Energy absorption structure in the core and axial steel damper

Abstract

The present invention relates to an energy absorbing structure at the core and an axial steel damper. The axial steel damper includes an energy absorbing structure at the core and a peripheral restraint component, and the energy absorbing structure at the core includes at least one austenitic steel plate and one ferritic steel plate, and the ferritic steel plate must be adjacent to the austenitic steel plate and can only be connected by welding. The microstructure of the austenitic steel plate is mainly metastable austenite, and when subjected to cyclic alternating tensile and compressive plastic deformation, a reversible phase transformation between austenite and strain-induced ε martensite occurs inside the austenitic steel plate. The ratio of the limit allowable displacement and the yield displacement of the axial steel damper according to the present invention is 10 or more, and the limit allowable displacement is 1 / 60 or more of the length of the axial steel damper, and under the condition of this limit allowable displacement, the axial steel damper can complete at least 30 cycles of cyclic alternating tensile and compressive plastic deformation.

Description

Technical Field

[0001] The present invention belongs to the technical field of structural engineering and relates to an energy absorption structure in a core and an axial steel damper.

Background Art

[0002] Both high-intensity earthquakes and long-term external vibrations can cause significant damage to high-rise buildings and structures. By using energy absorption and shock absorption devices and technologies, external vibration energy can be effectively absorbed, and damage to buildings and structures can be minimized. Buckling-restrained braces are common axial energy absorption and shock absorption elements and are widely used in civil structures due to their direct force transmission path and excellent economy. Under small vibrations, buckling-restrained braces can provide additional rigidity to the beam and column structure and reduce structural deformation. Under large vibrations, buckling-restrained braces can yield in both tension and compression and exhibit excellent deformation recovery characteristics and energy absorption capacity.

[0003] At present, buckling-restrained braces mainly use steel materials such as LY225 low-yield-point steel and Q235 steel as energy-absorbing core materials (both of the above steel grades are low-carbon ferrite steels). The buckling-restrained braces manufactured with the above types of steel can often only ensure a certain rigidity when frequent earthquakes ("minor earthquakes") or earthquakes occurring once every 475 years ("moderate earthquakes") occur, but there is no substantial yield deformation for absorbing seismic energy. More importantly, it is restricted by the lower ductility and low-cycle fatigue deformation ability of the steel grade, and the cumulative plastic deformation and cumulative plastic energy absorption effect caused by the repeated deformation of the above steel grades are limited. Therefore, when a rare earthquake ("major earthquake") occurs, the buckling-restrained braces manufactured with the above types of steel will undergo fatigue failure after a relatively small number of cycles of tensile-compression repeated loading. Also, in the case of rare earthquakes or extremely rare earthquakes, the buckling-restrained braces cannot achieve the same redundancy as the main structure of the building (that is, the buckling-restrained braces break earlier than the main structure of the building, and thereby, the main structure of the building cannot be further protected from the buckling-restrained braces). In summary, the buckling-restrained braces manufactured with low-carbon ferrite steel cannot play a role in seismic protection under earthquakes of different intensities.

[0004] Fe-Mn-Si austenitic alloys with low stacking fault energy in a specific component range have excellent low-cycle fatigue characteristics and welding performance, and may be used as elasto-plastic degrading steel materials for manufacturing buckling-restrained braces. Therefore, this type of buckling-restrained brace can have excellent cumulative plastic deformation capacity (i.e., the core plate can withstand large cumulative tensile and compressive displacements before the buckling-restrained brace undergoes fatigue failure). The fundamental reason why Fe-Mn-Si alloys with low stacking fault energy have excellent low-cycle fatigue characteristics is that dislocation plane slip and reversible martensitic phase transformation occur inside the material during repeated deformation. However, compared with LY225 low-yield-point steel and Q235 steel, the above Fe-Mn-Si alloys have high yield strength, which may increase the yield load and yield displacement of the buckling-restrained brace, and the ductility may still be low (here, "ductility" is represented by the ratio of the limit allowable displacement to the yield displacement of the buckling-restrained brace or the axial energy absorption element). Correspondingly, in small and moderate earthquakes, it is difficult for the energy absorption brace to play the role of energy absorption and shock absorption, and in large earthquakes, the force applied to the main structure of the building by the energy absorption brace at the joint will become very large. Therefore, for buckling-restrained braces made of Fe-Mn-Si alloy steel with low stacking fault energy, the protection for the main structure of the building is limited. Furthermore, the degree of work hardening of Fe-Mn-Si alloys within one deformation cycle is relatively high, which will also weaken the energy absorption effect of the buckling-restrained brace. Due to the above reasons, the wide application of low stacking fault energy Fe-Mn-Si alloys as energy absorption and shock absorption materials in actual engineering is limited.

Summary of the Invention

[0005] Based on the above technical situation, there is an urgent need to develop an axial steel damper with a small yield displacement, excellent ductility and cumulative plastic deformation capacity, and the same redundancy as the main structure of a building. Therefore, the present invention provides an energy absorption structure in the core and an axial steel damper. The axial steel damper provided by the present invention can play a role in energy absorption and shock absorption under earthquakes of different intensities, and can provide seismic protection for buildings, and can greatly improve the seismic protection performance of buildings instead of the conventional buckling-restrained brace.

[0006] Compared with the conventional buckling-restrained brace, the axial steel damper and the energy absorption structure in the core according to the present invention can achieve excellent ductility and cumulative plastic deformation capacity, and have the same redundancy as the main structure of the building. Compared with the buckling-restrained brace made of a low-laminated defect energy Fe-Mn-Si austenitic alloy steel that may be used, the axial steel damper and the energy absorption structure in the core according to the present invention have a small yield displacement, excellent ductility, and low cost.

[0007] The object of the present invention can be achieved by the following technical solutions.

[0008] The present invention first provides an energy absorption structure in the core for an axial steel damper that absorbs external vibration energy when the axial steel damper undergoes plastic deformation of tension and compression alternately periodically, The energy absorption structure in the core includes at least one steel plate of austenite phase and one steel plate of ferrite phase. The steel plate of ferrite phase must be adjacent to the steel plate of austenite phase and can only be connected by welding. The welding seam for connection between the steel plate of austenite phase and the ferrite steel plate is parallel to the axial direction of the steel damper and the energy absorption structure in the core, The microstructure of the austenite-phase steel sheet is composed of metastable austenite and thermally induced ε-martensite with a volume fraction of 10% or less, the average metastable austenite crystal grain size is 400 μm or less, and during tensile or compressive plastic deformation, the metastable austenite of the austenite-phase steel sheet is induced to undergo ε-martensite phase transformation by the action of strain, and the α'-martensite phase transformation is suppressed. When periodic alternating tensile and compressive plastic deformation is applied, a reversible phase transformation occurs between austenite and strain-induced ε-martensite inside the austenite-phase steel sheet. The microstructure of the ferrite-phase steel sheet is mainly ferrite, and the average ferrite crystal grain size is 200 μm or less. The yield strength of the austenite-phase steel sheet is 220 MPa or more, and the elongation is 40% or more. The yield strength of the ferrite-phase steel sheet is less than 180 MPa, and the elongation is 30% or more. The thickness of the austenite-phase steel sheet is 0.4 times or more of the thickness of the ferrite-phase steel sheet. In the energy absorption structure at the core, the ratio of the total cross-sectional area of the core part of the energy absorption of all ferrite-phase steel sheets to the total cross-sectional area of the core part of the energy absorption of all austenite-phase steel sheets is 0.6 or more.

[0009] In the energy absorption structure at the core, when both sides of the ferrite-phase steel sheet are not simultaneously adjacent to and connected to the austenite-phase steel sheet, the ratio of the distance from the welding joint for connection between the ferrite-phase steel sheet and the adjacent austenite-phase steel sheet to any non-welded side of the core part of the energy absorption of the ferrite-phase steel sheet to the thickness of the ferrite-phase steel sheet is 25 or less.

[0010] In the energy absorption structure of the core, when the geometric shape of the cross-section of the ferrite-phase steel plate or the austenite-phase steel plate does not change along the longitudinal direction, the energy absorption core portion of the ferrite-phase steel plate or the austenite-phase steel plate is, that is, the entire length of the ferrite-phase steel plate or the austenite-phase steel plate. In this case, the cross-section of the energy absorption core portion of the ferrite-phase steel plate or the austenite-phase steel plate is, that is, the cross-section of the ferrite-phase steel plate or the austenite-phase steel plate. When the geometric shape of the cross-section of the ferrite-phase steel plate or the austenite-phase steel plate has the characteristic that both ends are wide and the center is narrow along the longitudinal direction, the energy absorption core portion of the ferrite-phase steel plate or the austenite-phase steel plate is the narrow portion at the center of the ferrite-phase steel plate or the austenite-phase steel plate. In this case, it is defined that the cross-section of the energy absorption core portion of the ferrite-phase steel plate or the austenite-phase steel plate is, that is, the cross-section of the narrow portion at the center of the ferrite-phase steel plate or the austenite-phase steel plate.

[0011] The present invention limits the energy absorption structure in the core to include at least one austenite-phase steel plate and one ferrite-phase steel plate. The microstructure of the austenite-phase steel plate is metastable austenite and thermally induced ε-martensite with a volume fraction of 10% or less. The purpose is to alternately apply tensile and compressive loads to promote the generation of thin-sheet single-variants of strain-induced ε-martensite with crystallographic characteristics inside the steel plate, avoid the influence with thermally induced ε-martensite in the original matrix structure, promote the reversible phase transformation between austenite and strain-induced ε-martensite, reduce the generation of matrix crystal defects in the austenite steel plate in the structure, and suppress the propagation of fatigue cracks. Thereby, the austenite steel plate can exhibit excellent low-cycle fatigue performance and cumulative plastic deformation ability. As a result, it is to improve the low-cycle fatigue performance and cumulative plastic deformation ability of the entire energy absorption structure in the core (when the energy absorption structure in the core is used in an axial steel damper, that is, the axial steel damper).

[0012] Furthermore, the present invention restricts the metastable austenite inside the austenite-phase steel plate from suppressing the α′ martensite phase transformation during tensile or compressive plastic deformation. This is because when the metastable austenite undergoes excessive α′ martensite phase transformation due to the action of plastic strain, local deformation is likely to occur inside the steel plate, and the low-cycle fatigue performance of the austenite-phase steel plate will decrease rapidly. The present invention restricts the average metastable austenite crystal grain size from exceeding 400 μm. This is because if the austenite crystal grains are too coarse, the reversible phase transformation between austenite and strain-induced ε martensite will be significantly suppressed, and the fatigue resistance performance of the austenite-phase steel plate will decrease significantly. The present invention strictly restricts the microstructure of the austenite-phase steel plate, aiming to ensure that the austenite-phase steel plate can withstand large strain fatigue deformation, and to ensure that the axial steel damper can function without early fatigue failure even under medium-intensity and high-intensity earthquakes.

[0013] Since the ferrite-phase steel plate has a low yield strength, a high Young's modulus, and a low degree of work hardening during repeated deformation cycles, it contributes to reducing the yield load, yield displacement, and the degree of work hardening during repeated deformation cycles of the entire energy absorption structure (i.e., the axial steel damper) in the core. Thereby, the steel damper can achieve yield and energy absorption even in small and medium-scale earthquakes. The present invention restricts the average ferrite crystal grain size from exceeding 200 μm. This is because if the ferrite crystal grains are too coarse, fatigue cracks are likely to occur and propagate from the grain boundaries, and the fatigue resistance of the ferrite-phase steel plate will decrease significantly. Therefore, the restriction on the ferrite grain size (and elongation rate) aims to ensure appropriate fatigue resistance of the ferrite-phase steel plate.

[0014] In the energy absorption structure of the core, the ferrite-phase steel plate and the austenite-phase steel plate need to be closely connected by welding. Otherwise, the special role of the overall energy absorption structure of the austenite-phase steel plate and the ferrite-phase steel plate in the core does not exist or it is difficult to fully play. This is because when the austenite-phase steel plate and the ferrite-phase steel plate are closely connected, the austenite-phase steel plate restricts the deformation of the ferrite-phase steel plate. Due to this restricted internal stress, the fatigue resistance of the ferrite-phase steel plate is improved (i.e., the special role). When fatigue fracture occurs in the core part of energy absorption, the two types of steel plates often break at the same part. When the same type of steel plates are connected, such a restraint mechanism disappears. That is, when a ferrite-phase steel plate and another ferrite-phase steel plate are adjacent and welded, the fatigue resistance of the two ferrite-phase steel plates cannot be improved. When the two types of steel plates are not connected, first, there is no restraint mechanism of the austenite-phase steel plate on the deformation of the ferrite-phase steel plate, and the fatigue resistance of the overall energy absorption structure in the core cannot be improved. Furthermore, since the austenite-phase steel plate is significantly superior in fatigue resistance compared to the ferrite-phase steel plate, in the plastic deformation process of alternately applying tension and compression, the ferrite-phase steel plate breaks first, and the loading capacity of the axial steel damper decreases. Therefore, the present invention limits that the ferrite-phase steel plate in the energy absorption structure of the core must be closely connected to the austenite-phase steel plate by welding.

[0015] The present invention limits the yield strength of the austenite-phase steel plate constituting the energy absorption structure in the core to 220 MPa or more, the elongation rate to 40% or more, the yield strength of the ferrite-phase steel plate to less than 180 MPa, and the elongation rate to 30% or more. The main purpose of limiting the mechanical properties of the two types of steel plates is to ensure that the two types of steel plate materials have good plastic deformation ability and fatigue characteristics, and to enable the axial steel damper to have the following ductility and cumulative deformation characteristics: the ratio of the limit allowable displacement to the yield displacement is 10 or more, and the limit allowable displacement is 1 / 60 or more of the length of the energy absorption structure (or axial steel damper) in the core. Under the condition of this limit allowable displacement, the axial steel damper can complete at least 30 cycles of alternating plastic deformation of tension and compression, and the reduction in load capacity is less than 15%.

[0016] The present invention limits the thickness of the austenite-phase steel plate to 0.4 times or more of the thickness of the ferrite-phase steel plate. This is because when the thickness of the austenite-phase steel plate is less than 0.4 times the thickness of the ferrite-phase steel plate, it is difficult for the austenite-phase steel plate to sufficiently restrain the deformation of the ferrite-phase steel plate through the connection weld seam during the alternating plastic deformation of tension and compression.

[0017] In the present invention, when the ratio of the total cross-sectional area of the core portions of the energy absorption of all ferrite-phase steel plates to the total cross-sectional area of the core portions of the energy absorption of all austenite-phase steel plates is too small (less than 0.6), the deformation and loading of the energy absorption structure in the core are mainly dominated by the austenite-phase steel plates, whereby the yield load and yield displacement of the energy absorption structure in the core increase significantly, and the ductility of the energy absorption structure in the core and the axial steel damper decreases significantly (the ductility of the steel damper is less than 10). Therefore, the present invention limits the ratio of the total cross-sectional area of the core portions of the energy absorption of all ferrite-phase steel plates to the total cross-sectional area of the core portions of the energy absorption of all austenite-phase steel plates to less than 0.6. Further, from the viewpoint of reducing the yield displacement of the energy absorption structure in the core, it is preferable that the ratio of the total cross-sectional area of the core portions of the energy absorption of all ferrite-phase steel plates to the total cross-sectional area of the core portions of the energy absorption of all austenite-phase steel plates is 0.8 or more.

[0018] In one embodiment of the present invention, when both sides of the ferrite-phase steel plate are not simultaneously connected adjacent to the austenite-phase steel plate, the ratio of the distance from the welding joint for connection between the ferrite-phase steel plate and the adjacent austenite-phase steel plate to any non-welded side of the core portion of the energy absorption of the ferrite-phase steel plate to the thickness of the ferrite-phase steel plate is 25 or less. Here, as the connection method between the ferrite-phase steel plate and the adjacent austenite-phase steel plate, the following two types are conceivable.

[0019] First, the ferrite-phase steel plate is adjacent to the austenite-phase steel plate on only one side, that is, the welding seam for connecting the two types of steel plates is located on one side of the ferrite-phase steel plate. In this case, there is only one non-welded side on the ferrite-phase steel plate. General connection methods include connecting two ferrite-phase steel plates and one austenite-phase steel plate to form a cross-shaped structure by vertically arranging the two ferrite-phase steel plates above and below the austenite-phase steel plate respectively, arranging the ferrite-phase steel plate perpendicular to the austenite-phase steel plate, and connecting one ferrite-phase steel plate and one austenite-phase steel plate to form a T-shaped structure such that the welding seam for connecting the two types of steel plates is located on the austenite-phase steel plate (i.e., the welding seam for connection is located between both sides of the austenite-phase steel plate).

[0020] Second, the welding seam for connecting the two types of steel plates is located on the ferrite-phase steel plate, that is, the welding seam for connection is located between both sides of the ferrite-phase steel plate (the welding seam for connection is not located on either side of the ferrite-phase steel plate). In this case, there are two non-welded sides on the ferrite-phase steel plate. General connection methods include connecting two ferrite-phase steel plates and one austenite-phase steel plate to form an I-shaped structure by vertically arranging the austenite-phase steel plate between the two ferrite-phase steel plates, arranging the ferrite-phase steel plate perpendicular to the austenite-phase steel plate, and connecting one ferrite-phase steel plate and one austenite-phase steel plate to form a T-shaped structure such that the welding seam for connecting the two types of steel plates is located on the ferrite-phase steel plate (i.e., the welding seam for connection is located between both sides of the ferrite-phase steel plate).

[0021] In the above two cases, when the ratio of the distance from the welding joint for connection for restraint to any non-welded side of the core portion of the energy absorption of the ferrite-phase steel plate to the thickness of the ferrite-phase steel plate is too large (greater than 25), the restraint effect received by a part of the material away from the welding joint of the ferrite-phase steel plate is almost lost, and this part of the material is more likely to undergo fatigue fracture than the material near the welding joint for restraint. As a result, it leads to the invalidation and destruction of the entire ferrite-phase steel plate and the energy absorption structure in the core. Therefore, the present invention limits the ratio of the distance from the welding joint for connection for restraint to any non-welded side of the core portion of the energy absorption of the ferrite-phase steel plate to the thickness of the ferrite-phase steel plate to 25 or less.

[0022] When both sides of the ferrite-phase steel plate are connected to the adjacent austenite-phase steel plates, since the ferrite-phase steel plate is restrained and protected from both sides, fatigue cracks do not occur from the two side surfaces, and the fatigue resistance of the ferrite-phase steel plate is significantly improved. In the present invention, when both sides of the ferrite-phase steel plate are connected to the austenite-phase steel plates, the distance between the welding joints on both sides of the ferrite-phase steel plate is not generally limited, but it is necessary to satisfy the condition that "the ratio of the total cross-sectional area of the core portions of the energy absorption of all ferrite-phase steel plates to the total cross-sectional area of the core portions of the energy absorption of all austenite-phase steel plates is 0.6 or more". From the viewpoint of the stability of the energy absorption structure in the core, it is recommended that the distance between the welding joints on both sides of the ferrite-phase steel plate does not exceed 80 times the thickness of the ferrite-phase steel plate. When both sides of the ferrite-phase steel plate are connected to the austenite-phase steel plates, one ferrite-phase steel plate and two austenite-phase steel plates are connected to form an I-shaped structure by arranging the ferrite-phase steel plate vertically between the two austenite-phase steel plates.

[0023] The present invention defines the limit allowable displacement and the yield displacement of an axial steel damper. The limit allowable displacement is the maximum displacement allowable for an axial steel damper when tensile and compressive plastic deformations are periodically and alternately applied. At this maximum displacement, the axial steel damper can withstand at least 30 cycles of repeated plastic deformations of tension and compression. When the repeated deformation displacement exceeds this maximum allowable displacement, the axial steel damper cannot complete 30 cycles of repeated deformation, breaks, and becomes ineffective. The yield displacement represents the displacement corresponding to the yield deformation that occurs when the axial steel damper is periodically and alternately subjected to tension and compression at the limit allowable displacement. Figure 1 shows the repeated stress-strain curve formed when the axial steel damper is periodically and alternately subjected to plastic deformations of tension and compression at the allowable limit displacement. The elastic stiffness of the axial steel damper is obtained from the unloading part of the repeated stress-strain curve. When the center of the repeated stress-strain curve is not at the origin of the coordinate axes, the maximum displacement of the tensile part of the repeated stress-strain curve is u d,max (t) and the maximum displacement of the compression part of the repeated stress-strain curve is u d,max (c) . The limit allowable displacement u d,max is calculated as 1 / 2(u d,max (t) +u d,max (c) ). When the center of the repeated stress-strain curve is at the origin of the coordinate axes, the maximum displacement of the tensile part of the repeated stress-strain curve is the same as the maximum displacement of the compression part. In this case, u d,max =u d,max (t) =u d,max (c) . The elastic stiffness corresponding to the unloading part of the tensile part of the repeated stress-strain curve is K d (t) , and the elastic stiffness corresponding to the unloading part of the compression part of the repeated stress-strain curve is K d (c) . When K d (t) ≠K d (c) , the elastic stiffness K d of the axial steel damper is 1 / 2(K d (t) +K d(c) ) is calculated as K d (t) =K d (c) When it is, the elastic rigidity of the axial steel damper is K d =K d (t) =K d (c) becomes. Draw a straight line passing through the origin of coordinates and having a slope of elastic rigidity K d , and the intersection of the straight line and the tensile part of the repeated stress-strain curve is the yield displacement u during repeated tensile deformation dy (t) , and the intersection of the straight line and the compression part of the repeated stress-strain curve is the yield displacement u during repeated tensile deformation dy (c) . The yield displacement u of the axial steel damper dy is 1 / 2(u dy (t) +u dy (c) ). From the limit allowable displacement u d,max and the yield displacement u dy , the ratio of u d,max to u dy of the axial steel damper, that is, the ductility of the steel damper can be obtained.

[0024] In one embodiment of the present invention, the mass fraction of the chemical components of the austenite-phase steel plate is limited to C≦0.15%, 22.0%≦Mn≦34.0%, 3.5%≦Si≦5.5%, Al≦2.5%, Ni≦5.0%, Cu≦2.0%, P≦0.03%, S≦0.03%, N≦0.02%, and the balance is Fe and inevitable impurity elements, where the mass content ratios of Al, Ni, and Cu satisfy Ni / Cu≧0.25 and Al + 0.4Ni + 0.25Cu≦3.5%.

[0025] The microstructure of the material satisfying the above component requirements is metastable austenite and thermally induced ε-martensite with a volume fraction of 10% or less. The metastable austenite undergoes a reversible ε-martensite phase transformation under repeated tensile and compressive loads (i.e., the metastable austenite and strain-induced ε-martensite undergo an austenite ⇔ ε-martensite transformation under repeated loads), and the α'-martensite phase transformation is suppressed. As a result, the steel plate material has excellent low-cycle fatigue performance.

[0026] Without changing the above basic microstructure characteristics, the chemical composition of the austenite-phase steel plate can contain a small amount of Cr element, and the present invention limits the mass fraction of the Cr element to Cr ≦ 2%.

[0027] When the above alloy components are present and the average metastable austenite crystal grain size is 400 μm or less, the yield strength of the austenite-phase steel plate is 220 MPa or more, and the elongation is 40% or more.

[0028] In one embodiment of the present invention, the mass fractions of the chemical components of the ferrite-phase steel plate are limited to C ≦ 0.1%, Mn ≦ 1.0%, Si ≦ 0.8%, Ti ≦ 0.15%, Nb ≦ 0.1%, V ≦ 0.2%, P ≦ 0.03%, S ≦ 0.03%, N ≦ 0.02%, and the balance is Fe and unavoidable impurity elements.

[0029] The microstructure of the material satisfying the above component requirements is mainly ferrite. Without changing the above basic microstructure characteristics, the chemical composition of the ferrite-phase steel plate can contain a small amount of Cu, Cr, and Ni elements, and the present invention limits the mass fractions of the Cu, Cr, and Ni elements to Cu ≦ 0.5%, Cr ≦ 1%, Ni ≦ 1%.

[0030] When the above alloy components are present and the average ferrite crystal grain size is 200 μm or less, the yield strength of the ferrite-phase steel plate is less than 180 MPa, and the elongation is 30% or more.

[0031] In one embodiment of the present invention, the cross-section of the energy absorption structure in the core can have any type of axisymmetric geometric shape. Examples of the cross-sectional shape having any type of axisymmetric geometric shape mainly include a cross shape, an I shape, etc.

[0032] In one embodiment of the present invention, the energy absorption structure in the core of the axial steel damper can adopt a cross-sectional shape that is narrow in the middle and wide at both ends. As shown in FIGS. 2 and 3, FIG. 2 shows the geometric shapes and their relative positions of the ferrite-phase steel plate and the austenite-phase steel plate that constitute the energy absorption structure in the core. FIG. 3 is a schematic diagram of the corresponding energy absorption structure in the core formed by welding and assembly.

[0033] In the present invention, when the two types of steel plates have a geometric shape that is wide at both ends and narrow in the middle (the narrow part in the middle of the steel plate is called the core part of energy absorption), the narrow part in the middle of the energy absorption structure in the core composed of the two types of steel plates is called the core part of energy absorption of the energy absorption structure in the core. Since the axial steel damper is connected to the main structure of the building's columns and beams and other steel braces through joints and other connection components, the above-mentioned geometric design of the cross-section of the energy absorption structure in the core is such that the plastic deformation of the steel damper is concentrated only on the core part of energy absorption of the energy absorption structure in the core, and during the use of the axial steel damper, major yield deformation or even fracture of the joint or other connection components is avoided.

[0034] A reasonable selection of the ratio between the core part of energy absorption of the energy absorption structure in the core and the cross-sectional areas at both ends is mainly determined by the material strength of the energy absorption structure in the core and the joint or other connection components, and the connection strength between the two. In principle, when yielding occurs, the yield load of the joint or other connection components needs to be greater than the yield load of the energy absorption structure in the core.

[0035] The present invention further provides an axially steel damper including the energy absorption structure in the above core and its surrounding restraint components. The energy absorption structure in the core serves to absorb external vibration energy when the axially steel damper undergoes plastic deformation of expansion and contraction periodically and alternately. The surrounding restraint components suppress the lateral displacement of the energy absorption structure in the core and prevent the energy absorption structure in the core from buckling and becoming unstable.

[0036] In one embodiment of the present invention, the surrounding restraint components of the axially steel damper are selected from a restraint casing formed by a combination of a steel pipe and internally filled concrete, or a reinforced concrete restraint casing, or a pure steel structure restraint member.

[0037] The present invention further provides the use of the axially steel damper. The axially steel damper is used alone or in combination with other steel braces to form an axial energy absorption brace and is installed in a building or structure. It is connected to the main column-beam structure and joints of the building or structure to form an entirety and serves to absorb external vibration energy.

[0038] In one embodiment of the present invention, the axially steel damper can be connected to other steel braces via flanges or intermediate connecting plates to form an axial energy absorption brace in combination, meeting the requirements of prefabricated buildings and rapid replacement after earthquakes. The combined axial energy absorption brace is installed in a building or structure, connected to the main column-beam structure and joints of the building or structure to form an entirety, absorbs external vibration energy, and can significantly improve the seismic performance of the building or structure.

[0039] In one embodiment of the present invention, the axially steel damper is directly installed alone in a building or structure, connected to the main column-beam structure and joints of the building or structure to form an entirety, absorbs external vibration energy, and can significantly improve the seismic performance of the building or structure.

[0040] The structural size of the axial steel damper according to the present invention is generally smaller than that of the conventional buckling-restrained brace, and the self-weight is lighter. FIG. 4 is a schematic view of an axial energy-absorbing brace formed by combining an exchangeable axial steel damper and other steel braces, and its three-dimensional view is shown in FIG. 5. One end of the axial steel damper is connected to the building gusset plate through an intermediate connection plate and a spherical hinge, and the other end of the axial steel damper is connected to other steel braces through an intermediate connection plate (or flange) and combined to form an axial energy-absorbing brace.

[0041] According to the research of the present application, it can be seen that the fundamental reason for the low low-cycle fatigue performance of low-carbon ferrite steel is as follows. During repeated deformation, cross-slip occurs frequently, and the microscopic plastic deformation is irreversible, leading to a decrease in the tissue stability of the material and local concentration of plastic strain. As the cumulative strain of the cycle increases, fatigue cracks nucleate at the interfaces of the surface tissue of the material (for example, grain boundaries, ferrite / cementite phase boundaries) or slip regions, and grow along the grain boundaries or grow within the grains until intergranular fracture or intragranular fracture of the material occurs. Therefore, the ductility and cumulative plastic deformation capacity of steel dampers made of low-carbon ferrite steel (for example, LY225 and Q235) are low. The buckling-restrained brace made of Fe-Mn-Si alloy steel with low laminated defect energy has limitations in protecting the main structure of the building. The present invention develops an axial steel damper with a small yield displacement, excellent ductility and cumulative plastic deformation capacity, and the same redundancy as the main structure of the building to become invalid.

[0042] Compared with the prior art, the beneficial effects of the present invention are as follows.

[0043] 1) Compared with the conventional buckling-restrained brace (the energy absorption structure in the core is usually made of LY225 or Q235 steel plate), the energy absorption structure in the core of the axial steel damper of the present invention has excellent ductility and cumulative plastic deformation ability, the ratio of its ultimate allowable displacement to the yield displacement is 10 or more, the ultimate allowable displacement is 1 / 60 or more of the axial length of the steel damper, and under the condition of this ultimate allowable displacement, the axial steel damper can complete at least 30 cycles of alternating plastic deformation of tension and compression, and the reduction of the load capacity is less than 15%. The conventional buckling-restrained brace cannot achieve the above index performance. 2) Compared with the buckling-restrained brace made of Fe-Mn-Si austenitic alloy steel with low laminated defect energy that may be used, the energy absorption structure in the core of the axial steel damper according to the present invention has a small yield displacement and yield load, a low work hardening degree, excellent ductility, and low cost. According to the applicant's research, the buckling-restrained brace made of Fe-Mn-Si austenitic alloy steel with low laminated defect energy has a large yield load and yield displacement, so in many cases the ratio of its ultimate allowable displacement to the yield displacement is less than 7, which shows that the energy absorption effect of the brace is not significant. Furthermore, the cost of Fe-Mn-Si austenitic alloy steel with low laminated defect energy is relatively high, and the cost of the buckling-restrained brace made only of this type of material is also high. 3) Compared with the conventional buckling-restrained brace and the buckling-restrained brace made of Fe-Mn-Si austenitic alloy steel with low laminated defect energy that may be used, the axial steel damper according to the present invention has a significantly improved ductility, can achieve yield and energy absorption in earthquakes of different seismic intensities, becomes invalid with the same redundancy as the main structure of the building, and has excellent cumulative plastic deformation ability. 4) The axial steel damper according to the present invention can be connected and combined with other steel braces to form an axial energy absorption brace, meeting the requirements of prefabricated buildings and rapid replacement after an earthquake. The structural size and self-weight of the axial steel damper according to the present invention can be made smaller than the structural size and self-weight of the conventional buckling-restrained brace. 5) Conventional buckling restraint braces need to be designed and manufactured according to the diagonal dimensions of the main structural frame. However, the size of the energy absorption brace components is generally large and not suitable for on-site installation and post-earthquake replacement. The structural size of the axial steel damper according to the present invention is generally smaller than that of the conventional buckling restraint brace, with a lighter self-weight, and is easy for on-site installation and post-earthquake replacement.

[0044] In the present invention, for the steel plate of the austenite phase that constitutes the energy absorption structure in the core of the axial steel damper, during the alternating plastic deformation of tension and compression, a reversible phase transformation occurs between austenite and strain-induced ε-martensite. Therefore, the steel plate of the austenite phase has excellent fatigue deformation performance, and thereby, the axial steel damper can have a very high allowable displacement limit. When only the deformation of slip on the plane of rotation occurs under repeated loading for the steel plate of the austenite phase used in the energy absorption structure in the core of the axial steel damper, the mass fraction of the chemical components of the corresponding steel plate of the austenite phase may be 0.4% ≤ C ≤ 0.7%, 16.0% ≤ Mn ≤ 26.0%, Si ≤ 2.0%, P ≤ 0.02%, S ≤ 0.03%, N ≤ 0.03%, and the balance is Fe and inevitable impurity elements. The ductility and cumulative plastic deformation ability of the axial steel damper can be superior to those of the conventional buckling restraint brace, but are significantly lower than those of the axial steel damper of the present invention.

Brief Description of the Drawings

[0045]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Embodiments for Carrying Out the Invention

[0046] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings and specific embodiments.

[0047] (Example 1) An axial steel damper, which is composed of an energy absorption structure in the core and a surrounding restraint component.

[0048] The cross-section of the energy absorption structure in the core has a cruciform axisymmetric geometric shape with the axial direction of the steel damper as the axis of symmetry, being narrow in the center along the axial direction and wide at both ends. As shown in FIGS. 2 and 3, the energy absorption structure in the core is composed of one austenite-phase steel plate 2 and two ferrite-phase steel plates 1. The austenite-phase steel plate 2 and the ferrite-phase steel plates 1 have the same length along the longitudinal direction. With the center line in the longitudinal direction of the austenite-phase steel plate 2 as the axis of symmetry, the two ferrite-phase steel plates 1 are respectively arranged above and below the austenite-phase steel plate 2, and the two ferrite-phase steel plates 1 are respectively connected in close contact with the austenite-phase steel plate 2 by welding. The weld seam 3 is parallel to the axial direction of the energy absorption structure in the core and the steel damper. In FIG. 2, the two side surfaces of the ferrite-phase steel plate 1 are the welding side 11 and the non-welding side 12 respectively.

[0049] The geometric shape of the austenite-phase steel plate constituting the energy absorption structure in the core is shown in FIG. 6. The total length of the austenite-phase steel plate is L = 2000 mm, the length of the central part (the core part of energy absorption) of the steel plate is L0 = 1530 mm, the width is W0 = 160 mm, and the thickness of the steel plate is T = 16 mm.

[0050] The chemical composition and its mass fraction of the austenite-phase steel plate are 29.4% Mn, 4.3% Si, 1.4% Al, 0.049% C, 0.009% P, 0.008% S, 0.005% N, and the balance is Fe and inevitable impurity elements. The yield strength of the austenite-phase steel plate is 304 MPa, and the elongation is 52%. The microstructure of the austenite-phase steel plate is a single austenite structure, the average austenite crystal grain size is 76 μm. When entering the yield stage, metastable austenite undergoes ε-martensite phase transformation due to the action of strain, and the α'-martensite phase transformation is suppressed. Under the action of repeated tensile and compressive loads, a reversible phase transformation occurs between metastable austenite and strain-induced ε-martensite.

[0051] The geometric shape of the ferrite-phase steel plate constituting the energy absorption structure in the core is shown in Fig. 7. The total length of the ferrite-phase steel plate is l = 2000 mm, the length of the central part (the core part of energy absorption) of the steel plate is l0 = 1530 mm, the width is w0 / 2 = 80 mm, and the thickness of the steel plate is t = 16 mm.

[0052] The chemical composition and its mass fraction of the ferrite-phase steel plate are 0.30% Mn, 0.05% Si, 0.015% C, 0.05% Ti, 0.012% P, 0.006% S, 0.006% N, and the balance is Fe and inevitable impurity elements. The yield strength of the ferrite-phase steel plate is 157 MPa, and the elongation is 47%. The microstructure of the ferrite-phase steel plate is mainly ferrite structure, and the average ferrite crystal grain size is 50 μm.

[0053] The thickness of the steel plate of the austenite phase is the same as the thickness of the steel plate of the ferrite phase. The ratio of the sum of the cross-sectional areas of the core portions of the energy absorption of the two ferrite-phase steel plates to the cross-sectional area of the core portion of the energy absorption of one austenite-phase steel plate is 1.0 (greater than 0.6). After being assembled by welding, the distance from the welding seam for connection between the ferrite-phase steel plate and the austenite-phase steel plate to the non-welded side of the core portion of the energy absorption of the two ferrite-phase steel plates (that is, the width w0 / 2 of the core portion of the energy absorption of the ferrite-phase steel plate) and the thickness (t) of the ferrite-phase steel plate are both 5.0.

[0054] The front view, top view, and side view of the energy absorption structure in the core after being assembled by welding are shown in FIGS. 8, 9, and 10 respectively.

[0055] The peripheral restraint component is a restraint casing formed by combining a peripheral restraint steel pipe 4 and an internal filled concrete 9, which plays a role in restraining the lateral displacement of the energy absorption structure in the core and preventing the buckling of the energy absorption structure in the core. In order to remove the friction between the peripheral restraint component and the energy absorption structure in the core, a non-bonding material layer is provided between the peripheral restraint component and the energy absorption structure in the core.

[0056] The front view, top view, and cross-sectional view along plane A-A of the assembled axial steel damper are shown in FIGS. 11, 12, and 13 respectively.

[0057] Figure 14 shows the repeated stress-strain curve when the axial steel damper alternately undergoes tension and compression deformation. After 33 cycles of periodic alternation of tension and compression are applied to the axial steel damper at a displacement of 40 mm, fatigue failure does not occur and the maximum load capacity hardly changes. The 40-mm operating displacement corresponds to 1 / 50 of the axial length of the steel damper. From Figure 14, it can be seen that the limit allowable displacement of the axial steel damper is greater than 40 mm. The elastic rigidity is obtained from the unloading part of the repeated stress-strain curve at a 40-mm displacement, and the yield displacement is obtained to be approximately 3.1 mm. Subsequently, repeated deformation is continued for 2 cycles at a displacement of 43 mm. From the deformation repeated stress-strain curve, it can be seen that the deformation displacement increases with the tension-compression cycle, but the yield displacement hardly changes. The ratio (i.e., ductility) of the calculated limit allowable displacement to the yield displacement of the axial steel damper is greater than 12.9.

[0058] Therefore, the ratio of the limit allowable displacement to the yield displacement of the axial steel damper according to this embodiment is greater than 10, and the limit allowable displacement is greater than 1 / 60 of the axial length of the steel damper. Under the condition of this limit allowable displacement, the axial steel damper can complete at least 30 cycles of alternating plastic deformation of tension and compression, and the reduction in load capacity is less than 15%. The axial steel damper in this embodiment can achieve the same redundancy as the main structure of the building and become invalid.

[0059] Figures 4 and 5 are schematic diagrams of an axial energy absorption brace formed by combining the axial steel damper in this embodiment with other steel braces. One end of the axial steel damper 5 is connected to the building gusset plate via an intermediate connection plate 6 and a spherical hinge 8, and the other end of the axial steel damper 5 is connected to another steel brace 7 via the intermediate connection plate 6 and combined to form an axial energy absorption brace.

[0060] (Example 2) An axial steel damper, which is composed of an energy absorption structure in the core and a surrounding restraint component.

[0061] The cross-section of the energy absorption structure in the core has a cruciform axisymmetric geometric shape with the axial direction of the steel damper as the axis of symmetry, being narrow in the center and wide at both ends along the axial direction. Specifically, the energy absorption structure in the core is composed of one austenite-phase steel plate and two ferrite-phase steel plates. The austenite-phase steel plate and the ferrite-phase steel plate have the same length in the longitudinal direction. The relative positions and connection methods of the two types of steel plates are shown in FIGS. 2 and 3.

[0062] The geometric shape of the austenite-phase steel plate constituting the energy absorption structure in the core is shown in FIG. 6. The total length of the austenite-phase steel plate is L = 2000 mm, the length of the central part (the core part of energy absorption) of the steel plate is L0 = 1530 mm, the width is W0 = 50 mm, and the thickness of the steel plate is T = 16 mm.

[0063] The chemical composition and its mass fraction of the austenite-phase steel plate are 29.4% Mn, 4.3% Si, 1.4% Al, 0.049% C, 0.009% P, 0.008% S, 0.005% N, and the balance is Fe and inevitable impurity elements. The yield strength of the austenite-phase steel plate is 304 MPa, and the elongation is 52%. The microstructure of the austenite-phase steel plate is a single austenite structure, the average austenite crystal grain size is 76 μm. When entering the yield stage, metastable austenite undergoes ε-martensite phase transformation due to the action of strain. Under the action of repeated tensile and compressive loads, a reversible phase transformation occurs between metastable austenite and strain-induced ε-martensite.

[0064] The geometric shape of the ferrite-phase steel plate constituting the energy absorption structure in the core is shown in FIG. 7. The total length of the ferrite-phase steel plate is l = 2000 mm, the length of the central part (the core part of energy absorption) of the steel plate is l0 = 1530 mm, the width is w0 / 2 = 80 mm, and the thickness of the steel plate is t = 16 mm.

[0065] The chemical composition and mass fraction of the ferrite-phase steel plate are 0.30% Mn, 0.05% Si, 0.015% C, 0.05% Ti, 0.012% P, 0.006% S, and 0.006% N, with the balance being Fe and inevitable impurity elements. The yield strength of the ferrite-phase steel plate is 157 MPa, and the elongation is 47%. The microstructure of the ferrite-phase steel plate is mainly ferrite, and the average ferrite crystal grain size is 50 μm.

[0066] The thickness of the austenite-phase steel plate is the same as that of the ferrite-phase steel plate. The ratio of the total cross-sectional area of the energy absorption core parts of two ferrite-phase steel plates to the cross-sectional area of the energy absorption core part of one austenite-phase steel plate is 3.2 (greater than 0.6). After being welded and assembled, the ratio of the distance from the welding seam for connection between the ferrite-phase steel plate and the austenite-phase steel plate to the non-welded side of the energy absorption core part of the two ferrite-phase steel plates (i.e., the width w0 / 2 of the energy absorption core part of the ferrite-phase steel plate) to the thickness (t) of the ferrite-phase steel plate is both 5.0.

[0067] The surrounding restraint component is a restraint casing formed by combining a steel pipe and internally filled concrete. A non-bonding material layer is provided between the surrounding restraint component and the energy absorption structure in the core.

[0068] Figure 15 is the repeated stress-strain curve when the axial steel damper is periodically and alternately subjected to tensile and compressive plastic deformations. After the axial steel damper is subjected to 30 cycles of periodic alternation of tension and compression at a displacement of 40 mm, 4 cycles of alternation of tension and compression are applied at a displacement of 45 mm, and no fatigue failure occurs and the loading capacity does not decrease. The operating displacement of 40 mm corresponds to 1 / 50 of the axial length of the steel damper. The limit allowable displacement of the axial steel damper is greater than 40 mm. The elastic stiffness is obtained from the unloading part of the repeated stress-strain curve at a displacement of 40 mm, and the yield displacement is obtained to be about 3.1 mm (comparing the repeated stress-strain curves of the deformation displacement of 40 mm and the deformation displacement of 45 mm, it can be seen that after the deformation displacement of 40 mm, the deformation displacement increases with the tensile-compression cycle, and the yield displacement does not change much). The ratio (i.e., ductility) of the calculated limit allowable displacement to the yield displacement of the axial steel damper is greater than 12.9.

[0069] Therefore, the ratio of the limit allowable displacement to the yield displacement of the axial steel damper according to this embodiment is greater than 10, and the limit allowable displacement is greater than 1 / 60 of the axial length of the steel damper. Under the condition of this limit allowable displacement, the axial steel damper can complete at least 30 cycles of periodic alternating plastic deformations of tension and compression, and the decrease in the loading capacity is less than 15%. The axial steel damper in this embodiment can achieve the same redundancy as the main structure of the building and become ineffective.

[0070] (Example 3) An axial steel damper, which is composed of an energy absorption structure in the core and a surrounding restraint component.

[0071] The cross-section of the energy absorption structure in the core has a cruciform axisymmetric geometric shape with the axial direction of the steel damper as the axis of symmetry, being narrow in the center and wide at both ends along the axial direction. Specifically, the energy absorption structure in the core is composed of one austenite-phase steel plate and two ferrite-phase steel plates. The austenite-phase steel plate and the ferrite-phase steel plate have the same length in the longitudinal direction. The relative positions and connection methods of the two types of steel plates are shown in FIGS. 2 and 3.

[0072] The geometric shape of the austenite-phase steel plate constituting the energy absorption structure in the core is shown in FIG. 6. The total length of the austenite-phase steel plate is L = 2000 mm, the length of the central part (the core part for energy absorption) of the steel plate is L0 = 1530 mm, the width is W0 = 160 mm, and the thickness of the steel plate is T = 14 mm.

[0073] The chemical composition and its mass fraction of the austenite-phase steel plate are 27.5% Mn, 4.0% Si, 0.6% Al, 0.002% C, 2.0% Ni, 0.7% Cu, 0.007% P, 0.006% S, 0.005% N, and the balance is Fe and inevitable impurity elements. The yield strength of the austenite-phase steel plate is 229 MPa, and the elongation is 58%. The microstructure of the austenite-phase steel plate is a single austenite structure, and the average austenite crystal grain size is 126 μm. When entering the yield stage, metastable austenite undergoes ε-martensite phase transformation under the action of strain. Under the action of repeated tensile and compressive loads, a reversible phase transformation occurs between metastable austenite and strain-induced ε-martensite.

[0074] The geometric shape of the ferrite-phase steel plate constituting the energy absorption structure in the core is shown in FIG. 7. The total length of the ferrite-phase steel plate is l = 2000 mm, the length of the central part (the core part for energy absorption) of the steel plate is l0 = 1530 mm, the width is w0 / 2 = 200 mm, and the thickness of the steel plate is t = 16 mm.

[0075] The chemical composition and mass fraction of the ferrite-phase steel plate are 0.18% Mn, 0.05% Si, 0.01% C, 0.04% Ti, 0.01% P, 0.006% S, and 0.006% N, with the balance being Fe and inevitable impurity elements. The yield strength of the ferrite-phase steel plate is 122 MPa, and the elongation is 50%. The microstructure of the ferrite-phase steel plate is mainly ferrite, and the average ferrite crystal grain size is 86 μm.

[0076] The thickness of the austenite-phase steel plate is 0.875 times the thickness of the ferrite-phase steel plate. The ratio of the sum of the cross-sectional areas of the core parts of the energy absorption of two ferrite-phase steel plates to the cross-sectional area of the core part of the energy absorption of one austenite-phase steel plate is 2.86 (greater than 0.6). After being welded and assembled, the ratio of the distance from the welding seam for connection between the ferrite-phase steel plate and the austenite-phase steel plate to the non-welded side of the core part of the energy absorption of the two ferrite-phase steel plates (i.e., the width w0 / 2 of the core part of the energy absorption of the ferrite-phase steel plate) to the thickness (t) of the ferrite-phase steel plate is 12.5 in both cases.

[0077] The peripheral restraint component is a restraint casing formed by combining a steel pipe and internally filled concrete. A non-bonding material layer is provided between the peripheral restraint component and the energy absorption structure in the core.

[0078] After axial steel dampers are subjected to 30 cycles of periodic alternation of tension and compression at a displacement of 40.4 mm, no fatigue failure occurs and the loading capacity does not decrease. The operating displacement of 40.4 mm corresponds to 1 / 50 of the axial length of the steel damper. The ultimate allowable displacement of the axial steel damper is greater than 40.4 mm. The yield displacement obtained from the repeated stress-strain curve is approximately 3.1 mm. The ratio of the calculated ultimate allowable displacement to the yield displacement of the axial steel damper (i.e., ductility) is greater than 13.

[0079] Therefore, the ratio of the ultimate allowable displacement to the yield displacement of the axial steel damper in this embodiment is greater than 10, and the ultimate allowable displacement is greater than 1 / 60 of the axial length of the steel damper. Under the condition of this ultimate allowable displacement, the axial steel damper can complete at least 30 cycles of alternating plastic deformation of tension and compression, and the reduction of the loading capacity is less than 15%.

[0080] (Example 4) An axial steel damper, which is composed of an energy absorption structure in the core and a surrounding restraint component.

[0081] The cross-section of the energy absorption structure in the core has a cruciform axisymmetric geometric shape with the axial direction of the steel damper as the axis of symmetry, being narrow in the center and wide at both ends along the axial direction. Specifically, the energy absorption structure in the core is composed of one austenite-phase steel plate and two ferrite-phase steel plates. The austenite-phase steel plate and the ferrite-phase steel plate have the same longitudinal length. The relative positions and connection methods of the two types of steel plates are shown in FIGS. 2 and 3.

[0082] The geometric shape of the austenite-phase steel plate constituting the energy absorption structure in the core is shown in FIG. 6. The total length of the austenite-phase steel plate is L = 2000 mm, the length of the central part (the core part of energy absorption) of the steel plate is L0 = 1530 mm, the width is W0 = 160 mm, and the thickness of the steel plate is T = 5 mm.

[0083] The chemical composition and its mass fraction of the steel plate of the austenite phase are 26.3% Mn, 4.1% Si, 1.0% Al, 1.1% Ni, 0.02% C, 0.009% P, 0.008% S, 0.005% N, and the balance is Fe and inevitable impurity elements. The yield strength of the steel plate of the austenite phase is 288 MPa, and the elongation is 50%. The microstructure of the steel plate of the austenite phase is a single austenite structure, and the average austenite crystal grain size is 102 μm. When entering the yield stage, metastable austenite undergoes ε-martensite phase transformation due to the action of strain. Under the action of repeated tensile and compressive loads, a reversible phase transformation occurs between metastable austenite and strain-induced ε-martensite.

[0084] The geometric shape of the steel plate of the ferrite phase constituting the energy absorption structure in the core is shown in Fig. 7. The total length of the steel plate of the ferrite phase is l = 2000 mm, the length of the central part (the core part of energy absorption) of the steel plate is l0 = 1530 mm, the width is w0 / 2 = 290 mm, and the thickness of the steel plate is t = 12 mm.

[0085] The chemical composition and its mass fraction of the steel plate of the ferrite phase are 0.50% Mn, 0.3% Si, 0.095% C, 0.1% Ti, 0.06% Nb, 0.01% P, 0.006% S, 0.005% N, and the balance is Fe and inevitable impurity elements. The yield strength of the steel plate of the ferrite phase is 175 MPa, and the elongation is 31.5%. The microstructure of the steel plate of the ferrite phase is mainly ferrite, and the average ferrite crystal grain size is 192 μm.

[0086] The thickness of the austenite-phase steel plate is 0.416 times the thickness of the ferrite-phase steel plate. The ratio of the sum of the cross-sectional areas of the core parts of the energy absorption of two ferrite-phase steel plates to the cross-sectional area of the core part of the energy absorption of one austenite-phase steel plate is 8.7 (greater than 0.6). After being assembled by welding, the distance from the welding seam for connection between the ferrite-phase steel plate and the austenite-phase steel plate to the non-welded side of the core part of the energy absorption of the two ferrite-phase steel plates (i.e., the width w0 / 2 of the core part of the energy absorption of the ferrite-phase steel plate) and the ratio of the thickness (t) of the ferrite-phase steel plate are both 24.2.

[0087] The peripheral restraint component is a restraint casing formed by combining a steel pipe and internally filled concrete. A non-bonding material layer is provided between the peripheral restraint component and the energy absorption structure in the core.

[0088] The axial steel damper does not undergo fatigue failure and its loading capacity does not decrease after 30 cycles of periodic alternation of tension and compression are applied at a displacement of 33.8 mm. The operating displacement of 33.8 mm corresponds to 1 / 60 of the axial length of the steel damper. The ultimate allowable displacement of the axial steel damper is greater than 33.8 mm. The elastic rigidity is obtained from the unloading part of the repeated stress-strain curve, and the yield displacement is obtained to be approximately 3.0 mm. The ratio of the calculated ultimate allowable displacement to the yield displacement of the axial steel damper (i.e., ductility) is greater than 11.2.

[0089] Therefore, in this embodiment, the ratio of the ultimate allowable displacement to the yield displacement of the axial steel damper is greater than 10, and the ultimate allowable displacement is greater than 1 / 60 of the axial length of the steel damper. Under the condition of this ultimate allowable displacement, the axial steel damper can complete at least 30 cycles of periodic alternating plastic deformation of tension and compression, and the decrease in the loading capacity is less than 15%.

[0090] (Examples 5 to 8) An axial steel damper, which is composed of an energy absorption structure in the core and a surrounding restraint component.

[0091] The energy absorption structure in the core is composed of a single austenite-phase steel plate and a single ferrite-phase steel plate. The austenite-phase steel plate and the ferrite-phase steel plate have the same length in the longitudinal direction. The ferrite-phase steel plate is arranged perpendicular to the austenite-phase steel plate, and the ferrite-phase steel plate and the austenite-phase steel plate are closely connected by welding. The weld seam is parallel to the axial direction of the axial steel damper, and the connecting weld seam is located on the austenite-phase steel plate.

[0092] The geometric shape of the austenite-phase steel plate constituting the energy absorption structure in the core is shown in Fig. 6. The total length of the austenite-phase steel plate is L = 2000 mm, the length of the central part (the core part of energy absorption) of the steel plate is L0 = 1530 mm, the width is W0 = 80 mm, and the thickness of the steel plate is T = 16 mm.

[0093] The geometric shape of the ferrite-phase steel plate constituting the energy absorption structure in the core is shown in Fig. 7. The total length of the ferrite-phase steel plate is l = 2000 mm, the length of the central part (the core part of energy absorption) of the steel plate is l0 = 1530 mm, the width is w0 / 2 = 80 mm, and the thickness of the steel plate is t = 16 mm.

[0094] The thickness of the austenite-phase steel plate is the same as that of the ferrite-phase steel plate. The ratio of the cross-sectional area of the core part of energy absorption of the ferrite-phase steel plate to the cross-sectional area of the core part of energy absorption of the austenite-phase steel plate is 1.0 (greater than 0.6). After being welded and assembled, the ratio of the distance from the connecting weld seam between the ferrite-phase steel plate and the austenite-phase steel plate to the non-welded side of the core part of energy absorption of the ferrite-phase steel plate (i.e., the width w0 / 2 of the core part of energy absorption of the ferrite-phase steel plate) to the thickness (t) of the ferrite-phase steel plate is 5.0.

[0095] Table 1 shows the main chemical components of the austenite-phase steel sheet (the steel unavoidably contains trace amounts of P, S, N, and other impurity elements) and its mechanical properties. The microstructure of the austenite-phase steel sheet is a single austenite structure. When entering the yield stage, metastable austenite undergoes ε-martensite phase transformation due to the action of strain. Under the action of repeated tensile and compressive loads, a reversible phase transformation occurs between metastable austenite and strain-induced ε-martensite. Table 1 shows the average austenite crystal grain size of the austenite-phase steel sheet.

[0096] Table 1 shows the main chemical components of the ferrite-phase steel sheet (the steel unavoidably contains trace amounts of P, S, N, and other impurity elements) and its mechanical properties. The microstructure of the ferrite-phase steel sheet is mainly a ferrite structure. Table 1 shows the average ferrite crystal grain size of the ferrite-phase steel sheet.

Table 1

[0097] The surrounding restraint component is a restraint casing formed by combining a steel pipe and internally filled concrete. A non-bonding material layer is provided between the surrounding restraint component and the energy absorption structure in the core.

[0098] In the above embodiment, Table 2 shows the yield displacement, ultimate allowable displacement, and the ratio of the ultimate allowable displacement to the yield displacement of the axial steel damper. Under the condition of this ultimate allowable displacement, all of the axial steel dampers complete at least 30 cycles of repeated plastic deformation of tension and compression, no fatigue failure occurs, and the loading capacity of the steel damper does not decrease.

Table 2

[0099] Therefore, in the above embodiments, the ratios of the limit allowable displacement to the yield displacement of the axial steel dampers are all greater than 10, and the limit allowable displacement is greater than 1 / 60 of the axial length of the steel damper. Under the condition of this limit allowable displacement, the axial steel damper can complete at least 30 cycles of alternating plastic deformation of tension and compression, and the reduction of the loading capacity is less than 15%.

[0100] (Example 9) An axial steel damper, which is composed of an energy absorption structure in the core and a surrounding restraint component.

[0101] The energy absorption structure in the core is composed of a single austenite-phase steel plate and a single ferrite-phase steel plate. The austenite-phase steel plate and the ferrite-phase steel plate have the same longitudinal length. The ferrite-phase steel plate is arranged perpendicular to the austenite-phase steel plate. The ferrite-phase steel plate and the austenite-phase steel plate are closely connected by welding. The weld seam is parallel to the axial direction of the axial steel damper, and the connecting weld seam is located on the austenite-phase steel plate.

[0102] The geometric shape of the austenite-phase steel plate constituting the energy absorption structure in the core is shown in FIG. 6. The total length of the austenite-phase steel plate is L = 2000 mm, the length of the central part of the steel plate (i.e., the core part of energy absorption) is L0 = 1530 mm, the width is W0 = 100 mm, and the thickness of the steel plate is T = 16 mm.

[0103] The geometric shape of the ferrite-phase steel plate constituting the energy absorption structure in the core is shown in FIG. 7. The total length of the ferrite-phase steel plate is l = 2000 mm, the length of the central part of the steel plate (i.e., the core part of energy absorption) is l0 = 1530 mm, the width is w0 / 2 = 65 mm, and the thickness of the steel plate is t = 16 mm.

[0104] The thickness of the austenite-phase steel sheet is the same as that of the ferrite-phase steel sheet. The ratio of the cross-sectional area of the core part of the energy absorption of the ferrite-phase steel sheet to the cross-sectional area of the core part of the energy absorption of the austenite-phase steel sheet is 0.65 (greater than 0.6). After being welded and assembled, the distance from the welding seam for connection between the ferrite-phase steel sheet and the austenite-phase steel sheet to the non-welded side of the core part of the energy absorption of the ferrite-phase steel sheet (i.e., the width w0 / 2 of the core part of the energy absorption of the ferrite-phase steel sheet) and the ratio of the thickness (t) of the ferrite-phase steel sheet are approximately 4.1.

[0105] The chemical composition and its mass fraction of the austenite-phase steel sheet are 29.4% Mn, 4.3% Si, 1.4% Al, 0.049% C, 0.009% P, 0.008% S, 0.005% N, and the balance is Fe and inevitable impurity elements. The average austenite crystal grain size of the austenite-phase steel sheet is 76 μm. The yield strength of the austenite-phase steel sheet is 304 MPa, and the elongation is 52%. The microstructure of the austenite-phase steel sheet is a single austenite structure. When entering the yield stage, metastable austenite undergoes ε-martensite phase transformation due to the action of strain, and the α'-martensite phase transformation is suppressed. Under the action of repeated tensile and compressive loads, a reversible phase transformation occurs between metastable austenite and strain-induced ε-martensite.

[0106] The chemical composition and its mass fraction of the ferrite-phase steel sheet are 0.30% Mn, 0.05% Si, 0.015% C, 0.05% Ti, 0.012% P, 0.006% S, 0.006% N, and the balance is Fe and inevitable impurity elements. The yield strength of the ferrite-phase steel sheet is 157 MPa, and the elongation is 47%. The microstructure of the ferrite-phase steel sheet is mainly ferrite, and the average ferrite crystal grain size is 50 μm.

[0107] The surrounding restraint component is a restraint casing formed by combining a steel pipe and internally filled concrete. In order to remove the friction between the surrounding restraint component and the energy absorption structure in the core, a non-bonding material layer is provided between the surrounding restraint component and the energy absorption structure in the core.

[0108] After axial steel dampers are subjected to 30 cycles of periodic alternation of tension and compression at a displacement of 40 mm, no fatigue failure occurs and the loading capacity also does not decrease. The operating displacement of 40 mm corresponds to 1 / 50 of the total length of the steel damper. The limit allowable displacement of the axial steel damper is greater than 40 mm. From the repeated stress-strain curve at a displacement of 40 mm, the yield displacement is obtained and is approximately 3.8 mm. The ratio (i.e., ductility) of the calculated limit allowable displacement to the yield displacement of the axial steel damper is greater than 10.5.

[0109] Therefore, in this embodiment, the ratio of the limit allowable displacement to the yield displacement of the axial steel damper is greater than 10, and the limit allowable displacement is greater than 1 / 60 of the axial length of the steel damper. Under the condition of this limit allowable displacement, the axial steel damper can complete at least 30 cycles of alternating plastic deformation of tension and compression, and the decrease in the loading capacity is less than 15%.

[0110] (Comparative Example 1) A buckling restraint brace composed of an energy absorption structure in the core and a surrounding restraint component.

[0111] The cross-section of the energy absorption structure in the core has a cruciform axisymmetric geometric shape with the axial direction of the energy absorption brace as the axis of symmetry, being narrow in the center and wide at both ends along the axial direction. Specifically, the energy absorption structure in the core is composed of one wide austenitic steel plate and two narrow austenitic steel plates. The three austenitic steel plates have the same length in the longitudinal direction. With the center line in the longitudinal direction of the wide austenitic steel plate as the axis of symmetry, the two narrow austenitic steel plates are respectively provided above and below the wide austenitic steel plate. The three austenitic steel plates are closely connected by welding, and the weld seams are parallel to the axial direction of the buckling restraint brace.

[0112] The geometric shape of the wide austenitic steel plate is shown in Fig. 6. The total length of the wide austenitic steel plate is L = 2000 mm, the length of the central part of the steel plate is L0 = 1530 mm, the width is W0 = 160 mm, and the thickness of the steel plate is T = 16 mm.

[0113] The geometric shape of the narrow austenitic steel plate is shown in Fig. 7. The total length of the narrow austenitic steel plate is l = 2000 mm, the length of the central part of the steel plate is l0 = 1530 mm, the width is w0 / 2 = 80 mm, and the thickness of the steel plate is t = 16 mm.

[0114] The chemical compositions of the wide and narrow austenitic steel plates are exactly the same. The mass fractions of its chemical composition are 29.4% Mn, 4.3% Si, 1.4% Al, 0.049% C, 0.009% P, 0.008% S, 0.005% N, and the balance is Fe and inevitable impurity elements. The yield strength of the austenitic steel plate is 304 MPa, and the elongation is 52%. The microstructure of the austenitic steel plate is a single austenite structure, the average austenite crystal grain size is 76 μm. When entering the yield stage, metastable austenite undergoes ε-martensite phase transformation under the action of strain. Under the action of repeated tensile and compressive loads, a reversible phase transformation occurs between metastable austenite and strain-induced ε-martensite.

[0115] The surrounding restraint component is a restraint casing formed by combining a steel pipe and internally filled concrete. A non-bonding material layer is provided between the surrounding restraint component and the energy absorption structure in the core.

[0116] For the buckling restraint brace, tension and compression are periodically applied alternately about 30 cycles with a displacement of 51.4 mm, resulting in fatigue failure (during fatigue deformation, the maximum load capacity basically does not change). The operating displacement of 51.4 mm corresponds to 1 / 39 of the total length of the brace. The limit allowable displacement of the buckling restraint brace is about 51.4 mm. The yield displacement obtained from the repeated stress-strain curve is about 7.8 mm. The ratio of the limit allowable displacement to the yield displacement (i.e., ductility) of the buckling restraint brace is calculated to be about 6.6.

[0117] Therefore, although the buckling restraint brace described in this comparative example has a larger limit allowable displacement, its yield displacement is also large, so the ratio of the limit allowable displacement to the yield displacement is much less than 10.

[0118] (Comparative Example 2) A buckling restraint brace composed of an energy absorption structure in the core and a surrounding restraint component.

[0119] The cross-section of the energy absorption structure in the core has a cruciform axisymmetric geometric shape with the axial direction of the steel damper as the axis of symmetry, being narrow in the center along the axial direction and wide at both ends. Specifically, the energy absorption structure in the core is composed of one wide ferrite-phase steel plate and two narrow ferrite-phase steel plates. The three ferrite-phase steel plates have the same longitudinal length. With the center line in the longitudinal direction of the wide ferrite-phase steel plate as the axis of symmetry, the two narrow ferrite-phase steel plates are respectively arranged above and below the wide ferrite-phase steel plate. The three ferrite-phase steel plates are closely connected by welding, and the weld seams are parallel to the axial direction of the buckling restraint brace.

[0120] The geometric shape of the wide ferrite phase steel plate is shown in Fig. 6. The total length of the wide ferrite phase steel plate is L = 2000 mm, the length of the central part of the steel plate is L0 = 1530 mm, the width is W0 = 160 mm, and the thickness of the steel plate is T = 16 mm.

[0121] The geometric shape of the narrow ferrite phase steel plate is shown in Fig. 7. The total length of the narrow ferrite phase steel plate is l = 2000 mm, the length of the central part of the steel plate is l0 = 1530 mm, the width is w0 / 2 = 80 mm, and the thickness of the steel plate is t = 16 mm.

[0122] The chemical compositions of the wide and narrow ferrite phase steel plates are exactly the same. The mass fractions of the chemical compositions are 0.30% Mn, 0.05% Si, 0.015% C, 0.05% Ti, 0.012% P, 0.006% S, 0.006% N, and the balance is Fe and inevitable impurity elements. The yield strength of the ferrite phase steel plate is 157 MPa, and the elongation is 47%. The microstructure of the ferrite phase steel plate is mainly ferrite tissue, and the average ferrite crystal grain size is 50 μm.

[0123] The peripheral restraint component is a restraint casing formed by combining a steel pipe and internally filled concrete. A non-bonding material layer is provided between the peripheral restraint component and the energy absorption structure in the core.

[0124] The buckling restraint brace is subjected to alternating stretching and compression at a displacement of 33 mm, and fatigue failure occurs in less than 30 cycles. The operating displacement of 33 mm corresponds to approximately 1 / 60 of the total length of the brace. Therefore, the limit allowable displacement of the buckling restraint brace in this comparative example is less than 33 mm, that is, less than 1 / 60 of the axial length of the energy absorption structure in the core.

[0125] (Comparative Example 3) An axial steel damper composed of an energy absorption structure in the core and a peripheral restraint component.

[0126] The energy absorption structure in the core is composed of a single austenite-phase steel plate and a single ferrite-phase steel plate. The austenite-phase steel plate and the ferrite-phase steel plate have the same length in the longitudinal direction. The ferrite-phase steel plate is arranged perpendicular to the austenite-phase steel plate. The ferrite-phase steel plate and the austenite-phase steel plate are closely connected by welding. The welding seam is parallel to the axial direction of the axial steel damper, and the connecting weld seam is located on the austenite-phase steel plate.

[0127] The geometric shape of the austenite-phase steel plate constituting the energy absorption structure in the core is shown in Fig. 6. The total length of the austenite-phase steel plate is L = 2000 mm, the length of the central part of the steel plate (i.e., the core part of energy absorption) is L0 = 1530 mm, the width is W0 = 100 mm, and the thickness of the steel plate is T = 16 mm.

[0128] The geometric shape of the ferrite-phase steel plate constituting the energy absorption structure in the core is shown in Fig. 7. The total length of the ferrite-phase steel plate is l = 2000 mm, the length of the central part of the steel plate (i.e., the core part of energy absorption) is l0 = 1530 mm, the width is w0 / 2 = 54 mm, and the thickness of the steel plate is t = 16 mm.

[0129] The thickness of the austenite-phase steel plate is the same as that of the ferrite-phase steel plate. The ratio of the cross-sectional area of the core part of energy absorption of the ferrite-phase steel plate to the cross-sectional area of the core part of energy absorption of the austenite-phase steel plate is 0.54 (less than 0.6). After being welded and assembled, the ratio of the distance from the connecting weld seam between the ferrite-phase steel plate and the austenite-phase steel plate to the non-welded side of the core part of energy absorption of the ferrite-phase steel plate (i.e., the width w0 / 2 of the core part of energy absorption of the ferrite-phase steel plate) to the thickness (t) of the ferrite-phase steel plate is about 3.4.

[0130] The chemical composition and its mass fraction of the steel plate in the austenite phase are 29.4% Mn, 4.3% Si, 1.4% Al, 0.049% C, 0.009% P, 0.008% S, 0.005% N, and the balance is Fe and inevitable impurity elements. The average austenite crystal grain size of the steel plate in the austenite phase is 76 μm. The yield strength of the steel plate in the austenite phase is 304 MPa, and the elongation is 52%. The microstructure of the steel plate in the austenite phase is a single austenite structure. When entering the yield stage, metastable austenite undergoes ε-martensite phase transformation due to the action of strain, and the α'-martensite phase transformation is suppressed. Under the action of repeated tensile and compressive loads, a reversible phase transformation occurs between metastable austenite and strain-induced ε-martensite.

[0131] The chemical composition and its mass fraction of the steel plate in the ferrite phase are 0.30% Mn, 0.05% Si, 0.015% C, 0.05% Ti, 0.012% P, 0.006% S, 0.006% N, and the balance is Fe and inevitable impurity elements. The yield strength of the steel plate in the ferrite phase is 157 MPa, and the elongation is 47%. The microstructure of the steel plate in the ferrite phase is mainly ferrite, and the average ferrite crystal grain size is 50 μm.

[0132] The surrounding restraint component is a restraint casing formed by combining a steel pipe and internally filled concrete. In order to remove the friction between the surrounding restraint component and the energy absorption structure in the core, a non-bonding material layer is provided between the surrounding restraint component and the energy absorption structure in the core.

[0133] When an axial steel damper is subjected to approximately 30 cycles of periodic alternation of tension and compression at a displacement of 42 mm, fatigue failure occurs. The limit allowable displacement of the axial steel damper is approximately 42 mm. The yield displacement is obtained from the repeated stress-strain curve at a displacement of 42 mm and is approximately 4.5 mm. The ratio of the limit allowable displacement to the yield displacement (i.e., ductility) of the axial steel damper is calculated to be approximately 9.3. Therefore, in this comparative example, the ratio of the limit allowable displacement to the yield displacement of the axial steel damper is less than 10.

[0134] The above description of the embodiments is for those skilled in the art to understand and use the present invention. It is obvious that those skilled in the art can easily make various changes to these embodiments without creative efforts and apply the general principles described herein to other embodiments. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art within the scope not departing from the disclosure of the present invention are within the protection scope of the present invention.

Description of Reference Numerals

[0135] 1. Steel plate of ferrite phase 11. Welded side 12. Non-welded side 2. Steel plate of austenite phase 3. Weld joint 4. Surrounding restraint steel pipe 5. Axial steel damper 6. Intermediate connection plate 7. Steel brace 8. Spherical hinge 9. Concrete

Claims

1. An energy absorption structure in a core for an axially steel damper that absorbs external vibration energy when the axially steel damper is periodically and alternately subjected to plastic deformation in tension and compression, The energy absorption structure in the core includes at least one steel plate of austenite phase and one steel plate of ferrite phase. The steel plate of ferrite phase must be adjacent to the steel plate of austenite phase and can be connected only by welding. The welding seam for connection between the steel plate of austenite phase and the ferrite steel plate is parallel to the axial direction of the energy absorption structure in the core, The microstructure of the steel plate of austenite phase is composed of metastable austenite and thermally induced ε martensite with a volume ratio of 10% or less, and the average metastable austenite crystal grain size is 400 μm or less. When subjected to tensile or compressive plastic deformation, the metastable austenite of the steel plate of austenite phase is induced to undergo ε martensite phase transformation by the action of strain, and the α′ martensite phase transformation is suppressed. When periodic and alternating plastic deformations in tension and compression are applied, a reversible phase transformation occurs between austenite and strain-induced ε martensite inside the steel plate of austenite phase, The microstructure of the steel plate of ferrite phase is mainly ferrite, and the average ferrite crystal grain size is 200 μm or less, The yield strength of the steel plate of austenite phase is 220 MPa or more, and the elongation is 40% or more. The yield strength of the steel plate of ferrite phase is less than 180 MPa, and the elongation is 30% or more, The thickness of the steel plate of austenite phase is 0.4 times or more the thickness of the steel plate of ferrite phase, The ratio of the total cross-sectional area of the core part for energy absorption of all the steel plates of ferrite phase to the total cross-sectional area of the core part for energy absorption of all the steel plates of austenite phase is 0.6 or more. The energy absorption structure in the core is characterized by this.

2. When both sides of the steel plate of ferrite phase are not simultaneously adjacent to and connected to the steel plate of austenite phase, the ratio of the distance from the welding seam for connection between the steel plate of ferrite phase and the adjacent steel plate of austenite phase to any non-welded side of the core part for energy absorption of the steel plate of ferrite phase to the thickness of the steel plate of ferrite phase is 25 or less. The energy absorption structure in the core according to Claim 1 is characterized by this.

3. When the geometric shape of the cross-section of the ferrite-phase steel plate or austenite-phase steel plate does not change along the longitudinal direction, the core part of the energy absorption of the ferrite-phase steel plate or austenite-phase steel plate is, that is, the entire length of the ferrite-phase steel plate or austenite-phase steel plate, When the geometric shape of the cross-section of the ferrite-phase steel plate or austenite-phase steel plate has the characteristic that both ends are wide and the center is narrow along the longitudinal direction, the core part of the energy absorption of the ferrite-phase steel plate or austenite-phase steel plate is the narrow part in the center of the ferrite-phase steel plate or austenite-phase steel plate, The energy absorption structure in the core according to claim 1 or 2, characterized in that.

4. The mass fraction of the chemical components of the austenite-phase steel plate is C≤0.15%, 22.0%≤Mn≤34.0%, 3.5%≤Si≤5.5%, Al≤2.5%, Ni≤5.0%, Cu≤2.0%, P≤0.03%, S≤0.03%, N≤0.02%, and the balance is Fe and inevitable impurity elements, and the mass fractions of Al, Ni and Cu satisfy Ni / Cu≥0.25 and Al + 0.4Ni + 0.25Cu≤3.5%, The energy absorption structure in the core according to claim 1, characterized in that.

5. The mass fraction of the chemical components of the ferrite-phase steel plate is C≤0.1%, Mn≤1.0%, Si≤0.8%, Ti≤0.15%, Nb≤0.1%, V≤0.2%, P≤0.03%, S≤0.03%, N≤0.02%, and the balance is Fe and inevitable impurity elements, The energy absorption structure in the core according to claim 1, characterized in that.

6. The cross-section of the energy absorption structure in the core is selected as an axisymmetric geometric shape, The energy absorption structure in the core according to claim 1, characterized in that.

7. An axial steel damper comprising the energy absorption structure in the core according to any one of claims 1 to 6 and a surrounding restraint component, wherein the surrounding restraint component suppresses the lateral displacement of the energy absorption structure in the core and prevents the energy absorption structure in the core from buckling and becoming unstable, Characterized by.

8. The axial steel damper according to claim 7, wherein the surrounding restraint component is selected from a restraint casing formed by a combination of a steel pipe and internally filled concrete, or a reinforced concrete restraint casing, or a pure steel structure restraint member.

9. The ratio of the ultimate allowable displacement to the yield displacement of the axial steel damper is 10 or more, and the ultimate allowable displacement is 1 / 60 or more of the length of the axial steel damper. Under the condition of this ultimate allowable displacement, the axial steel damper can complete at least 30 cycles of alternating plastic deformation of tension and compression, and the reduction in load capacity is less than 15%. The axial steel damper according to claim 7, characterized in that.

10. The axial steel damper according to claim 7, wherein the axial steel damper is used alone or combined with other steel braces to form an axial energy absorption brace and installed in a building or structure, connected to the main column-beam structure of the building or structure to form an entirety, and serves to absorb external vibration energy.

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