outer lug plate are symmetrically arranged on the two sides of a web of the cross beam, and the outer lug plate is connected with the web through a long round hole and a fastener. The contact face of the inner lug plate and the outer lug plate is provided with a complementary corrugated structure which comprises a first corrugated face and a second corrugated face which are arranged in a staggered mode, and a controllable friction gap is formed. An n-shaped plate is arranged on a web of the cross beam, and a first flexible tensioning piece and a second flexible tensioning piece are arranged in a cavity of the n-shaped plate in a penetrating mode and connected with the stand columns on the two sides respectively. Through gradual friction energy consumption of the corrugated structure and dynamic constraint and self-resetting functions of the flexible tensioning piece, efficient energy dissipation and structure recovery of the joint under dynamic load are achieved, and the problems that traditional joint rigid connection is prone to brittle failure and insufficient in energy dissipation are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of building components, and in particular relates to an adjustable friction-enhanced ear plate beam-column node structure. Background Art

[0002] Beam-column joints are key connection points in building structures and are widely used in high-rise buildings, bridges, industrial plants and other scenarios. Their performance directly affects the safety and durability of the structure under dynamic loads such as earthquakes, wind loads or mechanical vibrations. Traditional beam-column joints mostly use rigid welding or bolted connections to transfer loads through material stiffness, but this type of design is prone to brittle failure when subjected to sudden dynamic loads and cannot effectively dissipate energy. With the complexity of building functions and the frequent occurrence of extreme environmental events, higher requirements are placed on the seismic energy dissipation, self-reset capability and long-term reliability of node structures.

[0003] Traditional beam-column node technology mainly relies on rigid connection structure or simple friction interface design, which has significant defects. Rigid connection achieves node rigidity through high-strength bolts or welding, but lacks energy dissipation mechanism, which leads to brittle fracture under earthquakes or strong winds, and cannot adapt to small displacements caused by thermal expansion and contraction. Although the planar friction interface design can absorb part of the energy through the sliding friction plate, the contact surface is prone to stick-slip phenomenon, resulting in unstable vibration response, and the friction coefficient is constant and cannot be dynamically adjusted. It is easy to fail due to local wear during long-term reciprocating sliding. In addition, the stiffness adjustment range of a single constraint system is limited, it is easy to break when overloaded, and lacks self-reset function. The accumulation of residual deformation will reduce the stability of the structure.

[0004] Considering that metal components are prone to fatigue fracture under cyclic loads, and composite interfaces are prone to stiffness attenuation due to creep or bonding failure, some structures rely on mechanical devices to achieve displacement compensation, but the installation accuracy is high, and long-term use leads to functional degradation due to component wear or lubrication failure, which significantly increases maintenance costs; some structures also have the problem of rigidity recovery dependence, and cannot actively drive the nodes back to their original positions, and the accumulation of residual deformation accelerates structural damage. Summary of the invention

[0005] The present invention overcomes the shortcomings of the prior art and provides an adjustable friction-enhanced ear plate beam-column node structure.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: an adjustable friction-enhanced ear plate beam-column node structure, including a column and a beam.

[0007] The upright column comprises an upper column and a lower column, and ends of the upper column and the lower column are both provided with connecting plates extending outwards.

[0008] The cross beam is an H-shaped steel, including a web and a flange, and the flange is connected to a connecting plate.

[0009] The inner ear plate and the outer ear plate are symmetrically arranged on both sides of the web. One side of the inner ear plate is fixed to the outer surface of the column. The outer ear plate is connected to the web by fasteners. An oblong hole is opened on the outer ear plate, and a round hole is opened on the inner ear plate. The fastener passes through the oblong hole, the web and the round hole.

[0010] The contact surfaces of the inner ear plate and the outer ear plate are provided with matching corrugated structures, which include a first corrugated surface provided on the inner ear plate and a second corrugated surface provided on the outer ear plate, with a gap between the first corrugated surface and the second corrugated surface.

[0011] In a preferred embodiment of the present invention, the corrugated profiles of the first corrugated surface and the second corrugated surface are periodic continuous curves, and the crests of the first corrugated surface correspond to the troughs of the second corrugated surface, and the troughs of the first corrugated surface correspond to the crests of the second corrugated surface.

[0012] In a preferred embodiment of the present invention, the crest height of the corrugated structure is 2-5 mm, the wavelength is 15-30 mm, and the gap width is 1-2 mm, which is evenly distributed along the extension direction of the corrugation.

[0013] In a preferred embodiment of the present invention, at least one ""-shaped plate is provided on the web of the crossbeam, the ""-shaped plate is a U-shaped cross-section structure, the opening faces the web and is fixed to the web, and a cavity is formed inside. A flexible tensioning member is inserted into the cavity, and the two ends of the flexible tensioning member are respectively fixedly connected to the connecting plates of the two side columns.

[0014] In a preferred embodiment of the present invention, the flexible tensioning member includes a first flexible tensioning member, and both ends are fixed to the connecting plate by a first hinged anchor. The first flexible tensioning member is made of ultra-high molecular weight polyethylene fiber or aramid fiber through a multi-strand braiding process to form a rope-like structure, with a diameter of 10-20 mm, a breaking elongation of 3%-5%, and a slack margin of 5%-8% is applied during installation. The slack margin refers to the percentage by which the installation length of the first flexible tensioning member exceeds the theoretical straight-line distance between the anchor points at both ends.

[0015] In a preferred embodiment of the present invention, the flexible tensioning member includes a second flexible tensioning member, both ends of which are fixed to the connecting plate by second hinged anchors. The second flexible tensioning member uses 1860MPa grade low relaxation steel strand or shape memory alloy strand, with a diameter of 8-15mm, and a pre-strain rate of 0.8%-1.2% is applied during installation. The pre-strain rate is the ratio of the tension elongation to the initial length.

[0016] In a preferred embodiment of the present invention, the extending direction of the oblong hole of the outer ear plate is parallel to the axial direction of the crossbeam, and the length of the oblong hole is 1.5-2 times the diameter of the fastener screw.

[0017] In a preferred embodiment of the present invention, the fastener is a high-strength bolt assembly, including a bolt rod passing through an oblong hole, a web and a circular hole, a main nut located on the inner side of the inner ear plate on the bolt rod, a gasket close to the outer surface of the outer ear plate, a disc spring washer sleeved on the bolt rod and close to the gasket, and a locking nut located on the bolt rod and compressing the disc spring washer.

[0018] In a preferred embodiment of the present invention, both ends of the oblong hole of the external ear plate are provided with stop blocks, which are rectangular steel blocks with a thickness greater than that of the external ear plate, and are welded and fixed to the surface of the external ear plate and located at the ends of the oblong hole.

[0019] In a preferred embodiment of the present invention, the contact surface between the inner ear plate and the outer ear plate is covered with a wear-resistant coating having a thickness of 0.05-0.15 mm and being a tungsten carbide or diamond-like coating.

[0020] The present invention solves the defects existing in the background technology and has the following beneficial effects: (1) The present invention provides a complementary corrugated structure of the inner ear plate and the outer ear plate, and includes a first flexible tensioner with a slack margin and a second flexible tensioner with a prestrain rate. On the one hand, the friction energy dissipation is adjustable by controlling the corrugation geometric parameters and the gap, and the load transfer path is optimized by combining the oblong hole sliding mechanism. On the other hand, the slack margin of the first flexible tensioner and the prestrain rate of the second flexible tensioner are used to realize the staged control of plastic energy dissipation and shape memory reset, thereby improving the seismic toughness and post-disaster recoverability while ensuring the stiffness of the node, and solving the problems of brittle failure of traditional beam-column nodes under dynamic loads, inability to adjust energy dissipation and self-reset.

[0021] (2) A corrugated structure with staggered crests and troughs is arranged on the contact surface between the inner ear plate and the outer ear plate. The outer ear plate is connected to the web of the crossbeam through an oblong hole in a sliding manner, and the corrugation gaps are evenly distributed. The crests and troughs of the corrugated structure are staggered to form a progressive contact. In the initial stage of sliding, only the top of the crest contacts to produce low friction resistance, ensuring the rigidity of the node under small deformation; as the load increases, the side walls of the corrugations gradually participate in the contact, the friction area increases exponentially, and the friction coefficient gradually increases; when the deformation is large, the contact at the root of the corrugations induces local plastic deformation, further consuming energy. The oblong hole allows the outer ear plate to slide in a directional manner, and the maximum slip amount is controlled by the limit block to avoid overload failure. The traditional planar friction interface is prone to stick-slip vibration, and the contact area cannot be adjusted. The present invention is triggered in stages through friction energy consumption to avoid brittle failure caused by stress concentration, and at the same time compensates for thermal deformation through gaps.

[0022] (3) The first flexible tensioner controls the initial extension space through the relaxation margin, and the second flexible tensioner presets the shape memory driving force through the pre-strain rate. The two are arranged in the cavity of the cross-beam web, forming a phased energy dissipation and reset path. In the elastic deformation stage, the relaxation margin of the first tensioner allows it to bend naturally without participating in the force. At this time, the pre-strain rate of the second tensioner puts it in a high tension state, and the initial slip of the crossbeam is suppressed by the pre-tightening force; when the node displacement exceeds the threshold, the first tensioner is gradually straightened by tension, and the fiber molecular chain slips and dissipates energy, while the shape memory alloy of the second tensioner triggers the martensitic phase transformation due to deformation and stores elastic strain energy; after unloading, the second tensioner recovers the austenitic state through temperature recovery, releases the stored energy to drive reset, and at the same time, the elastic retraction of the first tensioner assists in completing the recovery of the remaining displacement. When traditional nodes use a single steel strand or a viscous damper, the energy dissipation and reset functions restrict each other. However, the present invention activates plastic energy dissipation and shape memory reset in stages during the deformation process, which not only avoids premature stiffness degradation but also ensures rapid reset after unloading.

[0023] (4) The height of the corrugation peak determines the friction contact pressure distribution and indirectly controls the activation threshold of the first tensioner. When the peak height is low, the friction energy consumption is delayed, and the plastic energy consumption needs to be triggered in advance by reducing the relaxation margin of the first tensioner. The corrugation wavelength and the pre-strain rate of the second tensioner jointly regulate the reset response speed. The long wavelength prolongs the single friction stroke and provides a sufficient time window for the phase transformation of the shape memory alloy, while the high pre-strain rate accelerates the generation of the phase transformation driving force. The two work together to shorten the reset time. In the early stage of corrugation sliding, the pre-tightening force of the second tensioner maintains the node stiffness; when the corrugation enters the high friction stage, the first tensioner is subjected to tensile energy consumption; in the plastic deformation stage of the corrugation root, the phase change driving force of the second tensioner is synchronously triggered. When the node is subjected to dynamic load, the corrugated structure adjusts the friction energy consumption intensity through geometric parameters, and the flexible tensioner controls the reset ability through material properties, and the two form a closed-loop feedback mechanism. This mechanism not only avoids the stress concentration caused by rigid connection of traditional nodes, but also overcomes the functional limitations of a single energy-consuming element. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work. Figure 1 It is a front view of an adjustable friction-enhanced lug-plate beam-column node structure; Figure 2 It is an axonometric view of an adjustable friction-enhanced lug-plate beam-column joint structure; Figure 3 It is a structural diagram of the lower column; Figure 4 It is a structural diagram of the beam; Figure 5 It is a structural schematic diagram of the corrugated structure; Figure 6 It is a schematic diagram of the structure of the fastener; In the figure: 1. column; 2. crossbeam; 3. inner ear plate; 4. outer ear plate; 5. fastener; 6. letter plate; 7. flexible tensioner; 8. corrugated structure; 11. upper column; 12. lower column; 13. connecting plate; 21. web plate; 22. wing plate; 31. round hole; 41. oblong hole; 42. limit block; 511. main nut; 512. gasket; 513. disc spring washer; 514. anti-loosening nut; 71. first flexible tensioner; 72. first hinged anchor; 73. second flexible tensioner; 74. second hinged anchor; 81. first corrugated surface; 82. second corrugated surface. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0027] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of the present application. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the invention, unless otherwise specified, "multiple" means two or more.

[0028] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood by specific circumstances.

[0029] Example structure: like Figure 1-6 As shown, an adjustable friction enhanced ear plate beam-column node structure includes a column 1 and a cross beam 2. The column 1 includes an upper column 11 and a lower column 12, and the ends of the upper column 11 and the lower column 12 are both provided with a connecting plate 13 extending outward; the cross beam 2 is an H-shaped steel, including a web 21 and a wing plate 22, and the wing plate 22 is connected to the connecting plate 13.

[0030] An inner ear plate 3 and an outer ear plate 4 are symmetrically arranged on both sides of the web 21; one side of the inner ear plate 3 is fixed to the outer surface of the column 1; the outer ear plate 4 is connected to the web 21 through a fastener 5; an oblong hole 41 is opened on the outer ear plate 4, and a round hole 31 is opened on the inner ear plate 3, and the fastener 5 passes through the oblong hole 41, the web 21 and the round hole 31; The contact surfaces between the inner ear plate 3 and the outer ear plate 4 are provided with matching corrugated structures 8; the corrugated structure 8 includes a first corrugated surface 81 provided on the inner ear plate 3 and a second corrugated surface 82 provided on the outer ear plate 4, and there is a gap between the first corrugated surface 81 and the second corrugated surface 82.

[0031] Traditional beam-column joints are prone to brittle failure when subjected to dynamic loads, and cannot effectively adjust the friction energy dissipation characteristics. The above exemplary structure, on the one hand, fixes the inner ear plate 3 to the column 1, and the outer ear plate 4 is slidably connected to the web 21 through the oblong hole 41; on the other hand, complementary corrugations are set on the contact surfaces of the inner ear plate 3 and the outer ear plate 4, and the friction contact area is controlled by the gap to form an adjustable friction interface.

[0032] Specifically, the column 1 at the node is symmetrically connected to the left and right side beams 2, the inner ear plates 3 on the two side beams 2 are respectively welded and fixed to the two side surfaces of the column 1, and the outer ear plates 4 cover the inner ear plates 3 on both sides and the middle column 1 area. When one side of the beam is loaded, the outer ear plate 4 transfers part of the load to the other side through the middle rigid connection to achieve load redistribution; the corrugated structures 8 on both sides slide independently, and the rigid middle section of the outer ear plate 4 coordinates the deformation to avoid unilateral overload. More specifically, when the node is subjected to static load or small amplitude dynamic load, the top of the wave crest of the corrugated structure 8 is slightly in contact, and the friction surface transmits shear force through static friction. At this time, the node stiffness is close to the traditional rigid connection, ensuring the stability of the structure in conventional use. The existence of the gap avoids stress concentration caused by hard contact, while allowing small thermal deformation compensation. When the external load exceeds the static friction threshold, the outer ear plate 4 begins to slide along the oblong hole 41. The crests and troughs of the first corrugated surface 81 and the second corrugated surface 82 alternately engage and separate in this process, forming a periodic friction resistance. During the sliding process, the slope of the wave crest sidewall guides the contact pressure to be evenly distributed, avoiding aggravation of local wear. Under the action of reciprocating load, the change in the sliding speed of the outer ear plate 4 causes an inertial impact at the moment of detachment of the corrugated surface. When the wave crest detaches, the vacuum effect formed briefly between the contact surfaces further absorbs energy. At the same time, the root of the corrugation undergoes a slight plastic deformation due to stress concentration, and the additional energy is dissipated through material yielding. Through the above-mentioned composite energy dissipation method, the problem of stress concentration caused by rigid connection at the beam-column node under dynamic load is effectively reduced.

[0033] like Figure 5 As shown, the corrugated profiles of the first corrugated surface 81 and the second corrugated surface 82 are periodic continuous curves, and the crest of the first corrugated surface 81 corresponds to the trough of the second corrugated surface 82, and the trough of the first corrugated surface 81 corresponds to the crest of the second corrugated surface 82. The crest height of the corrugated structure 8 is 2-5 mm, the wavelength is 15-30 mm, and the gap width is 1-2 mm, which is evenly distributed along the extension direction of the corrugation.

[0034] The flat friction interface is prone to stick-slip phenomenon, resulting in uncontrollable vibration response. By staggered arrangement of crests and troughs, progressive contact is formed, and uniform gaps are maintained along the sliding direction to avoid local jamming, so that the load response is roughly divided into three stages: in the first stage, only the top of the crest is in contact, the contact pressure is elliptical, the maximum pressure is located at the center of the crest, and the friction coefficient is stable at 0.15-0.18. In the second stage, the corrugated sidewalls gradually participate in the contact, the contact area increases exponentially, the contact pressure peak migrates toward the trough direction, and the friction coefficient rises to 0.25-0.30. In the third stage, the root of the corrugation enters the contact state and the contact area reaches the maximum value. At this time, the friction coefficient surges to 0.35-0.40 due to plastic deformation, and the microcracks at the root of the corrugation expand to further absorb energy. At the same time, a closed cavity is formed in the trough area, and the internal air compression produces a damping effect.

[0035] like Figure 4 As shown, at least one ""-shaped plate 6 is provided on the web 21 of the cross beam 2. The ""-shaped plate 6 is a U-shaped cross-section structure, with an opening facing the web 21 and fixed to the web 21, and a cavity is formed inside. A flexible tensioning member 7 is passed through the cavity, and both ends of the flexible tensioning member 7 are respectively fixedly connected to the connecting plates 13 of the two side columns 1. The flexible tensioning member 7 includes a first flexible tensioning member 71 and a second flexible tensioning member 73.

[0036] The two ends of the first flexible tensioner 71 are respectively fixed to the connecting plates 13 on both sides by the first hinged anchor 72; the length of the first flexible tensioner 71 is greater than the straight-line distance between the two anchor points, forming a slack margin. Specifically, the first flexible tensioner 71 is made of ultra-high molecular weight polyethylene fiber or aramid fiber through a multi-strand weaving process to form a rope-like structure with a diameter of 10-20mm and a breaking elongation of 3%-5%. A slack margin of 5%-8% is applied during installation. Among them, the slack margin refers to the percentage by which the installation length of the first flexible tensioner 71 exceeds the theoretical straight-line distance between the two end anchor points, and the non-pre-tightened slack state is achieved by the natural bending of the rope body in the cavity of the cross plate 6.

[0037] The two ends of the second flexible tensioner 73 are respectively fixed to the connecting plates 13 on both sides by the second hinged anchor 74; the second flexible tensioner 73 is applied with a preset preload. Specifically, the second flexible tensioner 73 uses 1860MPa grade low relaxation steel strand or shape memory alloy strand with a diameter of 8-15mm. The steel strand is coated with epoxy resin for corrosion protection, and the austenite finish temperature of the shape memory alloy strand is 25-40℃; a pre-strain rate of 0.8%-1.2% is applied during installation, and the pre-tightening force value is 20%-30% of the node design load to suppress the initial slippage of the beam 2. Among them, the pre-strain rate is the ratio of the tension elongation to the initial length; when unloading, the steel strand is reset by elastic recovery, and the shape memory alloy strand is reset by shape memory effect.

[0038] In a specific embodiment, the first flexible tensioner 71 is made of ultra-high molecular weight polyethylene fiber using an 8-strand braiding process, with a diameter of 12mm, a relaxation margin of 6%, and a breaking load of ≥85kN; the second flexible tensioner 73 uses a nickel-titanium shape memory alloy strand with a diameter of 10mm, a prestrain of 1.0%, an austenite finish temperature of 30°C, and a preload of 45kN. In the elastic deformation stage, the first flexible tensioner 71 remains in a relaxed state, and the fiber is naturally bent; the second flexible tensioner 73 provides basic constraints through the initial preload and bears 5%-10% of the node load. In the plastic deformation stage, when the node displacement exceeds the threshold of 10-15mm, the first flexible tensioner 71 is stretched and gradually straightened and bears 30%-50% shear force, and the breaking strain is controlled at 4%-6%; the nickel-titanium shape memory alloy strand of the second flexible tensioner 73 undergoes a martensitic phase transformation, generating a 6%-8% recoverable strain, while maintaining an initial preload of 60%-70%. In the self-reset stage, when unloading, the nickel-titanium shape memory alloy strands of the second flexible tensioner 73 are heated by electricity or the ambient temperature rises to above the austenite finish temperature, generating a recovery stress of 300-400 MPa, and the driving node is reset to the initial position within 30-60 seconds; the polyethylene fiber of the first flexible tensioner 71 relies on the elastic retraction of the molecular chain to assist in completing the last 5%-10% of the reset stroke; after resetting, the flexible tensioner 7 can withstand subsequent cyclic loads.

[0039] like Figure 4 As shown, the extending direction of the oblong hole 41 of the outer ear plate 4 is parallel to the axial direction of the crossbeam 2 , and the length of the oblong hole 41 is 1.5-2 times the diameter of the screw of the fastener 5 .

[0040] like Figure 6 As shown, the fastener 5 is a high-strength bolt assembly, including a bolt rod passing through the oblong hole 41, the web 21 and the circular hole 31, a main nut 511 located on the inner side of the inner ear plate 3 on the bolt rod, a gasket 512 close to the outer surface of the outer ear plate 4, a disc spring washer 513 sleeved on the bolt rod and close to the gasket 512, and a locking nut 514 located on the bolt rod and compressing the disc spring washer 513.

[0041] Conventional fasteners are prone to progressive loosening under complex vibration spectra and cannot compensate for the loss of preload force caused by material creep. The right-handed main nut and the left-handed lock nut cooperate in reverse to provide basic clamping force, and the disc spring washer 513 maintains dynamic preload. On the one hand, the left-handed thread of the lock nut 514 and the right-handed thread of the main nut 511 form a rotational interlock. The vibration energy is converted into additional tightening torque of the lock nut to achieve a dynamic self-tightening effect. On the other hand, the elastic deformation of the disc spring washer 513 compensates for the creep relaxation of the bolt and maintains the preload force.

[0042] like Figure 2As shown, both ends of the oblong hole 41 of the outer ear plate 4 are provided with a stopper 42; the stopper 42 is a rectangular steel block, the thickness of which is greater than the thickness of the outer ear plate 4, and the stopper 42 is welded and fixed to the surface of the outer ear plate 4, and is located at the end of the oblong hole 41. When the slippage of the outer ear plate 4 reaches the end of the oblong hole 41, the stopper 42 is in rigid contact with the bolt rod, and the load is directly transmitted to the column 1 through the inner ear plate 3. The thickened design of the stopper 42 ensures that it will not fail under high impact loads, providing ultimate safety protection for the structure.

[0043] The contact surface between the inner ear plate 3 and the outer ear plate 4 is covered with a wear-resistant coating; the thickness of the wear-resistant coating is 0.05-0.15 mm, and it is a tungsten carbide or diamond-like coating.

[0044] Example 1

[0045] An adjustable friction-enhanced ear plate beam-column node structure specifically comprises the following components: The column 1 is a box-section column with a cross-sectional size of 400 mm×400 mm, and includes an upper column 11 and a lower column 12 fixed by welding. The ends of the upper column 11 and the lower column 12 are both welded with a connecting plate 13 with a thickness of 12 mm.

[0046] The cross beam 2 is an H-shaped steel, including a flange 22 of 200 mm×12 mm and a web 21 of 300 mm×8 mm. The flange 22 is connected to the connecting plate 13 by a high-strength bolt group.

[0047] The inner ear plate 3 is a NM450 wear-resistant steel plate with a thickness of 10 mm, is welded to the outer surface of the column 1, and is provided with 6 circular holes 31.

[0048] The outer ear plate 4 is a NM450 wear-resistant steel plate with a thickness of 10 mm, and is slidably connected to the web plate 21 through 12 oblong holes 41 with a length of 30 mm.

[0049] The corrugated structure 8 includes a first corrugated surface 81 and a second corrugated surface 82 arranged on the contact surface between the inner ear plate 3 and the outer ear plate 4. The first corrugated surface 81 and the second corrugated surface 82 are arranged in a staggered manner with crests and troughs, a crest height of 2 mm, a wavelength of 15 mm, a gap width of less than 2 mm, and a tungsten carbide coating with a thickness of 0.1 mm is sprayed on the surface.

[0050] The cross plate 6 is a U-shaped cross-section steel plate with a thickness of 8 mm and a height of 150 mm. The opening faces the web 21 and is fixed to the middle of the web 21 by a high-strength bolt group.

[0051] The flexible tensioning member 7 includes a first flexible tensioning member 71 and a second flexible tensioning member 73. The first flexible tensioning member 71 is an 8-strand braided ultra-high molecular weight polyethylene fiber rope with a diameter of 12 mm and a slack margin of 5%, and is connected to the connecting plates 13 on both sides through a first hinge anchor 72. The second flexible tensioning member 73 is a nickel-titanium shape memory alloy strand with a diameter of 10 mm, a pre-strain rate of 0.8%, an austenite finish temperature of 30°C, and a pre-tightening force of 36 kN, and is connected to the connecting plates 13 on both sides through a second hinge anchor 74.

[0052] The fastener 5 includes a bolt rod passing through the oblong hole 41, the web 21 and the circular hole 31, a main nut 511 located on the inner side of the inner ear plate 3 on the bolt rod, a gasket 512 close to the outer surface of the outer ear plate 4, a disc spring washer 513 sleeved on the bolt rod and close to the gasket 512, and a locking nut 514 located on the bolt rod and compressing the disc spring washer 513.

[0053] The limiting block 42 is a rectangular steel block welded to the end of the oblong hole 41 .

[0054] Example 2

[0055] Different from Example 1, in this embodiment, the peak height of the corrugated structure 8 is 3.5 mm, and the wavelength is 22.5 mm; the relaxation margin of the first flexible tensioning member 71 is 6.5%; the pre-strain rate of the second flexible tensioning member 73 is 1.0%, and the pre-tightening force is 45 kN.

[0056] Example 3

[0057] Different from Example 1, in this embodiment, the peak height of the corrugated structure 8 is 5 mm, and the wavelength is 30 mm; the relaxation margin of the first flexible tensioning member 71 is 8%; the pre-strain rate of the second flexible tensioning member 73 is 1.2%, and the pre-tightening force is 54 kN.

[0058] Example 4

[0059] Different from the embodiment 1, the peak height of the corrugated structure 8 in this embodiment is 3.5 mm and the wavelength is 15 mm.

[0060] Example 5

[0061] Different from the embodiment 1, the peak height of the corrugated structure 8 in this embodiment is 3.5 mm and the wavelength is 30 mm.

[0062] Example 6

[0063] Different from the embodiment 1, the peak height of the corrugated structure 8 in this embodiment is 2 mm, and the wavelength is 22.5 mm.

[0064] Example 7

[0065] Different from the first embodiment, the peak height of the corrugated structure 8 in this embodiment is 5 mm and the wavelength is 22.5 mm.

[0066] Example 8

[0067] Different from the first embodiment, in this embodiment, the relaxation margin of the first flexible tensioning member 71 is 8%; the pre-strain rate of the second flexible tensioning member 73 is 1.2%, and the pre-tightening force is 54 kN.

[0068] Comparative Example 1 Different from the first embodiment, the external ear plate 4 and the flexible tensioning member 7 are not provided in this comparative example.

[0069] Experimental Example 1 Test pieces were made based on the node structures provided in Examples 1-8 and Comparative Example 1, and the test piece variation parameters based on different Examples and Comparative Examples were shown in the following table: Table 1 Specimen comparison table

[0070] The loading equipment in this experimental example uses an MTS hydraulic servo loading system (range ±500kN, stroke ±150mm), with a reaction frame and fixture system. The column 1 of the specimen is anchored to the rigid base of the laboratory through anchor bolts, and the free end of the beam 2 is connected to the MTS actuator through a universal joint. The relaxation margin of the first flexible tensioner 71 is controlled by the calibration length, and the prestrain rate of the second flexible tensioner 73 is controlled by the hydraulic tensioning device, and strain gauges are installed. The loading procedure of the loading equipment includes preloading, static stage, reciprocating loading and destruction stage. Among them, the preloading is cyclically loaded with ±5kN for 3 times to eliminate the assembly gap and calibrate the sensor; the static stage is unidirectionally loaded to 50kN at a rate of 2mm / min; the reciprocating loading is displacement controlled, with a sine wave of 0.5Hz and an amplitude of ±50mm, for 10 cycles, and the load, displacement and strain parameters are collected; the destruction stage is loaded at a rate of 5kN / s until the bearing capacity drops to 80% of the peak value.

[0071] The experimental method refers to JGJ / T 101-2015 "Code for Seismic Test of Buildings", calculates the ratio of friction and plastic deformation energy consumption to the total input energy, reflects the synergistic energy consumption efficiency, and is recorded as the composite energy consumption coefficient η (%); refers to ISO 16670:2003 "Test Method for Seismic Nodes of Structures", calculates the proportion of residual displacement after unloading, measures the self-resetting ability, and is recorded as the residual displacement rate δ (%); refers to ASTM E2126-11 "Structural Stiffness Test Method", calculates the load-displacement slope in the elastic stage, reflects the normal use stiffness, and is the initial stiffness K (kN / mm); refers to EN 12512:2001 "Steel Node Cyclic Test Code", calculates the critical load for the node to enter plastic deformation, determines the energy consumption start threshold, and is recorded as the yield load Fy (kN); refer to ISO 12106:2017 "Metallic Materials Fatigue Test Methods", calculate the maximum lateral bearing capacity of the node, reflect the safety reserve, and record it as the ultimate bearing capacity F u (kN); refer to ASTM G115-10 "Friction Coefficient Measurement Standard", calculate the contact surface dynamic friction coefficient, determine the friction energy efficiency, recorded as friction coefficient μ, and obtain the experimental results as shown in the following table: Table 2 Key parameter data table

[0072] The experimental data show that the composite energy dissipation coefficient η shows a trend of first increasing and then decreasing with the increase of the peak height (η of Example 1→Example 2→Example 7 groups are 24.7%, 38.2%, and 36.7%, respectively), indicating that a too high peak (5 mm) will lead to uneven distribution of contact pressure, offsetting the friction efficiency gain; the residual displacement rate δ is negatively correlated with the pre-strain rate (0.8% pre-strain rate of Example 1 group corresponds to δ=45.2%, and 1.2% pre-strain rate of Example 8 group corresponds to δ=19.8%), proving that high pre-strain rate improves the reset ability by strengthening the shape memory effect; the ultimate bearing capacity is higher in the long wavelength (30 mm) group (Example 5 group F u =238.1kN) than the short wavelength (15mm) group (Example 4 Group F u =231.4kN) is 2.9% higher because the compression damping of the trough cavity delays the stress concentration.

[0073] In Example 2, the peak height is 3.5 mm, the wavelength is 22.5 mm, the relaxation allowance is 6.5%, and the pre-strain rate is 1.0%. The results are η=38.2% (highest), δ=18.3% (lowest), and F u=245.6kN (highest), μ=0.31 (second highest), with the best comprehensive performance. This is because, on the one hand, the 3.5mm wave crest only contacts the top of the wave crest at the initial stage of sliding (displacement <10mm), and the friction coefficient is stable at 0.15-0.18. At this time, the polyethylene fiber relaxation margin of 6.5% allows the web 21 to deform freely, avoiding premature triggering of plastic energy consumption; the 22.5mm wavelength matches the 0.5Hz loading frequency, so that the wave crest detachment period (about 0.22 seconds) is synchronized with the phase change response time of the nickel-titanium strand (0.2-0.3 seconds), maximizing the compression damping effect of the trough cavity; on the other hand, the 6.5% relaxation margin ensures that the polyethylene fiber is gradually straightened when the displacement is >15mm, and bears 30%-40% of the shear force, and its molecular chain sliding energy consumption complements the corrugation friction; the 1.0% pre-strain rate causes the nickel-titanium strand to transform from austenite to martensite when the displacement is >20mm, generating 300-400MPa recovery stress, driving the node to reset. Furthermore, the progressive contact of the 3.5 mm wave crest delays the triggering of plastic deformation, which buys more phase change response time for the 1.0% prestrain rate stranded wire, forming a sequential synergistic chain of friction energy dissipation, plastic deformation, and finally shape memory reset.

[0074] In Example 1, the peak height is 2 mm, the wavelength is 15 mm, the relaxation allowance is 5%, and the pre-strain rate is 0.8%. The results are η=24.7% (lowest), δ=45.2% (highest), F u =185.3kN (minimum), μ=0.18 (minimum), and the performance is degraded overall. This is because the low wave peak of 2mm causes the friction contact area to reach saturation at a displacement of 8mm (contact pressure peak 6.2MPa), and the subsequent load cannot be dissipated through friction, but instead causes local buckling of the web; the short wavelength of 15mm makes the wave peak detachment frequency as high as 0.67Hz, which exceeds the phase change response limit of nickel-titanium stranded wire (0.5Hz), and the compression damping of the trough cavity is not fully formed. In addition, the low relaxation margin of 5% limits the elongation of polyethylene fiber, and its elongation at break is only 3.8%. It breaks at a displacement of 10mm and loses its plastic energy dissipation effect; the low pre-strain rate of 0.8% makes the driving force of the phase change of nickel-titanium stranded wire insufficient, and the residual friction resistance cannot be overcome after unloading, resulting in δ as high as 45.2%. The low wave peak of 2mm requires a higher relaxation margin (≥7%) to extend the time window for the fiber to participate in energy dissipation, but the 5% relaxation margin of Example 1 group aggravates the premature breakage of the fiber and causes failure.

[0075] The above is based on the ideal embodiment of the present invention. Through the above description, relevant personnel can make various changes and modifications without departing from the technical concept of the present invention. The technical scope of the present invention is not limited to the content in the specification, and the technical scope must be determined according to the scope of the claims.

Claims

1. An adjustable friction-enhanced ear plate beam-column node structure, comprising a column (1) and a beam (2), characterized in that: The upright column (1) comprises an upper column (11) and a lower column (12), and ends of the upper column (11) and the lower column (12) are both provided with connecting plates (13) extending outwards; The cross beam (2) is an H-shaped steel, comprising a web (21) and a flange (22), wherein the flange (22) is connected to the connecting plate (13); An inner ear plate (3) and an outer ear plate (4) are symmetrically arranged on both sides of the web (21); one side of the inner ear plate (3) is fixed to the outer surface of the column (1); the outer ear plate (4) is connected to the web (21) via a fastener (5); an oblong hole (41) is formed on the outer ear plate (4), a round hole (31) is formed on the inner ear plate (3), and the fastener (5) passes through the oblong hole (41), the web (21) and the round hole (31); The inner ear plate (3) and the outer ear plate (4) are provided with mutually matching corrugated structures (8) on their opposing contact surfaces; the corrugated structure (8) comprises a first corrugated surface (81) provided on the inner ear plate (3) and a second corrugated surface (82) provided on the outer ear plate (4); a gap is provided between the first corrugated surface (81) and the second corrugated surface (82).

2. The adjustable friction-enhanced lug-plate beam-column node structure according to claim 1, characterized in that: The corrugated profiles of the first corrugated surface (81) and the second corrugated surface (82) are periodic continuous curves, and the crests of the first corrugated surface (81) correspond to the troughs of the second corrugated surface (82), and the troughs of the first corrugated surface (81) correspond to the crests of the second corrugated surface (82).

3. The adjustable friction-enhanced lug-plate beam-column node structure according to claim 2, characterized in that: The crest height of the corrugated structure (8) is 2-5 mm, and the wavelength is 15-30 mm; the gap width is 1-2 mm, and is evenly distributed along the extension direction of the corrugation.

4. The adjustable friction-enhanced lug-plate beam-column node structure according to claim 1, characterized in that: At least one ""-shaped plate" (6) is arranged on the web (21) of the crossbeam (2); the ""-shaped plate" (6) is a U-shaped cross-section structure, with an opening facing the web (21) and fixed to the web (21), forming a cavity inside; a flexible tensioning member (7) is inserted into the cavity, and two ends of the flexible tensioning member (7) are respectively fixedly connected to the connecting plates (13) of the columns (1) on both sides.

5. The adjustable friction-enhanced lug-plate beam-column node structure according to claim 4, characterized in that: The flexible tensioning member (7) comprises a first flexible tensioning member (71), both ends of which are fixed to the connecting plate (13) by first hinged anchors (72); the first flexible tensioning member (71) is made of ultra-high molecular weight polyethylene fiber or aramid fiber through a multi-strand braiding process to form a rope-like structure, with a diameter of 10-20 mm and a breaking elongation of 3%-5%, and a slack margin of 5%-8% is applied during installation; the slack margin refers to the percentage by which the installation length of the first flexible tensioning member (71) exceeds the theoretical straight-line distance between the anchor points at both ends.

6. The adjustable friction-enhanced lug-plate beam-column node structure according to claim 4, characterized in that: The flexible tensioning member (7) comprises a second flexible tensioning member (73), both ends of which are fixed to the connecting plate (13) via second hinged anchors (74); the second flexible tensioning member (73) is made of 1860 MPa grade low relaxation steel strand or shape memory alloy strand with a diameter of 8-15 mm, and a pre-strain rate of 0.8%-1.2% is applied during installation; the pre-strain rate is the ratio of the tensioning elongation to the initial length.

7. The adjustable friction-enhanced lug-plate beam-column node structure according to claim 1, characterized in that: The extending direction of the oblong hole (41) of the outer ear plate (4) is parallel to the axial direction of the crossbeam (2), and the length of the oblong hole (41) is 1.5 to 2 times the diameter of the screw of the fastener (5).

8. The adjustable friction-enhanced lug-plate beam-column node structure according to claim 1, characterized in that: The fastener (5) is a high-strength bolt assembly, comprising a bolt rod passing through the oblong hole (41), the web (21) and the circular hole (31), a main nut (511) located on the inner side of the inner ear plate (3) on the bolt rod, a gasket (512) in close contact with the outer surface of the outer ear plate (4), a disc spring washer (513) sleeved on the bolt rod and in close contact with the gasket (512), and a locking nut (514) located on the bolt rod and compressing the disc spring washer (513).

9. The adjustable friction-enhanced lug-plate beam-column node structure according to claim 1, characterized in that: Limit blocks (42) are provided at both ends of the oblong hole (41) of the external ear plate (4); the limit blocks (42) are rectangular steel blocks, the thickness of which is greater than the thickness of the external ear plate (4); the limit blocks (42) are welded and fixed to the surface of the external ear plate (4), and are located at the ends of the oblong hole (41).

10. The adjustable friction-enhanced lug-plate beam-column node structure according to claim 1, characterized in that: The contact surface between the inner ear plate (3) and the outer ear plate (4) is covered with a wear-resistant coating; the wear-resistant coating has a thickness of 0.05-0.15 mm and is a tungsten carbide or diamond-like coating.

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