WO2023125063A1

WO2023125063A1 - Core energy dissipation structure and axial steel damper

Info

Publication number: WO2023125063A1
Application number: PCT/CN2022/139505
Authority: WO
Inventors: 杨旗; 丁孙玮; 王敏; 杨凯; 涂田刚; 洪彦昆; 徐斌
Original assignee: 上海材料研究所有限公司
Priority date: 2021-12-27
Filing date: 2022-12-16
Publication date: 2023-07-06
Also published as: CN114351884A; CN114351884B

Abstract

The present invention relates to a core energy dissipation structure and an axial steel damper. The axial steel damper comprises a core energy dissipation structure and a peripheral restraint member. The core energy dissipation structure at least comprises an austenite structure steel plate and a ferrite structure steel plate; the ferrite structural steel plate is necessarily and only adjacent to the austenite structure steel plate, and is connected to the austenite structure steel plate by means of welding. The microstructure of the austenite structure steel plate is primarily metastable austenite, and when the austenite structure steel plate is subjected to periodic alternating stretching-compression plastic deformation, a reversible phase change between austenite and strain-induced ε martensite occurs in the austenite structure steel plate. The ratio of the maximum allowable displacement to the yield displacement of the axial steel damper of the present invention is not less than 10, and the maximum allowable displacement is not less than 1/60 of the length of the axial steel damper. The axial steel damper is able to complete at least 30 cycles of periodic alternating stretching-compression plastic deformation under the maximum allowable displacement.

Description

A core energy dissipation structure and an axial steel damper

technical field

The invention belongs to the technical field of building engineering structures, and relates to a core energy dissipation structure and an axial steel damper.

Background technique

Both high-intensity earthquakes and external long-lasting vibrations will cause great harm to high-rise buildings and structures. The use of energy-dissipating and shock-absorbing devices and technologies can effectively absorb external shock energy and minimize damage to buildings and structures. Buckling-resistant energy-dissipating brace is a common axial energy-dissipating shock-absorbing element, which is widely used in civil engineering structures because of its direct force transmission path and good economy. Under small earthquakes, the anti-buckling energy-dissipating brace can provide additional stiffness to the beam-column structure and reduce structural deformation; under larger vibrations, the anti-buckling energy-dissipating brace can yield under both tension and compression, showing good performance. hysteresis energy consumption capacity.

At present, anti-buckling energy-dissipating braces mainly use steel such as LY225 low-yield point steel and Q235 structural steel as energy-dissipating core materials (the above-mentioned steel types are all low-carbon ferritic steels). The anti-buckling energy-dissipating bracing made of the above-mentioned steel types can only provide a certain degree of stiffness and cannot start a substantial Yield deformation to dissipate seismic energy. More critically, due to the low ductility and low cycle fatigue deformation capacity of steel types, the cumulative plastic deformation and cumulative plastic energy dissipation effect of the above steel types caused by cyclic deformation are limited. Therefore, under rare earthquakes ('big earthquakes'), buckling-resistant energy-dissipating braces made of the above-mentioned steel types will undergo fatigue fracture after fewer cycles of tension-compression cyclic loading; and, in rare earthquakes Or under extremely rare earthquakes, the anti-buckling energy-dissipating brace cannot achieve the same redundancy failure as the main structure of the building (that is, the anti-buckling energy-dissipating brace fails earlier than the failure of the main structure of the building, so that the main structure of the building cannot obtain buckling-proof Further protective effect of energy-dissipating support). In summary, the anti-buckling energy-dissipating brace made of low-carbon ferritic steel cannot play the role of shock absorption and protection under earthquakes of different intensities.

Fe-Mn-Si austenitic alloys with low stacking fault energy within a certain composition range have excellent low-cycle fatigue properties and weldability, and are potentially used as elastic-plastic damping steels to make anti-buckling energy-dissipating supports; correspondingly, this type of anti-buckling Buckling energy-dissipating braces can have excellent accumulative plastic deformation capacity (that is, the core plate can withstand large cumulative tensile and compressive displacements before the anti-buckling energy-dissipating braces fail due to fatigue). The fundamental reason for the excellent low-cycle fatigue properties of Fe-Mn-Si alloys with low stacking fault energy is that dislocation plane slip and reversible ε-martensitic transformation occur in the material during cyclic deformation. However, compared with LY225 low yield point steel and Q235 structural steel, the above-mentioned Fe-Mn-Si alloy has high yield strength, which makes the yield force and yield displacement of anti-buckling energy-dissipating support larger, and the ductility may still be low (Here, "ductility" is described by the ratio of the ultimate allowable displacement to the yield displacement of buckling-resistant dissipative braces or axial dissipative elements). Correspondingly, it is difficult for energy-dissipating braces to play the role of energy dissipation and shock absorption under small and moderate earthquakes, and under large earthquakes, the energy-dissipating braces will add a large force to the main structure of the building through the connection nodes. Therefore, the anti-buckling energy-dissipating bracing made of low-stacking fault energy Fe-Mn-Si alloy steel has limited protection for the main structure of the building. In addition, the work hardening degree of Fe-Mn-Si alloy is relatively high in a single cycle of deformation, which will also weaken the energy dissipation effect of the anti-buckling energy dissipation support. The above reasons limit the low stacking fault energy Fe-Mn-Si alloys to be widely used as energy dissipation and shock absorption materials in practical engineering.

Contents of the invention

Based on the above-mentioned technical status, it is urgent to develop an axial steel damper with small yield displacement, excellent ductility and cumulative plastic deformation capacity, and the same redundancy failure rate as the main structure of the building. Accordingly, the present invention provides a core dissipative structure and an axial steel damper. The axial steel damper provided by the invention can exert the energy dissipation and shock absorption effect and protect the building against earthquakes under different intensities of earthquakes, and can replace the existing anti-buckling energy-dissipating support to achieve a significant improvement in the anti-seismic protection performance of the building.

Compared with the existing anti-buckling energy-dissipating supports, the axial steel damper and the core energy-dissipating structure of the present invention have excellent ductility and cumulative plastic deformation capacity, and can achieve the same redundancy failure as the main structure of the building; compared with the potential The anti-buckling energy-dissipating support made of low-stacking-fault energy Fe-Mn-Si austenitic alloy steel, the axial steel damper and core energy-dissipating structure of the present invention have the characteristics of small yield displacement, excellent ductility and low cost.

The purpose of the present invention can be achieved through the following technical solutions:

The present invention firstly provides a core energy-dissipating structure, which is used for the axial steel damper, and plays the role of absorbing the external vibration energy when the axial steel damper is subjected to periodic alternating tension-compression plastic deformation,

The core energy-dissipating structure includes at least one steel plate with austenitic structure and one steel plate with ferritic structure, and the steel plate with ferritic structure must and can only be adjacent to the steel plate with austenitic structure and connected by welding , and the connecting weld between the austenitic structure steel plate and the ferrite structure steel plate is parallel to the axial direction of the steel damper and the energy dissipation structure of the core;

The microstructure of the austenitic structure steel plate is composed of metastable austenite and thermally induced ε martensite with a volume fraction of no more than 10%, and the average grain size of the metastable austenite is no more than 400 μm. During tensile or compressive plastic deformation, the metastable austenite of the austenitic steel plate induces the ε martensitic transformation under the action of strain and the α′ martensitic transformation is suppressed; - During compression plastic deformation, a reversible phase transformation between austenite and strain-induced ε martensite occurs inside the steel plate with austenitic structure;

The microstructure of the ferritic steel plate is mainly ferrite, and the average grain size of ferrite is not more than 200 μm;

The yield strength of the austenitic steel plate is not less than 220MPa, and the elongation at break is not less than 40%, and the yield strength of the steel plate with ferrite structure is less than 180MPa, and the elongation at break is not less than 30%;

The thickness of the austenitic steel plate is more than 0.4 times the thickness of the ferritic steel plate;

In the energy-dissipating structure of the core, the ratio of the sum of the cross-sectional areas of the core energy-dissipating sections of all ferritic steel plates to the sum of the cross-sectional areas of the core energy-dissipating sections of all austenitic steel plates is not less than 0.6.

In the energy-dissipating structure of the core, when the steel plates with ferrite structure are connected adjacent to the steel plates with austenite structure on both sides at the same time, the distance between the steel plates with ferrite structure and adjacent austenite structure steel plates The ratio of the distance between the connecting weld to any non-welding side of the core energy dissipation section of the ferritic steel plate to the thickness of the ferritic steel plate is not greater than 25.

The present invention stipulates that: in the core energy dissipation structure, if the cross-sectional geometry of the steel plate with ferrite structure or steel plate with austenite structure remains unchanged along the length direction, then the steel plate with ferrite structure or steel plate with austenite structure The core energy-consuming section of the steel plate is the full length of the steel plate with ferrite structure or austenite structure. At this time, the cross-section of the core energy-consuming section of the steel plate with ferrite structure or austenite structure is is the cross-section of the ferritic steel plate or austenitic steel plate; if the cross-sectional geometric shape of the ferritic steel plate or austenitic steel plate presents the characteristics of wide ends and narrow middle along the length direction, then The core energy-consuming section of the steel plate with ferrite structure or steel plate with austenite structure is the narrow part in the middle of the steel plate with ferrite structure or steel plate with austenite structure. At this time, the steel plate with ferrite structure or austenite structure The cross-section of the core energy-dissipating section of the steel plate with the ferrite structure is the cross-section of the narrow part in the middle of the steel plate with the ferrite structure or the steel plate with the austenite structure.

The present invention defines that the core energy dissipation structure includes at least one steel plate with austenite structure and one steel plate with ferrite structure. The microstructure of the austenitic steel plate is metastable austenite and thermally induced ε martensite with a volume fraction of no more than 10%. Flaky ε martensite with single-variant crystallographic features avoids strong interaction between heat-induced ε martensite and strain-induced ε martensite in the original matrix structure, thus promoting austenite and strain-induced ε The reversible phase transformation between martensites reduces the occurrence of crystal defects in the matrix of austenitic steel plates and delays the expansion of fatigue cracks, so that austenitic steel plates exhibit excellent low-cycle fatigue properties and cumulative plastic deformation capabilities, which in turn contributes to strengthening The low-cycle fatigue performance and cumulative plastic deformation capacity of the core energy-dissipating structure as a whole (when the core energy-dissipating structure is used in the axial steel damper, that is, the axial steel damper).

In addition, the present invention defines that the metastable austenite inside the austenitic steel plate is restrained from the α' martensitic transformation during tensile or compressive plastic deformation. This is because, when the metastable austenite undergoes excessive α′ martensitic transformation under the action of plastic strain, deformation localization will easily occur inside the steel plate, resulting in a sharp decline in the low cycle fatigue performance of the austenitic steel plate . The present invention limits the average grain size of the metastable austenite to not exceed 400 μm. This is because when the austenite grains are too coarse, the reversible transformation between austenite and strain-induced ε martensite will be significantly inhibited, thereby significantly reducing the fatigue resistance of the austenitic steel plate. The present invention strictly limits the microstructure of the austenitic structure steel plate, and its purpose is to ensure that the austenitic structure steel plate can withstand large strain fatigue deformation, and ensure that the axial steel damper can function under medium and high-intensity earthquakes. Fatigue failure occurs early.

The ferritic structure steel plate has low yield strength, high elastic modulus and low work hardening degree in cyclic deformation cycles, thus helping to reduce the yield force and yield of the energy-dissipating structure of the core (that is, the axial steel damper) Displacement and work hardening within cyclic deformation cycles enable the steel damper to achieve yield energy dissipation under small and medium-intensity earthquakes. The present invention limits the average grain size of ferrite to not more than 200 µm. This is because when the ferrite grains are too coarse, fatigue cracks will easily initiate and propagate from the grain boundaries, thereby significantly reducing the fatigue resistance of the ferrite structure steel plate. Therefore, the restriction on ferrite grain size (and elongation) is aimed at ensuring proper fatigue resistance of ferritic steel plates.

In the energy-dissipating structure of the core, the ferritic steel plate must be closely connected with the austenitic steel plate by welding, otherwise the special contribution of the above-mentioned austenitic steel plate and ferritic steel plate to the overall core energy-dissipating structure will be absent or difficult to fully manifest. This is because, when the austenitic steel plate and the ferritic steel plate are closely connected, the austenitic steel plate will restrain the deformation of the ferritic steel plate, and this constrained internal stress will increase the ferritic steel plate. Anti-fatigue performance (that is, "special contribution"); when fatigue failure occurs in the energy-dissipating member of the core, the two types of steel plates often break in the same section. When the steel plates of the same type are connected, this constraint mechanism does not exist; correspondingly, when a ferritic steel plate is adjacent to another ferritic steel plate and welded together, the fatigue resistance of the two ferritic steel plates is not good. will be promoted. When the two types of steel plates are not connected, firstly, the restraining mechanism of the austenitic steel plate on the deformation of the ferritic steel plate does not exist, and the overall fatigue resistance of the core energy-dissipating structure cannot be improved; in addition, due to the austenitic steel plate The anti-fatigue performance of the ferritic steel damper is obviously better than that of the ferritic structure steel plate, so in the process of alternating tension-compression plastic deformation, the ferrite structure steel plate will break first, and the bearing capacity of the axial steel damper will decrease. Therefore, the present invention restricts that the steel plate with ferrite structure in the energy dissipation structure of the core must be closely connected with the steel plate with austenite structure by means of welding.

The invention limits that the yield strength of the austenitic steel plate constituting the core energy dissipation structure is not less than 220MPa, and the elongation at break is not less than 40%; the yield strength of the steel plate with ferrite structure is less than 180MPa, and the elongation at break is not less than 30%. 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 capacity and fatigue properties, so that the axial steel damper has the following characteristics of ductility and cumulative deformation capacity: limit allowable displacement and yield The displacement ratio is not less than 10, and the limit allowable displacement is not less than 1/60 of the length of the core energy-dissipating structure (or axial steel damper), and under this limit allowable displacement condition, the axial steel damper can complete At least 30 cycles of alternating tension and compression plastic deformation and the bearing capacity attenuation is less than 15%.

The present invention limits the thickness of the steel plate with austenite structure to be more than 0.4 times the thickness of the steel plate with ferrite structure. This is because, when the thickness of the austenitic steel plate is less than 0.4 times the thickness of the ferritic steel plate, it is difficult for the austenitic steel plate to pass through the connection weld to the ferrite structure during the tension-compression alternating plastic deformation process. The deformation of the steel plate forms sufficient constraints.

In the present invention, if the ratio of the sum of the cross-sectional areas of the core energy-consuming sections of all ferritic steel plates to the sum of the cross-sectional areas of the core energy-consuming sections of all austenitic steel plates is too small (less than 0.6), the core The deformation and load bearing of the energy dissipation structure are mainly dominated by the austenitic steel plate, which will significantly increase the yield force and yield displacement of the core energy dissipation structure, which will lead to a significant decrease in the ductility of the core energy dissipation structure and the axial steel damper (Steel dampers have a ductility lower than 10). Therefore, the present invention limits the ratio of the sum of the cross-sectional areas of the core energy-consuming sections of all ferritic steel plates to the sum of the cross-sectional areas of the core energy-consuming sections of all austenitic steel plates not less than 0.6; further, from reducing the core Considering the yield displacement of the internal energy-dissipating structure, it is preferable that the ratio of the sum of the cross-sectional areas of the core energy-dissipating sections of all ferritic steel plates to the sum of the cross-sectional areas of the core energy-dissipating sections of all austenitic steel plates is not less than 0.8.

In one embodiment of the present invention, when the steel plate with ferrite structure is not connected adjacent to the steel plate with austenite structure on both sides at the same time, the steel plate with ferrite structure and the steel plate with adjacent austenite structure The ratio of the distance between the connecting weld seam to any non-welded side of the core energy dissipation section of the ferrite steel plate to the thickness of the ferrite steel plate is not greater than 25. Here, the following two connection methods between the ferritic steel plate and the adjacent austenitic steel plate need to be considered:

In the first type, the steel plate with ferrite structure is connected adjacent to the steel plate with austenite structure on only one side, that is, the connecting weld of the two types of steel plates is located on one side of the steel plate with ferrite structure. At this time, the steel plate with ferrite structure Plates have only one non-welded side. Common connection forms include: 2 steel plates with ferritic structure and 1 steel plate with austenitic structure are connected to form a cross structure, in which 2 steel plates with ferritic structure are vertically located above and below the steel plate with austenitic structure; The ferritic steel plate and one austenitic steel plate are connected to form a T-shaped structure, in which the ferritic steel plate is placed perpendicular to the austenitic steel plate, and the connecting weld of the two types of steel plates is located on the austenitic steel plate ( That is, the connection weld is located between the two sides of the austenitic steel plate).

In the second type, the connecting weld of the two types of steel plates is located on the ferrite steel plate, that is, the connecting weld is located between the two sides of the ferritic steel plate (the connecting weld is not on any side of the ferritic steel plate). One side), at this time, the ferritic steel plate has two non-welded sides. Common connection forms include: 2 ferritic steel plates and 1 austenitic steel plate are connected to form an I-shaped structure, in which the austenitic steel plate is vertically located between the 2 ferritic steel plates; A steel plate with austenitic structure and an austenitic steel plate are connected to form a T-shaped structure, in which the steel plate with ferritic structure is placed perpendicular to the steel plate with austenitic structure, and the connecting weld of the two types of steel plates is located on the steel plate with The connecting weld is located between the two sides of the ferritic steel plate).

For the above two cases, when the ratio of the distance between the constrained connection weld to any non-welding side of the core energy-consuming section of the ferrite steel plate and the thickness of the ferrite steel plate is too large (greater than 25), The confinement effect of the part of the material far away from the weld in the ferritic steel plate will be almost lost. Compared with the material near the weld constraint, this part of the material is prone to fatigue damage, which will lead to the loss of the entire ferritic steel plate and the core. failure of the structure. Therefore, the present invention defines that the ratio of the distance between the constrained connection weld to any non-welding side of the core energy dissipation section of the ferrite steel plate and the thickness of the ferrite steel plate is not greater than 25.

When the ferritic steel plate is connected to the adjacent austenitic steel plate on both sides, the ferritic steel plate is constrained and protected on both sides, so fatigue cracks cannot form from both sides, which will Significantly improve the fatigue resistance of ferritic structure steel plate. In the present invention, when both sides of the ferritic steel plate are connected to the austenitic steel plate, in principle the distance between the welds on both sides of the ferritic steel plate is not restricted, but still needs The condition that "the ratio of the sum of the cross-sectional areas of the core energy-dissipating sections of all ferritic steel plates to the sum of the cross-sectional areas of the core energy-dissipating sections of all austenitic steel plates" is met is not less than 0.6. Moreover, from the perspective of the stability of the energy-dissipating structure of the core, it is suggested that the distance between the welds on both sides of the ferritic steel plate should not exceed 80 times the thickness of the ferritic steel plate. The case where the ferritic steel plate is connected to the austenitic steel plate on both sides includes: one ferritic steel plate and two austenitic steel plates are connected to form an I-shaped structure, in which the ferritic steel plate is vertical Located between two austenitic steel plates.

The invention defines the limit allowable displacement and yield displacement of the axial steel damper. The limit allowable displacement is the maximum displacement allowed by the axial steel damper during periodic alternating tension-compression plastic deformation, and at this maximum displacement, the axial steel damper can withstand at least 30 cycles of tension- Compressive plastic deformation. When the cyclic deformation displacement exceeds the maximum allowable displacement, the axial steel damper cannot complete 30 cycles of cyclic deformation and fails. The yield displacement is the displacement corresponding to the yield deformation of the axial steel damper when the limit allowable displacement is subjected to periodic alternating tension-compression deformation. Fig. 1 illustrates the hysteretic curve formed when the axial steel damper undergoes periodic alternating tension-compression plastic deformation at the limit allowable displacement. The elastic stiffness of the axial steel damper is obtained from the unloading section of the hysteretic curve. When the center of the hysteresis curve is not at the origin of the coordinate axis, the maximum displacement of the stretched part of the hysteresis curve is

The maximum displacement of the compression part of the hysteresis curve is

Then the limit allowable displacement u _d,max is calculated as

If the center of the hysteresis curve is at the origin of the coordinate axis, the maximum displacement of the stretched part of the hysteresis curve is the same as the maximum displacement of the compressed part. At this time,

The elastic stiffness corresponding to the unloading section of the tensile part of the hysteretic curve is

The elastic stiffness corresponding to the unloading section of the compression part of the hysteresis curve is

if

Then the elastic stiffness K _d of the axial steel damper is calculated as

if

At this time there is the elastic stiffness of the axial steel damper

A straight line whose slope is the elastic stiffness K _d is drawn through the coordinate origin, and the intersection point of the straight line with the stretched part of the hysteresis curve is the yield displacement during cyclic deformation stretching

The intersection of the straight line and the compression part of the hysteresis curve is the yield displacement during cyclic deformation compression

The yield displacement u _dy of the axial steel damper is calculated as

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 can be obtained, that is, the ductility of the steel damper.

In one embodiment of the present invention, the mass percentages of the chemical composition of the austenitic steel plate are defined as: 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 rest are Fe and unavoidable impurity elements. Among them, the mass percentages of Al, Ni and Cu also meet the following requirements Relationship: Ni/Cu≥0.25 and Al+0.4Ni+0.25Cu≤3.5%.

Materials meeting the above compositional requirements have a microstructure of metastable austenite and thermally induced ε martensite with a volume fraction of not more than 10%, and the metastable austenite is under alternating tension-compression loads Reversible ε martensite transformation occurs (that is, metastable austenite and strain-induced ε martensite undergo mutual transformation under alternating loads) and α′ martensite transformation is inhibited, so that the steel plate material Has excellent low cycle fatigue properties.

Under the premise of not changing the above basic microstructure characteristics, the chemical composition of the austenitic steel plate may also contain a small amount of Cr element; the mass percentage of Cr element is limited in the present invention: Cr≤2%.

When it has the above alloy composition and the average grain size of the metastable austenite is not more than 400 μm, the yield strength of the austenitic steel plate is not less than 220 MPa, and the fracture elongation is not less than 40%.

In one embodiment of the present invention, the mass percentages of the chemical composition of the steel plate with a defined ferrite structure are: 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 rest are Fe and unavoidable impurity elements.

Materials meeting the above compositional requirements have a microstructure that is predominantly ferrite. Under the premise of not changing the above-mentioned basic microstructure characteristics, the chemical composition of the ferritic steel plate can also contain a small amount of Cu, Cr and Ni elements; the mass percentage of Cu, Cr and Ni elements limited by the present invention is: Cu≤0.5 %, Cr≤1%, Ni≤1%.

When it has the above alloy composition and the average grain size of ferrite is not more than 200 μm, the yield strength of the steel plate with ferrite structure is less than 180 MPa, and the elongation at break is not less than 30%.

In one embodiment of the present invention, the cross-section of the core energy dissipation structure may have any type of axisymmetric geometry. The cross-sectional forms with any type of axisymmetric geometry mainly include cross-shaped, I-shaped and so on.

In one embodiment of the present invention, the energy dissipation structure of the core of the axial steel damper may adopt a cross-section form that is narrow in the middle and wide at both ends. As shown in Figure 2 and Figure 3. Fig. 2 shows the geometry and relative positions of ferrite steel plates and austenite steel plates forming a core energy-dissipating structure, and Fig. 3 is a schematic diagram of the corresponding core energy-dissipating structure formed by welding and assembling.

In the present invention, when the two types of steel plates have geometric shapes that are wide at both ends and narrow in the middle (the narrow part in the middle of the steel plate is called the core energy-dissipating section), the narrow part in the middle of the core energy-dissipating structure composed of the two types of steel plates is called The core energy dissipation section of the core energy dissipation structure. Since the axial steel damper is connected with the beam-column main structure of the building or other steel supports through connecting nodes or other connecting members, the above-mentioned cross-sectional geometric design of the energy dissipation structure of the core is to make the plasticity of the steel damper The deformation is only concentrated in the core energy-dissipating section of the core energy-dissipating structure, avoiding obvious yield deformation or even failure of the connecting nodes or other connecting components during the service of the axial steel damper.

The reasonable selection of the ratio of the cross-sectional area of the core energy-dissipating section to the two ends of the core energy-dissipating structure mainly depends on the material strength of the core energy-dissipating structure and connecting nodes or other connecting members, as well as the connection strength between the two. In principle, the yield force of the connecting nodes or other connecting components needs to be greater than the yield force of the core energy-dissipating structure when yielding.

The present invention also provides an axial steel damper, including the core energy-dissipating structure and peripheral constraining members, the core energy-dissipating structure plays a role in the axial steel damper subjected to periodic alternating tension-compression plastic deformation The function of absorbing external shock energy while the peripheral restraining member plays a role in restraining the lateral displacement of the energy-dissipating structure of the core and preventing buckling and instability of the energy-dissipating structure of the core.

In one embodiment of the present invention, the outer constraining member of the axial steel damper is selected as a constraining sleeve formed by a combination of steel pipe and inner concrete, or a reinforced concrete constraining sleeve, or a pure steel structural constraint.

The present invention also provides the application of the axial steel damper. The axial steel damper is used alone or combined with other steel supports to form an axial energy-dissipating support, installed in buildings or structures, and The beam-column main structure and connection nodes are connected to form a whole, which plays the role of dissipating external vibration energy.

In one embodiment of the present invention, the axial steel damper can be connected with other steel supports through a flange or an intermediate connecting plate to form an axial energy-dissipating support to meet the needs of prefabricated buildings and rapid replacement after earthquakes. requirements. The combined axial energy-dissipating support is installed in buildings and structures, and is connected with the beam-column main structure and connection nodes of the building or structure to form a whole, which plays the role of energy-dissipating external vibration and can significantly improve the earthquake resistance of buildings and structures performance.

In one embodiment of the present invention, the axial steel damper is directly installed in buildings and structures, and is connected with the beam-column main structure and connection nodes of buildings or structures to form a whole, which acts as an external energy-dissipating damper. The effect of vibration can significantly improve the seismic performance of buildings and structures.

The structural size of the axial steel damper of the present invention is generally smaller than that of conventional anti-buckling energy-dissipating supports, and its own weight is lighter. Fig. 4 is a schematic diagram of an axial energy-dissipating support formed by a replaceable axial steel damper combined with other steel supports, and its three-dimensional perspective view is shown in Fig. 5 . One end of the axial steel damper is connected to the gusset plate of the building through an intermediate connecting plate and a spherical hinge, and the other end of the axial steel damper is combined with other steel supports through an intermediate connecting plate (or flange) to form a shaft support for energy consumption.

The research of this application found that the root cause of the low low-cycle fatigue performance of low-carbon ferritic steel is that during the cyclic deformation process, due to the frequent occurrence of cross-slip and the irreversibility of plastic deformation on the microscopic level, the material exhibits reduced structural stability and plasticity. Strain localization; as the cyclic cumulative strain increases, fatigue cracks will nucleate from strain-incompatible places (such as grain boundaries, ferrite/cementite phase boundaries) or resident slip zones on the surface of the material, and then along the grain Boundary or intragranular growth until the material undergoes intergranular or transgranular fatigue failure. Therefore, the ductility and cumulative plastic deformation capacity of steel dampers made of low-carbon ferritic steels (such as LY225 and Q235) are low. The anti-buckling energy-dissipating bracing made of low-stacking fault energy Fe-Mn-Si alloy steel also has limited protection for the main structure of the building. The invention develops an axial steel damper which has small yield displacement, excellent ductility and cumulative plastic deformation capacity, and can fail at the same redundancy as the main structure of the building.

Compared with the prior art, the beneficial effects of the present invention are as follows:

1) Compared with the existing anti-buckling energy-dissipating supports (the core energy-dissipating structure is usually made of LY225 or Q235 steel plate), the core energy-dissipating structure of the axial steel damper of the present invention has good ductility and cumulative plastic deformation capacity, The ratio of the limit allowable displacement to the yield displacement is not less than 10, and the limit allowable displacement is not less than 1/60 of the axial length of the steel damper; and, under the limit allowable displacement condition, the axial steel damper can complete at least 30 cycles of alternating tension-compression plastic deformation and bearing capacity attenuation is less than 15%. The existing anti-buckling energy-dissipating braces cannot achieve the above-mentioned index performance.

2) Compared with the anti-buckling energy-dissipating support made of potential low-stacking fault energy Fe-Mn-Si austenitic alloy steel, the core energy-dissipating structure of the axial steel damper of the present invention has small yield displacement and yield force , low degree of work hardening, good ductility and low cost. The applicant found that the buckling energy-dissipating brace made of low-stacking fault energy Fe-Mn-Si austenitic alloy steel, due to the large yield force and yield displacement, the ratio of the ultimate allowable displacement to the yield displacement is often less than 7, Therefore, the energy consumption effect of this support is not obvious. In addition, the cost of low-stacking-fault-energy Fe-Mn-Si-based austenitic alloy steel is relatively high, and the cost of anti-buckling energy-dissipating supports made entirely of this type of material will be relatively high.

3) Compared with the existing anti-buckling energy-dissipating brace and the anti-buckling energy-dissipating brace made of potential low-stacking fault energy Fe-Mn-Si austenitic alloy steel, the axial steel damper of the present invention has greatly improved ductility , can achieve yield energy dissipation under different intensities of earthquakes, can achieve the same redundancy failure as the main structure of the building, and has excellent cumulative plastic deformation capacity.

4) The axial steel damper of the present invention can be combined with other steel supports to form an axial energy-dissipating support, which meets the requirements of prefabricated buildings and quick replacement after earthquakes. The structural size and self-weight of the axial steel damper of the present invention can be smaller than the structural size and self-weight of conventional anti-buckling energy-dissipating supports.

5) The existing anti-buckling energy-dissipating supports need to be designed and manufactured according to the oblique dimensions of the main structural frame, and the size of the energy-dissipating supports is generally large, which is not conducive to on-site installation and post-earthquake replacement. And the structural size of the axial steel damper of the present invention can usually be smaller than the structural size of the conventional buckling-resistant energy-dissipating support, and its own weight is light, and it is easy to install on site and replace after an earthquake.

In the present invention, in the axial steel damper, the steel plate with austenitic structure constituting the energy-dissipating structure of the core undergoes a reversible phase transformation between austenite and strain-induced ε martensite during the process of alternating tension-compression plastic deformation , so the austenitic steel plate has excellent fatigue deformation performance, so that the axial steel damper can have a very high limit allowable displacement. If the austenitic steel plate used in the energy-dissipating structure of the core of the axial steel damper only undergoes a deformation mechanism of dislocation plane slip under cyclic loading, the corresponding mass percentage of the chemical composition of the austenitic steel plate can be expressed as 0.4%≤C≤0.7%, 16.0%≤Mn≤26.0%, Si≤2.0%, P≤0.02%, S≤0.03%, N≤0.03%, the rest is Fe and unavoidable impurity elements, then the axial Although the ductility and cumulative plastic deformation capacity of the steel damper can be better than that of the existing anti-buckling energy-dissipating brace, it will be significantly lower than the axial steel damper of the present invention.

Description of drawings

Fig. 1 illustrates the hysteretic curve formed when the axial steel damper undergoes periodic alternating tension-compression plastic deformation at the limit allowable displacement. From the limit allowable displacement and yield displacement, the ductility of the axial steel damper is obtained.

Fig. 2 shows the geometrical shapes and relative positions of the steel plates with ferrite structure and austenite structure forming a core energy dissipation structure.

Fig. 3 is a schematic diagram of a core energy dissipation structure of an axial steel damper.

Fig. 4 is a schematic diagram of an axial energy-dissipating support formed by combining an axial steel damper and other steel supports.

Fig. 5 is a three-dimensional perspective view of an axial energy-dissipating support formed by combining an axial steel damper and other steel supports.

Fig. 6 is the geometric shape of the austenitic steel plate constituting the core energy dissipation structure of the axial steel damper in embodiment 1.

Fig. 7 is the geometric shape of the ferrite structure steel plate constituting the energy dissipation structure of the axial steel damper core in embodiment 1.

Fig. 8 is a front view of the core energy dissipation structure of the axial steel damper in Embodiment 1.

Fig. 9 is a top view of the core energy dissipation structure of the axial steel damper in Embodiment 1.

Fig. 10 is a side view of the core energy dissipation structure of the axial steel damper in Embodiment 1.

Fig. 11 is a front view of the axial steel damper in Embodiment 1.

Fig. 12 is a top view of the axial steel damper in Embodiment 1.

Fig. 13 is an A-A sectional view of the axial steel damper in Embodiment 1.

Fig. 14 is the hysteresis curve when the axial steel damper in embodiment 1 undergoes periodic alternating tension-compression plastic deformation.

Fig. 15 is the hysteresis curve of the axial steel damper in embodiment 2 when undergoing periodic alternating tension-compression plastic deformation.

Labels in the figure: 1. Steel plate with ferrite structure; 11. Welded side; 12. Non-welded side; 2. Steel plate with austenitic structure; 3. Weld seam; 4. Peripheral restraint steel pipe; 5. Axial steel damper; 6. Intermediate connecting plate; 7. Steel support; 8. Ball hinge; 9. Concrete.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

Example 1:

An axial steel damper consisting of a core dissipative structure and peripheral constraining members.

The cross-section of the core energy-dissipating structure has a cross-shaped axisymmetric geometry, and its symmetry axis is the axial direction of the steel damper. The cross-section is narrow in the middle and wide at both ends along the axial direction. As shown in Figure 2 and Figure 3, the core energy dissipation structure is composed of one austenitic steel plate 2 and two ferritic steel plates 1, the austenitic steel plate 2 and the ferritic steel plate 1 are along the longitudinal length The same; two ferritic steel plates 1 are respectively placed above and below the austenitic steel plate 2, with the longitudinal centerline of the austenitic steel plate 2 as the axis of symmetry; the two ferritic steel plates 1 are respectively connected to the austenitic The ferritic steel plate 2 is closely connected by welding, and the weld 3 is parallel to the axial direction of the energy dissipation structure of the core and the steel damper. In Fig. 2, the two sides of the ferritic steel plate 1 are the welding side 11 and the Non-welding side 12.

The geometric shape of the austenitic steel plate forming the energy dissipation structure of the core is shown in Figure 6. The total length of the steel plate with austenitic structure L=2000mm; the length L ₀ =1530mm and the width W ₀ =160mm of the central part of the steel plate (core energy-dissipating section); the thickness T of the steel plate=16mm.

The chemical composition and mass percentage of the steel plate with austenitic structure are: 29.4% Mn, 4.3% Si, 1.4% Al, 0.049% C, 0.009% P, 0.008% S, 0.005% N, the rest is Fe and unavoidable impurity elements. The yield strength of the austenitic steel plate is 304 MPa, and the elongation at break is 52%. The microstructure of the austenitic steel plate is a single austenite structure, and the average austenite grain size is 76 μm; when entering the yield stage, the metastable austenite undergoes ε martensitic transformation under the action of strain and The α′ martensite transformation is suppressed and a reversible transformation between metastable austenite and strain-induced ε martensite occurs under tension-compression alternating loads.

The geometric shape of the ferrite structure steel plate forming the energy dissipation structure of the core is shown in Figure 7. The total length of the steel plate with ferrite structure l=2000mm; the length l 0 of the central part of the steel plate (core energy dissipation section) l ₀ =1530mm, the width w ₀ /2=80mm; the thickness of the steel plate t=16mm.

The chemical composition and mass percentage of the steel plate with ferrite structure are: 0.30% Mn, 0.05% Si, 0.015% C, 0.05% Ti, 0.012% P, 0.006% S, 0.006% N, the rest is Fe and unavoidable impurity elements. The yield strength of the steel plate with ferrite structure is 157 MPa, and the elongation at break is 47%. The microstructure of the steel plate with ferrite structure is mainly ferrite structure, and the average ferrite grain size is 50 μm.

The thickness of the steel plate with the austenitic structure is the same as the thickness of the steel plate with the ferrite structure. The ratio of the sum of the cross-sectional areas of the core energy-dissipating sections of two ferritic steel plates to the cross-sectional area of the core energy-dissipating section of one austenitic steel plate is 1.0 (greater than 0.6). After welding and assembling, the distance from the connecting weld between the ferritic steel plate and the austenitic steel plate to the non-welding side of the core energy-consuming section of the two ferritic steel plates (that is, the ferrite The ratio of the width w ₀ /2) of the core energy-dissipating section of the microstructure steel plate to the thickness (t) of the ferrite microstructure steel plate is 5.0.

After welding and assembling, the front view, top view and side view of the core energy dissipation structure are shown in Fig. 8, Fig. 9 and Fig. 10 respectively.

The peripheral constraining member is a constraining casing formed by combining the peripheral constraining steel pipe 4 and the inner concrete 9, and the peripheral constraining member plays a role in constraining the lateral displacement of the core energy-dissipating structure and preventing the core energy-dissipating structure from buckling . There is a layer of non-adhesive material between the peripheral constraining member and the core energy-dissipating structure to eliminate friction between the peripheral constraining member and the core energy-dissipating structure.

After assembly, the front view, top view and cross-sectional view along A-A plane of the axial steel damper are shown in Fig. 11, Fig. 12 and Fig. 13 respectively.

Fig. 14 shows the hysteresis curves of the axial steel damper during tension-compression alternate deformation. After 33 cycles of alternating tension-compression with a displacement of 40mm, the axial steel damper still has no fatigue damage and the maximum bearing capacity remains almost unchanged. The working displacement of 40mm is equivalent to 1/50 of the axial length of the steel damper. It can be seen from Fig. 14 that the limit allowable displacement of the axial steel damper is greater than 40 mm. The elastic stiffness is obtained from the unloading section of the 40mm displacement hysteresis curve, and then the yield displacement is about 3.1mm. Then continue to cyclically deform with a displacement of 43mm for 2 weeks. It can be seen from the deformation hysteresis curve that the deformation displacement increases with the tension-compression cycle, and the yield displacement does not change much. Calculate the ratio of the ultimate allowable displacement to the yield displacement (ie ductility) of the axial steel damper to be greater than 12.9.

Therefore, the ratio of the limit allowable displacement to the yield displacement of the axial steel damper described in this embodiment is greater than 10, and the limit allowable displacement is greater than 1/60 of the axial length of the steel damper; and, under the limit allowable displacement condition, The axial steel damper can complete at least 30 cycles of periodic alternating tension-compression plastic deformation and the bearing capacity attenuation is less than 15%. In this embodiment, the axial steel damper can achieve the same redundancy failure as the main structure of the building.

Fig. 4 and Fig. 5 are schematic diagrams of the axial energy-dissipating support formed by combining the axial steel damper and other steel supports in this embodiment. One end of the axial steel damper 5 is connected to the building gusset plate through the intermediate connecting plate 6 and the ball joint 8, and the other end of the axial steel damper 5 is formed by connecting and combining the intermediate connecting plate 6 and other steel supports 7 Axial energy dissipation support.

Example 2:

The cross-section of the core energy-dissipating structure has a cross-shaped axisymmetric geometry, and its symmetry axis is the axial direction of the steel damper. The cross-section is narrow in the middle and wide at both ends along the axial direction. Specifically, the core energy-dissipating structure is composed of one austenitic steel plate and two ferritic steel plates. The lengths of the austenitic steel plate and the ferritic steel plate are the same in the longitudinal direction; And the connection method is shown in Figure 2 and Figure 3.

The geometric shape of the austenitic steel plate forming the energy dissipation structure of the core is shown in Figure 6. The total length of the austenitic steel plate is L=2000mm; the length L ₀ =1530mm and the width W ₀ =50mm of the central part of the steel plate (core energy-dissipating section); the thickness T of the steel plate is 16mm.

The chemical composition and mass percentage of the steel plate with austenitic structure are: 29.4% Mn, 4.3% Si, 1.4% Al, 0.049% C, 0.009% P, 0.008% S, 0.005% N, the rest is Fe and unavoidable impurity elements. The yield strength of the austenitic steel plate is 304 MPa, and the elongation at break is 52%. The microstructure of the austenitic steel plate is a single austenite structure, and the average austenite grain size is 76 μm; when entering the yield stage, the metastable austenite undergoes ε martensite transformation under the action of strain, And a reversible phase transformation between metastable austenite and strain-induced ε martensite occurs under tension-compression alternating loads.

The chemical composition and mass percentage of the steel plate with ferrite structure are: 0.30% Mn, 0.05% Si, 0.015% C, 0.05% Ti, 0.012% P, 0.006% S, 0.006% N, the rest is Fe and unavoidable impurity elements. The yield strength of the steel plate with ferrite structure is 157 MPa, and the elongation at break is 47%. The microstructure of the steel plate with ferrite structure is mainly ferrite, and the average ferrite grain size is 50 μm.

The thickness of the steel plate with the austenitic structure is the same as the thickness of the steel plate with the ferrite structure. The ratio of the sum of the cross-sectional areas of the core energy-dissipating sections of two ferritic steel plates to the cross-sectional area of the core energy-dissipating section of one austenitic steel plate is 3.2 (greater than 0.6). After welding and assembling, the distance from the connecting weld between the ferritic steel plate and the austenitic steel plate to the non-welding side of the core energy-consuming section of the two ferritic steel plates (that is, the ferrite The ratio of the width w ₀ /2) of the core energy-dissipating section of the microstructure steel plate to the thickness (t) of the ferrite microstructure steel plate is 5.0.

The peripheral constraining member is a constraining sleeve formed by a combination of steel pipes and inner concrete. There is a layer of non-adhesive material between the peripheral constraining member and the core energy dissipation structure.

Fig. 15 shows the hysteresis curves of the axial steel damper during tension-compression alternate deformation. The axial steel damper was alternately stretched-compressed for 30 cycles with a displacement of 40mm, and then alternately stretched-compressed for 4 cycles with a displacement of 45mm. No fatigue damage occurred and the bearing capacity did not attenuate. The working displacement of 40mm is equivalent to 1/50 of the axial length of the steel damper. The limit allowable displacement of the axial steel damper is greater than 40mm. The elastic stiffness is obtained from the unloading section of the hysteretic curve of the 40mm displacement, and then the yield displacement is about 3.1mm (comparing the hysteretic curves of the 40mm deformation displacement and the 45mm deformation displacement, it can be seen that after the 40mm deformation displacement, the deformation displacement with the tension-compression cycle increase, the yield displacement changes little). Calculate the ratio of the ultimate allowable displacement to the yield displacement (ie ductility) of the axial steel damper to be greater than 12.9.

Example 3:

The cross-section of the core energy-dissipating structure has a cross-shaped axisymmetric geometry, and its symmetry axis is the axial direction of the axial steel damper. The cross-section is narrow in the middle and wide at both ends along the axial direction. Specifically, the core energy-dissipating structure is composed of one austenitic steel plate and two ferritic steel plates. The lengths of the austenitic steel plate and the ferritic steel plate are the same in the longitudinal direction; And the connection method is shown in Figure 2 and Figure 3.

The geometric shape of the austenitic steel plate forming the energy dissipation structure of the core is shown in Figure 6. The total length of the austenitic steel plate is L=2000mm; the length L ₀ =1530mm and the width W ₀ =160mm of the central part of the steel plate (core energy-dissipating section); the thickness T of the steel plate is 14mm.

The chemical composition and mass percentage of the austenitic 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, the rest is Fe and unavoidable impurity elements. The yield strength of the austenitic steel plate is 229MPa, and the elongation at break is 58%. The microstructure of the austenitic steel plate is a single austenite structure, and the average austenite grain size is 126 μm; when entering the yield stage, the metastable austenite undergoes ε martensite transformation under the action of strain, And a reversible phase transformation between metastable austenite and strain-induced ε martensite occurs under tension-compression alternating loads.

The geometric shape of the ferrite structure steel plate forming the energy dissipation structure of the core is shown in Figure 7. The total length of the steel plate with ferrite structure is l=2000mm; the length l 0 of the central part of the steel plate (core energy-dissipating section) is l ₀ =1530mm, and the width w ₀ /2=200mm; the thickness t of the steel plate is 16mm.

The chemical composition and mass percentage of the steel plate with ferrite structure are: 0.18% Mn, 0.05% Si, 0.01% C, 0.04% Ti, 0.01% P, 0.006% S, 0.006% N, the rest is Fe and unavoidable impurity elements. The yield strength of the steel plate with ferrite structure is 122MPa, and the elongation at break is 50%. The microstructure of the steel plate with ferrite structure is mainly ferrite, and the average ferrite grain size is 86 μm.

The thickness of the steel plate with the austenite structure is 0.875 times the thickness of the steel plate with the ferrite structure. The ratio of the sum of the cross-sectional areas of the core energy-dissipating sections of two ferritic steel plates to the cross-sectional area of the core energy-dissipating section of one austenitic steel plate is 2.86 (greater than 0.6). After welding and assembling, the distance from the connecting weld between the ferritic steel plate and the austenitic steel plate to the non-welding side of the core energy-consuming section of the two ferritic steel plates (that is, the ferrite The ratio of the width w ₀ /2) of the core energy-dissipating section of the microstructure steel plate to the thickness (t) of the ferrite microstructure steel plate is 12.5.

The axial steel damper was alternately stretched and compressed for 30 cycles with a displacement of 40.4 mm, no fatigue damage occurred and the maximum bearing capacity remained almost unchanged. The working displacement of 40.4mm is equivalent to 1/50 of the axial length of the steel damper. The limit allowable displacement of the axial steel damper is greater than 40.4mm. The yield displacement obtained from the hysteretic curve is about 3.1mm. Calculate the ratio of the ultimate allowable displacement to the yield displacement (i.e. ductility) of the axial steel damper to be greater than 13.

Therefore, the ratio of the limit allowable displacement to the yield displacement of the axial steel damper described in this embodiment is greater than 10, and the limit allowable displacement is greater than 1/60 of the axial length of the steel damper; and, under the limit allowable displacement condition, The axial steel damper can complete at least 30 cycles of periodic alternating tension-compression plastic deformation and the bearing capacity attenuation is less than 15%.

Example 4:

The geometric shape of the austenitic steel plate forming the energy dissipation structure of the core is shown in Figure 6. The total length of the austenitic steel plate is L=2000mm; the length L ₀ =1530mm and the width W ₀ =160mm of the central part of the steel plate (core energy-dissipating section); the thickness T of the steel plate is 5mm.

The chemical composition and mass percentage of the austenitic steel plate 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 rest are Fe and unavoidable impurity elements. The yield strength of the austenitic steel plate is 288 MPa, and the elongation at break is 50%. The microstructure of the austenitic steel plate is a single austenite structure, and the average austenite grain size is 102 μm; when entering the yield stage, the metastable austenite undergoes ε martensitic transformation under the action of strain, And a reversible phase transformation between metastable austenite and strain-induced ε martensite occurs under tension-compression alternating loads.

The geometric shape of the ferrite structure steel plate forming the energy dissipation structure of the core is shown in Figure 7. The total length of the steel plate with ferrite structure is l=2000mm; the length l 0 of the central part of the steel plate (core energy-dissipating section) is l ₀ =1530mm, and the width w ₀ /2=290mm; the thickness of the steel plate is t=12mm.

The chemical composition and mass percentage of the steel plate with ferrite structure 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 rest are Fe and unavoidable impurity elements. The yield strength of the steel plate with ferrite structure is 175MPa, and the elongation at break is 31.5%. The microstructure of the steel plate with ferrite structure is mainly ferrite, and the average ferrite grain size is 192 μm.

The thickness of the steel plate with the austenitic structure is 0.416 times the thickness of the steel plate with the ferritic structure. The ratio of the sum of the cross-sectional areas of the core energy-dissipating sections of two ferritic steel plates to the cross-sectional area of the core energy-dissipating section of one austenitic steel plate is 8.7 (greater than 0.6). After welding and assembling, the distance from the connecting weld between the ferritic steel plate and the austenitic steel plate to the non-welding side of the core energy-consuming section of the two ferritic steel plates (that is, the ferrite The ratio of the width w ₀ /2) of the core energy-dissipating section of the microstructure steel plate to the thickness (t) of the ferrite microstructure steel plate is 24.2.

After the axial steel damper was alternately stretched and compressed for 30 cycles with a displacement of 33.8 mm, no fatigue damage occurred and the bearing capacity did not attenuate. The working displacement of 33.8mm is equivalent to 1/60 of the axial length of the steel damper. The limit allowable displacement of the axial steel damper is greater than 33.8mm. The elastic stiffness is obtained from the unloading section of the hysteresis curve, and then the yield displacement is about 3.0 mm. Calculate the ratio of the ultimate allowable displacement to the yield displacement (ie ductility) of the axial steel damper to be greater than 11.2.

Embodiment 5～8:

The core energy-dissipating structure is composed of an austenitic steel plate and a ferritic steel plate, the austenitic steel plate and the ferritic steel plate have the same longitudinal length; the ferrite steel plate is perpendicular to the austenitic The ferritic steel plate and the austenitic steel plate are closely connected by welding, the weld is parallel to the axial direction of the axial steel damper, and the connecting weld is located on the austenitic steel plate.

The geometric shape of the austenitic steel plate forming the energy dissipation structure of the core is shown in Figure 6. The total length of the austenitic steel plate is L=2000mm; the length L ₀ =1530mm and the width W ₀ =80mm of the central part of the steel plate (core energy-dissipating section); the thickness T of the steel plate is 16mm.

The thickness of the steel plate with the austenitic structure is the same as the thickness of the steel plate with the ferrite structure. The ratio of the cross-sectional area of the core energy-dissipating section of the ferritic steel plate to the cross-sectional area of the core energy-consuming section of the austenitic steel plate is 1.0 (greater than 0.6). After welding and assembling, the distance from the connecting weld between the ferritic steel plate and the austenitic steel plate to the non-welded side of the core energy-consuming section of the ferritic steel plate (that is, the distance between the ferritic steel plate The ratio of the width w ₀ /2) of the core energy-dissipating section to the thickness (t) of the ferrite steel plate is 5.0.

The main chemical composition (the steel inevitably contains traces of P, S, N and other impurity elements) and mechanical properties of the steel plate with austenitic structure are shown in Table 1. The microstructure of the steel plate with austenitic structure is a single austenite structure; when entering the yield stage, the metastable austenite undergoes ε-martensitic transformation under the action of strain, and under the action of tension-compression alternating load A reversible phase transformation between metastable austenite and strain-induced ε martensite occurs. The average austenite grain size of the steel plate with austenitic structure is shown in Table 1.

The main chemical composition (the steel inevitably contains traces of P, S, N and other impurity elements) and mechanical properties of the steel plate with ferrite structure are shown in Table 1. The microstructure of the steel plate with ferrite structure is mainly ferrite structure. The average ferrite grain size of the steel plate with ferrite structure is shown in Table 1.

Table 1

In the above embodiments, the yield displacement, the limit allowable displacement, and the ratio between the limit allowable displacement and the yield displacement of the axial steel damper are shown in Table 2. Under the limit allowable displacement condition, the axial steel dampers have completed at least 30 cycles of cyclic tension-compression plastic deformation without fatigue damage, and the bearing capacity of the steel dampers has not attenuated.

Table 2

the	屈服位移(μm)Yield displacement (μm)	极限允许位移(μm)Limit allowable displacement (μm)	极限允许位移与屈服位移之比Ratio of limit allowable displacement to yield displacement
实施例5Example 5	3.13.1	＞38.2>38.2	＞12.3>12.3
实施例6Example 6	3.03.0	33.833.8	11.211.2
实施例7Example 7	3.13.1	＞34.2>34.2	＞11.0>11.0
实施例8Example 8	3.03.0	35.835.8	11.911.9

Therefore, in the above-mentioned 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; and, under the condition of limit allowable displacement Next, the axial steel damper can complete at least 30 cycles of periodic alternating tension-compression plastic deformation and the bearing capacity attenuation is less than 15%.

Embodiment 9:

The core energy-dissipating structure is composed of an austenitic steel plate and a ferritic steel plate, the austenitic steel plate and the ferritic steel plate have the same longitudinal length; the ferrite steel plate is perpendicular to the austenitic The ferrite steel plate and the austenitic steel plate are closely connected by welding, the weld is parallel to the axial direction of the steel damper, and the connecting weld is located on the austenitic steel plate.

The geometric shape of the austenitic steel plate forming the energy dissipation structure of the core is shown in Figure 6. The total length of the steel plate with austenitic structure L=2000mm; the length L ₀ =1530mm and the width W ₀ =100mm of the central part of the steel plate (ie the core energy-dissipating section); the thickness T of the steel plate=16mm.

The geometric shape of the ferrite structure steel plate forming the energy dissipation structure of the core is shown in Figure 7. The total length of the steel plate with ferrite structure l=2000mm; the length l 0 of the central part of the steel plate (ie the core energy-dissipating section) l ₀ =1530mm, the width w ₀ /2=65mm; the thickness of the steel plate t=16mm.

The thickness of the steel plate with the austenitic structure is the same as the thickness of the steel plate with the ferrite structure. The ratio of the cross-sectional area of the core energy-dissipating section of the ferritic steel plate to the cross-sectional area of the core energy-consuming section of the austenitic steel plate is 0.65 (greater than 0.6). After welding and assembling, the distance from the connecting weld between the ferritic steel plate and the austenitic steel plate to the non-welded side of the core energy-consuming section of the ferritic steel plate (that is, the distance between the ferritic steel plate The ratio of the width w ₀ /2) of the core energy-dissipating section to the thickness (t) of the ferrite steel plate is about 4.1.

The chemical composition and mass percentage of the steel plate with austenitic structure are: 29.4% Mn, 4.3% Si, 1.4% Al, 0.049% C, 0.009% P, 0.008% S, 0.005% N, the rest is Fe and unavoidable impurity elements. The average austenite grain size of the austenitic structure steel plate is 76 μm. The yield strength of the austenitic steel plate is 304 MPa, and the elongation at break is 52%. The microstructure of the austenitic steel plate is a single austenite structure; when entering the yield stage, the metastable austenite undergoes ε martensite transformation under the action of strain and the α′ martensite transformation is suppressed, And a reversible phase transformation between metastable austenite and strain-induced ε martensite occurs under tension-compression alternating loads.

The peripheral constraining member is a constraining sleeve formed by a combination of steel pipes and inner concrete. There is a layer of non-adhesive material between the peripheral constraining member and the core energy-dissipating structure to eliminate friction between the peripheral constraining member and the core energy-dissipating structure.

The axial steel damper was alternately stretched and compressed for 30 cycles with a displacement of 40 mm, no fatigue damage occurred and the maximum bearing capacity remained almost unchanged. The working displacement of 40mm is equivalent to 1/50 of the total length of the steel damper. The limit allowable displacement of the axial steel damper is greater than 40mm. The yield displacement is obtained from the hysteretic curve of the 40mm displacement to be about 3.8mm. Calculate the ratio of the ultimate allowable displacement to the yield displacement (i.e. ductility) of the axial steel damper to be greater than 10.5.

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; and, the limit allowable displacement condition Next, the axial steel damper can complete at least 30 cycles of periodic alternating tension-compression plastic deformation and the bearing capacity attenuation is less than 15%.

Comparative example 1:

A buckling-resistant energy-dissipating support is composed of a core energy-dissipating structure and peripheral restraining members.

The cross-section of the core energy-dissipating structure has a cross-shaped axisymmetric geometry, and its symmetry axis is the axial direction of the energy-dissipating support. The cross-section is narrow in the middle and wide at both ends along the axial direction. Specifically, the core energy-dissipating structure is composed of one steel plate with wide austenite structure and two steel plates with narrow austenite structure, and the three steel plates with austenitic structure have the same longitudinal length; the two steel plates with narrow austenite structure Placed above and below the wide austenitic structure steel plate, with the longitudinal centerline of the wide austenitic structure steel plate as the axis of symmetry; the three austenitic structure steel plates are closely connected by welding, and the welds are parallel to the anti-buckling energy dissipation The axis direction of the support.

The geometric shape of the steel plate with wide austenite structure is shown in FIG. 6 . The total length of the wide austenite steel plate is L=2000mm; the length L ₀ of the central part of the steel plate is 1530mm, the width W ₀ is 160mm; the thickness of the steel plate is T=16mm.

The geometry of the steel plate with narrow austenitic structure is shown in FIG. 7 . The total length of the narrow austenitic steel plate is l=2000mm; the length of the central part of the steel plate is l ₀ =1530mm, the width w ₀ /2=80mm; the thickness of the steel plate is t=16mm.

The chemical compositions of the wide and narrow austenitic steel plates are exactly the same, and the mass percentages of the chemical compositions are: 29.4% Mn, 4.3% Si, 1.4% Al, 0.049% C, 0.009% P, 0.008% S, 0.005% N, the rest is Fe and unavoidable impurity elements. The yield strength of the austenitic steel plate is 304 MPa, and the elongation at break is 52%. The microstructure of the austenitic steel plate is a single austenite structure, and the average austenite grain size is 76 μm; when entering the yield stage, the metastable austenite undergoes ε martensite transformation under the action of strain, And a reversible phase transformation between metastable austenite and strain-induced ε martensite occurs under tension-compression alternating loads.

The anti-buckling energy-dissipating support undergoes fatigue failure after periodic alternating tension-compression with a displacement of 51.4mm for about 30 cycles (the maximum bearing capacity remains basically unchanged during the fatigue deformation process). The working displacement of 51.4mm is equivalent to 1/39 of the total length of the support. The limit allowable displacement of the anti-buckling energy-dissipating support is about 51.4mm. The yield displacement obtained from the hysteretic curve is about 7.8mm. The ratio of the ultimate allowable displacement to the yield displacement (i.e. the ductility) of the calculated buckling-resistant energy-dissipating brace is about 6.6.

Therefore, although the anti-buckling energy-dissipating brace described in this comparative example has a larger limit allowable displacement, the yield displacement is also relatively large, which makes the ratio of the limit allowable displacement to the yield displacement significantly smaller than 10.

Comparative example 2:

The cross-section of the core energy-dissipating structure has a cross-shaped axisymmetric geometry, and its symmetry axis is the axial direction of the energy-dissipating support. The cross-section is narrow in the middle and wide at both ends along the axial direction. Specifically, the energy-dissipating structure of the core is composed of one wide ferrite steel plate and two narrow ferrite steel plates, the three ferrite steel plates have the same longitudinal length; the two narrow ferrite steel plates They are respectively placed above and below the wide ferrite steel plate, with the longitudinal centerline of the wide ferrite steel plate as the axis of symmetry; the three ferrite steel plates are closely connected by welding, and the welds are parallel to the buckling resistance Axial direction that can be supported.

The geometric shape of the steel plate with wide ferrite structure is shown in FIG. 6 . The total length L of the steel plate with wide ferrite structure is 2000 mm; the length L ₀ of the central part of the steel plate is 1530 mm, the width W ₀ is 160 mm; the thickness T of the steel plate is 16 mm.

The geometric shape of the steel plate with narrow ferrite structure is shown in FIG. 7 . The total length of the narrow ferrite structure steel plate is l=2000mm; the length of the central part of the steel plate is l ₀ =1530mm, the width w ₀ /2=80mm; the thickness of the steel plate is t=16mm.

The chemical compositions of the wide and narrow ferrite structure steel plates are exactly the same, and the mass percentages 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, the rest is Fe and unavoidable impurity elements. The yield strength of the steel plate with ferrite structure is 157 MPa, and the elongation at break is 47%. The microstructure of the steel plate with ferrite structure is mainly ferrite structure, and the average ferrite grain size is 50 μm.

The anti-buckling energy-dissipating brace undergoes fatigue failure within less than 30 cycles of alternate tension-compression with a displacement of 33 mm. The 33mm working displacement is approximately equivalent to 1/60 of the total length of the support. Therefore, the limit allowable displacement of the anti-buckling energy-dissipating support described in this comparative example is less than 33 mm, that is, less than 1/60 of the axial length of the core energy-dissipating structure.

Comparative example 3:

The geometric shape of the ferrite structure steel plate forming the energy dissipation structure of the core is shown in Figure 7. The total length of the steel plate with ferrite structure l=2000mm; the length l 0 of the central part of the steel plate (ie the core energy-dissipating section) l ₀ =1530mm, the width w ₀ /2=54mm; the thickness of the steel plate t=16mm.

The thickness of the steel plate with the austenitic structure is the same as the thickness of the steel plate with the ferrite structure. The ratio of the cross-sectional area of the core energy-dissipating section of the ferritic steel plate to the cross-sectional area of the core energy-consuming section of the austenitic steel plate is 0.54 (less than 0.6). After welding and assembling, the distance from the connecting weld between the ferritic steel plate and the austenitic steel plate to the non-welded side of the core energy-consuming section of the ferritic steel plate (that is, the distance between the ferritic steel plate The ratio of the width w ₀ /2) of the core energy-dissipating section to the thickness (t) of the ferrite steel plate is about 3.4.

The fatigue failure of the axial steel damper occurs after the periodic alternating tension-compression with a displacement of 42 mm for nearly 30 cycles. The limit allowable displacement of the axial steel damper is about 42mm. The yield displacement is obtained from the hysteretic curve of the displacement of 42mm to be about 4.5mm. Calculate the ratio of the ultimate allowable displacement to the yield displacement (i.e. ductility) of the axial steel damper to be about 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.

The above descriptions of the embodiments are for those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments, and apply the general principles described here to other embodiments without creative effort. Therefore, the present invention is not limited to the above-mentioned embodiments. Improvements and modifications made by those skilled in the art according to the disclosure of the present invention without departing from the scope of the present invention should fall within the protection scope of the present invention.

Claims

A core energy-dissipating structure, used for an axial steel damper, plays a role in absorbing external shock energy when the axial steel damper is subjected to periodic alternating tension-compression plastic deformation, and is characterized in that,

The core energy-dissipating structure includes at least one steel plate with austenitic structure and one steel plate with ferritic structure, and the steel plate with ferritic structure must and can only be adjacent to the steel plate with austenitic structure and connected by welding , and the connecting weld between the austenitic structure steel plate and the ferrite structure steel plate is parallel to the axial direction of the core energy dissipation structure;

The microstructure of the austenitic structure steel plate is composed of metastable austenite and thermally induced ε martensite with a volume fraction of no more than 10%, and the average grain size of the metastable austenite is no more than 400 μm. During tensile or compressive plastic deformation, the metastable austenite of the austenitic steel plate induces the ε martensitic transformation under the action of strain and the α′ martensitic transformation is suppressed; - During compression plastic deformation, a reversible phase transformation between austenite and strain-induced ε martensite occurs inside the steel plate with austenitic structure;

The microstructure of the ferritic steel plate is mainly ferrite, and the average grain size of ferrite is not more than 200 μm;

The yield strength of the austenitic steel plate is not less than 220MPa, and the elongation at break is not less than 40%, and the yield strength of the steel plate with ferrite structure is less than 180MPa, and the elongation at break is not less than 30%;

The thickness of the austenitic steel plate is more than 0.4 times the thickness of the ferritic steel plate;

The ratio of the sum of the cross-sectional areas of the core energy-dissipating sections of all ferritic steel plates to the sum of the cross-sectional areas of the core energy-dissipating sections of all austenitic steel plates is not less than 0.6.
The core energy-dissipating structure according to claim 1, wherein when the steel plates with ferrite structures are different from each other and are adjacently connected with steel plates with austenite structures at both sides, the steel plates with ferrite structures and steel plates with The ratio of the distance between the connecting welds between adjacent austenitic steel plates to any non-welding side of the core energy-consuming section of the ferritic steel plates to the thickness of the ferritic steel plates is not greater than 25.
The core energy-dissipating structure according to claim 1 or 2, characterized in that if the cross-sectional geometry of the ferritic steel plate or austenitic steel plate remains unchanged along the length direction, the ferrite The core energy-consuming section of the steel plate with the ferrite structure or the steel plate with the austenite structure is the full length of the steel plate with the ferrite structure or the steel plate with the austenite structure;

If the cross-sectional geometry of the steel plate with ferrite structure or steel plate with austenite structure presents the characteristics of wide ends and narrow middle along the length direction, the core energy-consuming section of the steel plate with ferrite structure or steel plate with austenite structure It is the narrow part in the middle of the steel plate with ferrite structure or steel plate with austenite structure.
The core energy-dissipating structure according to claim 1, wherein the mass percentages of the chemical components of the austenitic steel plate are: 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%, the rest is Fe and unavoidable impurity elements, among them, Al, Ni and Cu The mass percentage also satisfies the following relationship: Ni/Cu≥0.25 and Al+0.4Ni+0.25Cu≤3.5%.
The core energy-dissipating structure according to claim 1, characterized in that, the mass percentages of the chemical composition of the ferritic steel plate are: 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 rest are Fe and unavoidable impurity elements.
The core energy dissipation structure according to claim 1, wherein the cross section of the core energy dissipation structure is selected as an axisymmetric geometry.
An axial steel damper, characterized in that it comprises the core energy-dissipating structure according to any one of claims 1-6 and peripheral constraining members, and the peripheral constraining members play a role in laterally restraining the core energy-dissipating structure. Displacement is constrained to prevent buckling instability of the energy-dissipating structure of the core.
An axial steel damper according to claim 7, characterized in that, the peripheral constraining member is selected as a constraining sleeve formed by a combination of steel pipe and inner concrete, or a reinforced concrete constraining sleeve, or a pure steel type Structural constraints.
The axial steel damper according to claim 7, wherein the ratio of the limit allowable displacement to the yield displacement of the axial steel damper is not less than 10, and the limit allowable displacement is not less than the axial steel damper 1/60 of the length of the damper; and, under the limit allowable displacement condition, the axial steel damper can complete at least 30 cycles of periodic alternating tension-compression plastic deformation and the bearing capacity attenuation is less than 15%.
The application of the axial steel damper according to claim 7, characterized in that the axial steel damper is used alone or combined with other steel supports to form an axial energy dissipation support, installed in buildings or structures, and The beam-column main structure of a building or structure is connected to form a whole, which plays a role in dissipating external vibration energy.