An adjustable friction-enhanced gusset plate beam-column joint structure

Abstract

The present invention provides an adjustable friction-enhanced gusset plate beam-column joint structure, which relates to the technical field of building components. The structure includes a column and a beam. Connecting plates are provided at the upper and lower ends of the column. The beam is an H-shaped steel, and inner gusset plates and outer gusset plates are symmetrically arranged on both sides of its web. The outer gusset plates are connected to the web through oblong holes and fasteners. The contact surfaces of the inner gusset plates and the outer gusset plates are provided with complementary corrugated structures, including a first corrugated surface and a second corrugated surface arranged alternately, forming a controllable friction gap. A channel-shaped plate is arranged on the web of the beam, and a first flexible tension member and a second flexible tension member are respectively arranged in the cavity of the channel-shaped plate and connected to the columns on both sides. Through the progressive friction energy dissipation of the corrugated structure and the dynamic constraint and self-resetting functions of the flexible tension members, the present invention realizes the efficient energy dissipation and structural restoration of the joint under dynamic loads, and solves the problems of easy brittle failure and insufficient energy dissipation of the traditional rigid connection of joints.

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 deficiencies of the prior art and provides an adjustable friction-enhanced ear plate beam-column node structure.

[0006] In order 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, which includes a bolt rod passing through the oblong hole, the web and the round hole, a main nut located inside the inner ear plate on the bolt rod, a gasket closely attached to the outer surface of the outer ear plate, a disc spring washer sleeved on the bolt rod and closely attached to the gasket, and a locknut located on the bolt rod and compressing the disc spring washer.

[0018] In a preferred embodiment of the present invention, limit blocks are provided at both ends of the oblong hole of the outer ear plate. The limit blocks are rectangular steel blocks with a thickness greater than that of the outer ear plate. The limit blocks are welded and fixed to the surface of the outer ear plate and are located at the end 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. The thickness of the wear-resistant coating is 0.05 - 0.15 mm, and it is a tungsten carbide or diamond-like carbon coating.

[0020] The present invention solves the defects existing in the background technology and has the following beneficial effects:

[0021] (1) By setting the complementary corrugated structure of the inner ear plate and the outer ear plate and including a first flexible tension member with a relaxation margin and a second flexible tension member with a pre-strain rate, the present invention, on the one hand, realizes the adjustable friction energy dissipation through the control of corrugation geometric parameters and gaps, and optimizes the load transfer path by combining the oblong hole sliding mechanism; on the other hand, through the relaxation margin of the first flexible tension member and the pre-strain rate of the second flexible tension member, it realizes the staged control of plastic energy dissipation and shape memory reset, thereby improving the seismic toughness and post-disaster recoverability while ensuring the node stiffness, and solving the problems of easy brittle failure, inability to adjust energy dissipation and self-reset of traditional beam-column joints under dynamic loads.

[0022] (2) The contact surface between the inner ear plate and the outer ear plate is provided with a corrugated structure with alternating wave crests and wave troughs. The outer ear plate is slidably connected to the beam web through an oblong hole, and the corrugation gaps are evenly distributed. The alternating arrangement of the wave crests and wave troughs of the corrugated structure forms a progressive contact. At the initial stage of sliding, only the top of the wave crest contacts to generate a low frictional resistance, ensuring the rigidity of the node under small deformations; as the load increases, the side walls of the corrugations gradually participate in the contact, the frictional area increases exponentially, and the friction coefficient gradually increases; when large deformations occur, the contact at the root of the corrugation causes local plastic deformation, further dissipating energy. The oblong hole allows the outer ear plate to slide in a specific direction, and the maximum sliding amount is controlled by the limit block to avoid overloading and failure. The traditional planar friction interface is prone to stick-slip vibration and cannot adjust the contact area, while the present invention avoids brittle failure caused by stress concentration through the staged triggering of friction energy dissipation, and compensates for thermal deformation through gaps at the same time.

[0023] (3) The first flexible tension member controls the initial extension space through the slack margin, and the second flexible tension member presets the shape memory driving force through the pre-strain rate. The two are arranged in the cavity of the channel-shaped plate on the web of the cross beam, forming a staged energy dissipation and reset path. In the elastic deformation stage, the slack margin of the first tension member allows it to bend naturally without participating in the force. At this time, the pre-strain rate of the second tension member keeps it in a high-tension state, and the initial slip of the cross beam is suppressed through the pre-tightening force. When the joint displacement exceeds the threshold, the first tension member is gradually straightened under tension, and the fiber molecular chains slip to dissipate energy, while the shape memory alloy of the second tension member triggers the martensitic transformation due to deformation and stores elastic strain energy. After unloading, the second tension member restores the austenite state through the temperature rise, releases the stored energy to drive the reset, and at the same time, the elastic retraction of the first tension member assists in completing the recovery of the remaining displacement. When a single steel strand or viscous damper is used in the traditional joint, the energy dissipation and reset functions restrict each other, while in the present invention, the plastic energy dissipation and shape memory reset are activated in stages during the deformation process, which not only avoids premature stiffness degradation but also ensures rapid reset after unloading.

[0024] (4) The height of the corrugation peak determines the distribution of the frictional contact pressure, indirectly controlling the activation threshold of the first tension member. When the peak height is low, the frictional energy dissipation is delayed, and the plastic energy dissipation needs to be triggered in advance by reducing the slack margin of the first tension member. The corrugation wavelength and the pre-strain rate of the second tension member jointly regulate the reset response speed. The long wavelength extends the single frictional stroke, providing 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. At the initial stage of corrugation sliding, the pre-tightening force of the second tension member maintains the joint stiffness; when the corrugation enters the high-friction stage, the first tension member is tensioned to dissipate energy; during the plastic deformation stage at the root of the corrugation, the phase transformation driving force of the second tension member is triggered synchronously. When the joint bears dynamic loads, the corrugation structure adjusts the frictional energy dissipation intensity through geometric parameters, and the flexible tension member controls the reset ability through material properties. The two form a closed-loop feedback mechanism. This mechanism not only avoids the stress concentration caused by rigid connection in traditional joints but also overcomes the functional limitations of a single energy dissipation element. Description of the Drawings

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings;

[0026] Figure 1 It is the front view of an adjustable friction-enhanced gusset plate beam-column joint structure;

[0027] Figure 2Is an axonometric view of an adjustable friction-enhanced gusset plate beam-column joint structure;

[0028] Figure 3 Is a structural schematic diagram of the lower column;

[0029] Figure 4 Is a structural schematic diagram of the cross beam;

[0030] Figure 5 Is a structural schematic diagram of the corrugated structure;

[0031] Figure 6 Is a structural schematic diagram of the fastener;

[0032] In the figure: 1, column; 2, cross beam; 3, inner gusset plate; 4, outer gusset plate; 5, fastener; 6, channel plate; 7, flexible tension member; 8, corrugated structure; 11, upper column; 12, lower column; 13, connecting plate; 21, web; 22, flange; 31, round hole; 41, oblong hole; 42, limit block; 511, main nut; 512, gasket; 513, disc spring washer; 514, locknut; 71, first flexible tension member; 72, first articulated anchor; 73, second flexible tension member; 74, second articulated anchor; 81, first corrugated surface; 82, second corrugated surface. Detailed implementation manners

[0033] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0034] In the following description, many specific details are set forth in order to fully understand 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 by the specific embodiments disclosed below.

[0035] In the description of this application, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing this 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. Therefore, it should not be construed as a limitation on the scope of protection of this application. In addition, terms such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Therefore, features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of this invention, unless otherwise stated, the meaning of "a plurality" is two or more.

[0036] In the description of this application, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", "coupled" 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 communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood through specific circumstances.

[0037] Exemplary structure:

[0038] As Figure 1-6 shown, an adjustable friction-enhanced gusset plate beam-column joint structure includes a column 1 and a beam 2. Among them, the column 1 includes an upper column 11 and a lower column 12, and connecting plates 13 extending outward are provided at the ends of the upper column 11 and the lower column 12; the beam 2 is an H-shaped steel, including a web 21 and flange plates 22, and the flange plates 22 are connected to the connecting plates 13.

[0039] Inner gusset plates 3 and outer gusset plates 4 are symmetrically arranged on both sides of the web 21 in sequence; one side of the inner gusset plate 3 is fixed to the outer surface of the column 1; the outer gusset plate 4 is connected to the web 21 through fasteners 5; a slotted hole 41 is provided on the outer gusset plate 4, a round hole 31 is provided on the inner gusset plate 3, and the fastener 5 passes through the slotted hole 41, the web 21 and the round hole 31;

[0040] Mutually matching corrugated structures 8 are provided on the contact surfaces of the inner gusset plate 3 and the outer gusset plate 4 facing each other; the corrugated structure 8 includes a first corrugated surface 81 provided on the inner gusset plate 3 and a second corrugated surface 82 provided on the outer gusset plate 4, and there is a gap between the first corrugated surface 81 and the second corrugated surface 82.

[0041] Traditional beam-column joints are prone to brittle failure when subjected to dynamic loads and cannot effectively adjust the friction energy dissipation characteristics. On the one hand, the inner ear plate 3 is fixed 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 provided on the contact surfaces of the inner ear plate 3 and the outer ear plate 4, and the friction contact area is controlled through the gap to form an adjustable friction interface.

[0042] Specifically, the column 1 at the joint symmetrically connects the cross beams 2 on the left and right sides. The inner ear plates 3 on the two cross beams 2 are respectively welded and fixed to the two side surfaces of the column 1, and the outer ear plate 4 covers the areas of the two inner ear plates 3 and the middle column 1. When one side of the cross beam is loaded, the outer ear plate 4 transfers part of the load to the other side through the rigid connection in the middle, realizing load redistribution; the two corrugated structures 8 slide independently, and the coordinated deformation is achieved through the rigid middle section of the outer ear plate 4 to avoid unilateral overload. More specifically, when the joint bears static loads or small-amplitude dynamic loads, the tops of the wave crests of the corrugated structure 8 are slightly in contact, and the shear force is transmitted through the static friction force on the friction surface. At this time, the joint stiffness is close to that of the traditional rigid connection, ensuring the stability of the structure during normal use. The existence of the gap avoids stress concentration caused by hard contact and allows compensation for small thermal deformations at the same time. When the external load exceeds the static friction threshold, the outer ear plate 4 starts to slide along the oblong hole 41. The wave crests and wave troughs of the first corrugated surface 81 and the second corrugated surface 82 alternately engage and separate during this process, forming a periodic frictional resistance. During the sliding process, the slope of the side wall of the wave crest guides the contact pressure to be evenly distributed, avoiding the aggravation of local wear. Under the action of the reciprocating load, the change in the sliding speed of the outer ear plate 4 causes an inertial impact when the corrugated surface disengages. When the wave crest disengages, the vacuum effect briefly formed between the contact surfaces further absorbs energy, and at the same time, minor plastic deformations occur at the roots of the corrugations due to stress concentration, dissipating additional energy through material yielding. Through the above composite energy dissipation method, the problem that stress concentration is easily caused by rigid connection in beam-column joints under dynamic loads is effectively reduced.

[0043] As Figure 5 shown, the corrugation profiles of the first corrugated surface 81 and the second corrugated surface 82 are periodic continuous curves, and the wave crest positions of the first corrugated surface 81 correspond to the wave trough positions of the second corrugated surface 82, and the wave trough positions of the first corrugated surface 81 correspond to the wave crest positions of the second corrugated surface 82. The wave 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 corrugation extension direction.

[0044] On a planar friction interface, stick-slip phenomena are likely to occur, leading to uncontrollable vibration responses. By arranging wave crests and wave troughs alternately, progressive contact is formed, and a uniform gap is maintained along the sliding direction to avoid local jamming. As a result, the load response is roughly divided into three stages: In the first stage, only the tops of the wave crests are in contact, the contact pressure is elliptically distributed, the maximum pressure is located at the center of the wave crest, and the friction coefficient is stable at 0.15 - 0.18. In the second stage, the side walls of the corrugations gradually participate in the contact, the contact area increases exponentially, the peak of the contact pressure migrates towards the wave trough direction, and the friction coefficient rises to 0.25 - 0.30. In the third stage, the roots of the corrugations enter 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 microcracks in the roots of the corrugations further absorb energy. Meanwhile, closed cavities are formed in the wave trough regions, and the compression of the internal air generates a damping effect.

[0045] As Figure 4 shown, at least one channel-shaped plate 6 is provided on the web 21 of the cross beam 2. The channel-shaped plate 6 has a U-shaped cross-section structure, with the opening facing the web 21 and fixed to the web 21, forming a cavity inside; a flexible tension member 7 is threaded through the cavity, and both ends of the flexible tension member 7 are fixedly connected to the connecting plates 13 of the two side columns 1 respectively. The flexible tension member 7 includes a first flexible tension member 71 and a second flexible tension member 73.

[0046] Both ends of the first flexible tension member 71 are respectively fixed to the two side connecting plates 13 through first articulated anchors 72; the length of the first flexible tension member 71 is greater than the straight-line distance between the two anchoring points, forming a slack allowance. Specifically, the first flexible tension member 71 is made of ultra-high molecular weight polyethylene fibers or aramid fibers into a rope-like structure through a multi-strand braiding process, with a diameter of 10 - 20 mm and a fracture elongation rate of 3% - 5%. A 5% - 8% slack allowance is applied during installation. Among them, the slack allowance refers to the percentage by which the installation length of the first flexible tension member 71 is longer than the theoretical straight-line distance between the two end anchoring points, and the natural bending of the rope body in the cavity of the channel-shaped plate 6 realizes the non-preloaded slack state.

[0047] Both ends of the second flexible tension member 73 are respectively fixed to the two side connecting plates 13 through second articulated anchors 74; a preset pre-tightening force is applied to the second flexible tension member 73. Specifically, the second flexible tension member 73 uses 1860 MPa grade low-relaxation steel strands or shape memory alloy strands, with a diameter of 8 - 15 mm. The steel strands are coated with epoxy resin for corrosion protection, and the austenite finishing temperature of the shape memory alloy strands is 25 - 40 °C; 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 inhibit the initial slip of the cross beam 2. Among them, the pre-strain rate is the ratio of the tensile elongation to the initial length; during unloading, the steel strands are driven to reset through elastic recovery, and the shape memory alloy strands are driven to reset through the shape memory effect.

[0048] In a specific embodiment, the first flexible tension member 71 is made of ultra-high molecular weight polyethylene fibers by an 8-strand braiding process, with a diameter of 12 mm, a relaxation margin of 6%, and a breaking load of ≥85 kN; the second flexible tension member 73 is a nickel-titanium shape memory alloy stranded wire with a diameter of 10 mm, a pre-strain of 1.0%, an austenite finish temperature of 30 °C, and a pre-tightening force of 45 kN. In the elastic deformation stage, the first flexible tension member 71 remains in a relaxed state, and the fibers are naturally curved; the second flexible tension member 73 provides a basic constraint through the initial pre-tightening force and bears 5%-10% of the joint load. In the plastic deformation stage, when the joint displacement exceeds the threshold of 10-15 mm, the first flexible tension member 71 is gradually straightened under tension and bears 30%-50% of the shear force, and the fracture strain is controlled within 4%-6%; the nickel-titanium shape memory alloy stranded wire of the second flexible tension member 73 undergoes a martensitic transformation, generating a recoverable strain of 6%-8%, while maintaining 60%-70% of the initial pre-tightening force. In the self-resetting stage, when unloading, the nickel-titanium shape memory alloy stranded wire of the second flexible tension member 73 generates a recovery stress of 300-400 MPa by being electrically heated or the ambient temperature rising above the austenite finish temperature, driving the joint to reset to the initial position within 30-60 seconds; the polyethylene fibers of the first flexible tension member 71 rely on the elastic retraction of the molecular chains to assist in completing the final 5%-10% of the reset stroke; after resetting, the flexible tension member 7 can withstand subsequent cyclic loads.

[0049] As Figure 4 shown, the extending direction of the oblong hole 41 of the outer ear plate 4 is parallel to the axial direction of the cross beam 2, and the length of the oblong hole 41 is 1.5-2 times the diameter of the screw of the fastener 5.

[0050] As Figure 6 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 round hole 31, a main nut 511 on the inner side of the inner ear plate 3 on the bolt rod, a gasket 512 closely attached to the outer surface of the outer ear plate 4, a conical spring washer 513 sleeved on the bolt rod and closely attached to the gasket 512, and a locknut 514 on the bolt rod and compressing the conical spring washer 513.

[0051] Traditional fasteners are prone to progressive loosening under complex vibration spectra and cannot compensate for the loss of pre-tightening force caused by material creep. The right-handed rotation of the main nut and the left-handed rotation of the locknut cooperate in the reverse direction to provide a basic clamping force, and the conical spring washer 513 maintains dynamic pre-tightening. On the one hand, the left-handed thread of the locknut 514 and the right-handed thread of the main nut 511 form a helical interlock. The vibration energy is converted into an additional tightening torque of the locknut to achieve a dynamic self-tightening effect. On the other hand, the elastic deformation of the conical spring washer 513 compensates for the creep relaxation of the bolt and maintains the pre-tightening force.

[0052] As Figure 2As shown in the figure, limit blocks 42 are provided at both ends of the oblong hole 41 of the outer ear plate 4; the limit blocks 42 are rectangular steel blocks with a thickness greater than that of the outer ear plate 4, and the limit blocks 42 are welded and fixed to the surface of the outer ear plate 4 and are located at the end of the oblong hole 41. When the sliding amount of the outer ear plate 4 reaches the end of the oblong hole 41, the limit block 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 limit block 42 ensures that it does not suffer from crushing failure under high impact loads, providing ultimate safety protection for the structure.

[0053] 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 carbon coating.

[0054] Embodiment 1

[0055] An adjustable friction-enhanced ear plate beam-column joint structure specifically includes the following components:

[0056] The column 1 is a box-section column with a cross-sectional size of 400 mm × 400 mm, including an upper column 11 and a lower column 12 that are welded and fixed. Connecting plates 13 with a thickness of 12 mm are welded to the ends of the upper column 11 and the lower column 12.

[0057] The cross beam 2 is an H-shaped steel, including a wing plate 22 of 200 mm × 12 mm and a web 21 of 300 mm × 8 mm. The wing plate 22 is connected to the connecting plate 13 through a high-strength bolt group.

[0058] The inner ear plate 3 is an NM450 wear-resistant steel plate with a thickness of 10 mm, which is welded to the outer surface of the column 1 and is provided with 6 round holes 31.

[0059] The outer ear plate 4 is an NM450 wear-resistant steel plate with a thickness of 10 mm, and is slidably connected to the web 21 through 12 oblong holes 41 with a length of 30 mm.

[0060] The corrugated structure 8 includes a first corrugated surface 81 and a second corrugated surface 82 provided 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 with their crests and troughs staggered. The crest height is 2 mm, the wavelength is 15 mm, the gap width is less than 2 mm, and a tungsten carbide coating with a thickness of 0.1 mm is sprayed on the surface.

[0061] The channel 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 through a high-strength bolt group.

[0062] The flexible tension member 7 includes a first flexible tension member 71 and a second flexible tension member 73. The first flexible tension member 71 is an 8-strand braided ultra-high molecular weight polyethylene fiber rope with a diameter of 12 mm and a slack allowance of 5%. It is connected to the connecting plates 13 on both sides through a first articulated anchor 72. The second flexible tension member 73 is a nickel-titanium shape memory alloy stranded wire 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. It is connected to the connecting plates 13 on both sides through a second articulated anchor 74.

[0063] The fastener 5 includes a bolt rod passing through the oblong hole 41, the web 21, and the round hole 31, a main nut 511 inside the inner ear plate 3 on the bolt rod, a gasket 512 closely attached to the outer surface of the outer ear plate 4, a disc spring washer 513 sleeved on the bolt rod and closely attached to the gasket 512, and a locknut 514 located on the bolt rod and compressing the disc spring washer 513.

[0064] The limit block 42 is a rectangular steel block welded to the end of the oblong hole 41.

[0065] Example 2

[0066] Different from Example 1, in this example, the peak height of the corrugated structure 8 is 3.5 mm and the wavelength is 22.5 mm; the slack allowance of the first flexible tension member 71 is 6.5%; the pre-strain rate of the second flexible tension member 73 is 1.0% and the pre-tightening force is 45 kN.

[0067] Example 3

[0068] Different from Example 1, in this example, the peak height of the corrugated structure 8 is 5 mm and the wavelength is 30 mm; the slack allowance of the first flexible tension member 71 is 8%; the pre-strain rate of the second flexible tension member 73 is 1.2% and the pre-tightening force is 54 kN.

[0069] Example 4

[0070] Different from Example 1, in this example, the peak height of the corrugated structure 8 is 3.5 mm and the wavelength is 15 mm.

[0071] Example 5

[0072] Different from Example 1, in this example, the peak height of the corrugated structure 8 is 3.5 mm and the wavelength is 30 mm.

[0073] Example 6

[0074] Different from Example 1, in this example, the peak height of the corrugated structure 8 is 2 mm and the wavelength is 22.5 mm.

[0075] Example 7

[0076] Different from Embodiment 1, in this embodiment, the peak height of the corrugated structure 8 is 5 mm and the wavelength is 22.5 mm.

[0077] Embodiment 8

[0078] Different from Embodiment 1, in this embodiment, the slack allowance of the first flexible tension member 71 is 8%; the pre-strain rate of the second flexible tension member 73 is 1.2%, and the pre-tightening force is 54 kN.

[0079] Comparative Example 1

[0080] Different from Embodiment 1, in this comparative example, the outer ear plate 4 and the flexible tension member 7 are not provided.

[0081] Experimental Example 1

[0082] Based on the node structures provided in Embodiments 1-8 and Comparative Example 1, specimens are made, and the change parameters of the specimens based on different embodiments and comparative examples are as shown in the following table:

[0083] Table 1 Comparison Table of Specimens

[0084]

[0085] In this experimental example, the loading device uses an MTS hydraulic servo loading system (range ±500 kN, stroke ±150 mm), equipped with a reaction frame and a fixture system. The column 1 of the specimen is anchored to the laboratory rigid base through anchor bolts, the free end of the cross beam 2 is connected to the MTS actuator through a universal hinge, the slack allowance of the first flexible tension member 71 is controlled by the calibrated length, the pre-strain rate of the second flexible tension member 73 is controlled by a hydraulic tensioning device, and strain gauges are installed. The loading procedure of the loading device includes preloading, static stage, reciprocating loading and failure stage. Among them, the preloading is cycled 3 times with ±5 kN to eliminate the assembly gap and calibrate the sensors; in the static stage, it is unidirectionally loaded to 50 kN at a rate of 2 mm / min; the reciprocating loading is displacement-controlled, with a sine wave of 0.5 Hz and an amplitude of ±50 mm, lasting for 10 cycles, and the load, displacement and strain parameters are collected; in the failure stage, it is loaded at a rate of 5 kN / s until the bearing capacity drops to 80% of the peak value.

[0086] The experimental method refers to JGJ / T 101-2015 "Code for Building Seismic Tests". Calculate the proportion of friction and plastic deformation energy dissipation in the total input energy to reflect the collaborative energy dissipation efficiency, denoted as the composite energy dissipation coefficient η (%); refer to ISO 16670:2003 "Test Methods for Structural Seismic Joints", calculate the proportion of residual displacement after unloading to measure the self-centering ability, denoted as the residual displacement ratio δ (%); refer to ASTM E2126-11 "Test Methods for Structural Stiffness", calculate the load-displacement slope in the elastic stage to reflect the serviceability stiffness, which is the initial stiffness K (kN / mm); refer to EN 12512:2001 "Code for Cyclic Testing of Steel Joints", calculate the critical load for the joint to enter plastic deformation to determine the energy dissipation start threshold, denoted as the yield load F y (kN); refer to ISO 12106:2017 "Metallic Materials - Fatigue Testing", calculate the maximum lateral load-carrying capacity of the joint to reflect the safety reserve, denoted as the ultimate load-carrying capacity F u (kN); refer to ASTM G115-10 "Standard Test Method for Measuring Coefficient of Friction", calculate the dynamic friction coefficient of the contact surface to determine the friction energy dissipation efficiency, denoted as the friction coefficient μ, and the experimental results are shown in the following table:

[0087] Table 2 Data Sheet of Key Parameters

[0088]

[0089] The experimental data show that the composite energy dissipation coefficient η first increases and then decreases with the increase of the wave peak height (η of Example 1 → Example 2 → Example 7 groups are 24.7%, 38.2%, 36.7% respectively), indicating that too high a wave peak (5 mm) will cause uneven contact pressure distribution and offset the gain in friction efficiency; the residual displacement ratio δ is negatively correlated with the pre-strain rate (δ = 45.2% corresponding to the pre-strain rate of 0.8% in Example 1 group, and δ = 19.8% corresponding to the pre-strain rate of 1.2% in Example 8 group), proving that a high pre-strain rate improves the reset ability by strengthening the shape memory effect; the ultimate load-carrying capacity in the long wavelength (30 mm) group (F u = 238.1 kN in Example 5 group) is 2.9% higher than that in the short wavelength (15 mm) group (F u = 231.4 kN in Example 4 group) because the compression damping of the wave valley cavity delays the stress concentration.

[0090] In Example 2 group, the wave peak height is 3.5 mm, the wavelength is 22.5 mm, the relaxation margin is 6.5%, and the pre-strain rate is 1.0%, and the results are η = 38.2% (the highest), δ = 18.3% (the lowest), F u= 245.6 kN (highest), μ = 0.31 (second highest), with the best comprehensive performance. This is because, on the one hand, during the initial stage of sliding (displacement < 10 mm), only the top of the 3.5-mm wave crest is in contact, and the friction coefficient is stable at 0.15 - 0.18. At this time, the relaxation margin of the polyethylene fiber is 6.5%, allowing the web 21 to deform freely and avoiding premature triggering of plastic energy dissipation; the 22.5-mm wavelength matches the 0.5-Hz loading frequency, synchronizing the wave crest detachment period (about 0.22 s) with the phase change response time of the NiTi stranded wire (0.2 - 0.3 s) and maximizing the compression damping effect of the wave trough cavity. On the other hand, the 6.5% relaxation margin ensures that the polyethylene fiber gradually straightens when the displacement > 15 mm, bearing 30% - 40% of the shear force. The molecular chain slip energy dissipation of the fiber and the corrugation friction form a complement; the 1.0% pre-strain rate causes the NiTi stranded wire to transform from austenite to martensite when the displacement > 20 mm, generating a recovery stress of 300 - 400 MPa to drive the node to reset. Further, the progressive contact of the 3.5-mm wave crest delays the triggering of plastic deformation, buys time for the 1.0% pre-strain rate stranded wire to have a phase change response, and forms a sequential collaborative chain of first friction energy dissipation, then plastic deformation, and finally shape memory reset.

[0091] In Example 1 group, the wave crest height is 2 mm, the wavelength is 15 mm, the relaxation margin is 5%, and the pre-strain rate is 0.8%. The obtained results are η = 24.7% (lowest), δ = 45.2% (highest), F u = 185.3 kN (lowest), μ = 0.18 (lowest), and the performance deteriorates comprehensively. This is because the 2-mm low wave crest causes the friction contact area to reach saturation at a displacement of 8 mm (the peak contact pressure is 6.2 MPa). Subsequently, the subsequent load cannot be dissipated through friction and instead triggers local buckling of the web; the 15-mm short wavelength results in a wave crest detachment frequency as high as 0.67 Hz, exceeding the phase change response limit of the NiTi stranded wire (0.5 Hz), and the compression damping of the wave trough cavity is not fully formed. In addition, the 5% low relaxation margin limits the extensibility of the polyethylene fiber, and its fracture elongation is only 3.8%, breaking at a displacement of 10 mm and losing the plastic energy dissipation function; the 0.8% low pre-strain rate results in insufficient phase change driving force for the NiTi stranded wire, and it cannot overcome the friction residual resistance after unloading, resulting in a δ as high as 45.2%. The 2-mm low wave crest requires a higher relaxation margin (≥ 7%) to extend the time window for the fiber to participate in energy dissipation, but the 5% relaxation margin in Example 1 group exacerbates the premature fracture of the fiber, causing failure.

[0092] Based on the ideal embodiments of the present invention as inspiration, through the above description, relevant personnel can make various changes and modifications completely within the scope without departing from the technical idea of this invention. The technical scope of this 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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