An SMA plate damper and its seismic resistance method for self-resetting rocking structures

Abstract

This invention discloses an SMA plate damper and its seismic resistance method for self-resetting rocking structures. The damper includes an SMA core plate, strip heating units, C-shaped strips, and a buckling restraint plate. The SMA core plate is martensitic and dumbbell-shaped with openings at both ends. The C-shaped strips are arranged on both sides of the SMA core plate along its thickness direction, extending in the same direction as the SMA core plate. Two strip heating units are respectively arranged in the narrow grooves of the two C-shaped strips and are in close contact with the SMA core plate. The C-shaped strips and the buckling restraint plate provide buckling restraint for the SMA core plate. This invention utilizes the unique temperature-performance relationship of SMA material to form a self-reinforcing SMA plate damper. When applied to a self-resetting rocking structure, it can enhance the structure's seismic resistance under the combined action of main and aftershocks.

Description

Technical Field

[0001] This invention relates to an SMA plate damper and its seismic resistance method for self-resetting rocking structures, belonging to the field of building engineering. Background Technology

[0002] Self-resetting sway structures are a typical type of recoverable functional structures. Under horizontal seismic loading, they exhibit "flag-shaped" hysteresis behavior, which can reduce or eliminate residual structural deformation under seismic loading, thus shortening post-earthquake repair time and reducing economic costs.

[0003] Because the main shock causes localized damage such as structural cracking, the stiffness of self-setting rocking structures degrades slightly after the main shock, significantly reducing their ability to resist aftershocks. Timely repair of the structure after the main shock is necessary to enhance its ability to withstand aftershocks. However, energy-dissipating components in self-setting rocking structures, such as metal dampers, which dissipate seismic input energy, enter the plastic stage during the main shock, generating significant residual deformation. This prevents them from effectively dissipating energy in a timely manner, potentially leading to greater and more difficult-to-recover damage and deformation under aftershocks. Therefore, to improve the seismic performance of self-setting rocking structures under the combined action of the main shock and aftershocks, it is necessary to develop dampers with self-reinforcing functional characteristics that can effectively dissipate seismic energy after the main shock. Summary of the Invention

[0004] Technical Objective: This invention addresses the aforementioned technical problems by proposing an SMA plate damper and its seismic resistance method for self-resetting rocking structures to resist the combined effects of main and aftershocks. Due to the excellent fatigue performance and shape memory characteristics of SMA material, the SMA plate damper can achieve functional self-reinforcement by controlling the temperature. Furthermore, the SMA plate damper uses a dumbbell-shaped SMA core plate, with the central energy-dissipating section reaching its ultimate tensile strength first, which is beneficial for fully dissipating seismic energy.

[0005] This invention adopts the following technical solution: an SMA plate damper, comprising an SMA core plate, a strip heating unit, a C-shaped strip, and a buckling restraint plate, wherein,

[0006] The SMA core plate is a martensitic phase and is processed into a dumbbell shape with end openings and a middle energy-dissipating section.

[0007] The end opening section is used for installation on the self-resetting rocking structure;

[0008] The middle energy-dissipating section has a weakened cross-section along the width direction, and the bearing capacity of the middle energy-dissipating section is lower than that of the end opening section.

[0009] The C-shaped strip includes two strips, each strip having a narrow groove and a wide groove along its thickness direction. The openings of the two C-shaped strips are positioned opposite each other on both sides of the energy-dissipating section in the middle of the SMA core board. The two wide grooves are joined together to form an installation groove that completely encloses the energy-dissipating section in the middle of the SMA core board.

[0010] The strip heating unit includes two units, with one unit placed in the narrow groove of each C-shaped strip, and the strip heating unit is in close contact with the SMA core board.

[0011] The control device includes a temperature sensor within the strip heating unit. The control device collects the temperature of the SMA core board through the temperature sensor, and then controls the heating power of the strip heating unit.

[0012] The buckling restraint plate is arranged on the outside of the SMA plate damper and fixed to the self-resetting rocking structure. Without affecting the axial deformation of the SMA core plate, it together with the C-shaped strip restrains the buckling deformation of the SMA core plate along the thickness direction.

[0013] It also includes an annular gasket, which is connected to both sides of the end opening section at the end of the SMA core board along the thickness direction of the SMA core board.

[0014] Both the C-shaped strip and the annular gasket are made of Teflon material.

[0015] The thickness of the end opening section of the SMA core board after the annular gasket is installed is equal to the thickness of the energy-dissipating section in the middle of the SMA core board after the C-shaped strip is installed.

[0016] One end of the control device is connected to the strip heating unit, and the other end is connected to the battery.

[0017] The thickness of each section of the SMA core board is consistent.

[0018] The SMA core plate is made of nickel-titanium alloy.

[0019] The present invention further discloses a seismic resistance method for a self-resetting rocking structure based on the SMA plate damper, wherein the SMA plate damper is installed at the location where the self-resetting rocking structure deforms significantly under horizontal seismic action;

[0020] During the main shock, the SMA plate damper is in the martensitic phase, undergoes plastic deformation, and dissipates seismic energy.

[0021] After the main shock, the strip heating unit is immediately activated and maintains the temperature of the SMA core plate above its austenitic phase transformation end temperature. The SMA core plate transforms from martensite to austenite, and its shape is quickly restored to eliminate plastic deformation. The strength and stiffness of the SMA plate damper are enhanced.

[0022] During aftershocks, the SMA core plate is heated and maintained at a temperature in an austenitic phase, meaning that the strength and stiffness of the SMA plate damper are stronger than during the main shock. This enhanced damper performance effectively compensates for the damage caused to the structure by the main shock, reducing the risk of more severe damage or collapse during the aftershock phase. Because the austenitic phase of SMA has superelasticity, the SMA plate damper improves the self-resetting performance of the self-resetting rocking structure during the aftershock phase.

[0023] After the main and aftershocks completely cease, the strip heating unit stops working, the SMA core plate returns to its initial shape, and the martensitic phase is restored. Beneficial effects

[0024] First, the SMA core plate of the SMA plate damper of this invention is processed into a "dumbbell shape", which ensures that the cross-sectional area of ​​the energy dissipation section in the middle is smaller than the net cross-sectional area of ​​the end opening section. This means that when the SMA core plate is under tension, the energy dissipation section in the middle reaches the ultimate tensile strength before the end opening section due to the larger tensile stress, which is beneficial for fully dissipating seismic energy.

[0025] Second, this invention effectively limits the buckling deformation of the energy-dissipating section in the middle of the SMA core plate by using buckling-restrained restraint plates and C-shaped strips. Therefore, the SMA plate damper has high tensile and compressive strength, stable hysteretic performance, and is easy to use in various structural analyses and designs, showing good application prospects.

[0026] Third. During the main shock, the SMA core plate of the SMA plate damper of the present invention is in the martensitic phase, undergoing plastic deformation, which effectively dissipates seismic energy. After the main shock, the SMA core plate transforms from the martensitic phase to the austenitic phase, and its shape is quickly restored, thereby eliminating plastic deformation in time. The strength and stiffness of the SMA plate damper are enhanced. During the aftershock, the SMA core plate is in the austenitic phase, and the strength and stiffness of the SMA plate damper are stronger than during the main shock. The enhanced performance of the damper effectively compensates for the damage caused to the structure by the main shock and reduces the risk of more severe damage or collapse of the structure during the aftershock.

[0027] Fourth. The SMA plate damper of the present invention can be installed on the surface of structural components, saving building space and having little impact on the building's functionality.

[0028] Fifth. The SMA core board of the present invention has a reasonable structure and is easy to process. Attached Figure Description

[0029] Figure 1 This is a structural diagram of the SMA plate damper of the present invention; Figure 2 This is a cross-sectional view of the C-shaped strip of the present invention;

[0030] Figure 3This is an assembly diagram of the SMA core board, C-shaped strip, and annular gasket of the present invention.

[0031] The components include: SMA core board 1; strip heating unit 2; annular gasket 3; C-shaped strip 4; and anti-buckling restraint plate 5. Implementation Method

[0032] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] Shape memory alloys (SMA) are a novel functional material possessing superelasticity and shape memory properties. SMA exists in different crystalline phases at different temperatures, corresponding to different mechanical properties. Generally, the high-temperature austenitic phase exhibits higher strength and stiffness than the low-temperature martensitic phase. Using SMA dampers in self-resetting rocking structures allows for the alteration of their mechanical properties by controlling the crystal phase of the SMA during specific seismic phases, thus achieving self-adjustment and intelligent control of the building structure's seismic performance. Therefore, effective temperature control of SMA dampers enables rapid automatic recovery and automated regulation of structural functions, enhances the structure's seismic performance during aftershocks, and reduces the risk of structural collapse.

[0034] like Figure 1 As shown: An SMA plate damper consists of an SMA core plate 1, a strip heating unit 2, an annular gasket 3, a C-shaped strip 4, an annular gasket 3, and a buckling restraint plate 5; the SMA core plate 1 is machined and is dumbbell-shaped, consisting of a middle energy dissipation section and an end perforated section.

[0035] The energy-dissipating section in the middle of the SMA core board 1 is weakened along the width direction. The weakened section is axially symmetric or centrally symmetric, so that the strength of the energy-dissipating section in the middle is less than the strength of the end opening section.

[0036] The annular gasket 3 is made of fluoropolymer and has a circular hole along the thickness direction; the annular gasket 3 is arranged on both sides of the hole section at the end of the SMA core board 1 along the thickness direction.

[0037] The buckling restraint plate 5 is machined from steel plate, arranged on the outside of the SMA plate damper and fixed to the self-resetting rocking structure. Without affecting the axial deformation of the SMA core plate, it together with the C-shaped strip 4 restrains the buckling deformation of the SMA core plate 1 along the thickness direction.

[0038] like Figure 2 As shown: The C-shaped strip 4 is made of fluoropolymer and has two grooves, one narrow and one wide, cut along its thickness direction; the strip heating unit 2 is arranged in the narrow groove of the C-shaped strip 4; the energy-consuming section in the middle of the SMA core board 1 is arranged in the wide groove of the C-shaped strip 4. The C-shaped strip plays a heat-preserving role during the heating process of the heating device.

[0039] like Figure 3 As shown: the annular gasket 3 and the C-shaped strip 4 are installed on both sides of the SMA core board in the thickness direction, and the thickness of the middle energy-dissipating section is equal to the thickness of the end opening section.

[0040] In a preferred embodiment of the present invention, the SMA core plate is made of nickel-titanium alloy.

[0041] The present invention relates to a seismic resistance method for self-resetting rocking structures using SMA plate dampers. The SMA plate dampers are installed at locations where the self-resetting rocking structure deforms significantly under horizontal seismic action. During the main shock, the SMA plate dampers are in the martensitic phase, undergoing plastic deformation and dissipating seismic energy. Because the SMA core plate is processed into a dumbbell shape, the cross-sectional area of ​​the energy-dissipating section in the middle is smaller than the net cross-sectional area of ​​the end perforated section. This ensures that when the SMA core plate is under tension, the energy-dissipating section in the middle reaches its ultimate tensile strength before the end perforated section due to the higher tensile stress, thus fully dissipating seismic energy.

[0042] After the main shock, the strip heating unit is immediately activated and maintains the temperature of the SMA core plate above its austenitic phase transformation end temperature. The SMA core plate transforms from martensite to austenite, and its shape is quickly restored to eliminate plastic deformation. The strength and stiffness of the SMA plate damper are enhanced.

[0043] During aftershocks, the SMA core plate is heated and maintained at a temperature in an austenitic phase, meaning that the strength and stiffness of the SMA plate damper are stronger than during the main shock. This enhanced damper performance effectively compensates for the damage caused to the structure by the main shock, reducing the risk of more severe damage or collapse during the aftershock phase. Because the austenitic phase of SMA has superelasticity, the SMA plate damper improves the self-resetting performance of the self-resetting rocking structure during the aftershock phase.

[0044] After the main and aftershocks completely cease, the strip heating unit stops working, the SMA core plate returns to its initial shape and recovers the martensitic phase, requiring no repair or replacement, and can continue to be used.

[0045] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations of these embodiments within the scope of the principles and technical concept of the present invention still fall within the protection scope of the present invention.

Claims

1. An SMA plate damper, characterized by, The SMA core plate is in martensite phase and is processed into dumbbell shape with an end opening section and a middle energy consumption section; The end opening section is used to be installed on the self-centering rocking structure; The middle energy consumption section is weakened in the width direction, and the bearing capacity of the middle energy consumption section is lower than that of the end opening section; The C-shaped strip includes two, each C-shaped strip is respectively provided with a narrow opening groove and a wide opening groove in the thickness direction, the openings of the two C-shaped strips are opposite to the two sides of the middle energy consumption section of the SMA core plate, and the two wide opening grooves are butted to form an installation groove for completely wrapping the middle energy consumption section of the SMA core plate; The strip-shaped heating unit includes two, one strip-shaped heating unit is arranged at the narrow opening groove of each C-shaped strip, and the strip-shaped heating unit is close to the SMA core plate; A control device is arranged outside the strip-shaped heating unit, the temperature of the SMA core plate is collected by the temperature sensor, and then the heating power of the strip-shaped heating unit is controlled; The anti-buckling restraint plate is arranged outside the SMA plate damper and is fixed to the self-centering rocking structure, and the anti-buckling restraint plate does not affect the axial deformation of the SMA core plate and restrains the buckling deformation of the SMA core plate in the thickness direction together with the C-shaped strip.

2. The SMA panel damper of claim 1, wherein, An annular gasket is further arranged and is connected to the two sides of the end opening section of the SMA core plate in the thickness direction of the SMA core plate.

3. The SMA panel damper of claim 2, wherein, The C-shaped strip and the annular gasket are both made of Teflon material.

4. The SMA panel damper of claim 2, wherein, The thickness of the SMA core plate after the annular gasket is arranged on the end opening section is equal to the thickness of the SMA core plate after the C-shaped strip is arranged on the middle energy consumption section.

5. The SMA panel damper of claim 1, wherein, One end of the control device is connected to the strip-shaped heating unit, and the other end is connected to a battery.

6. The SMA panel damper of claim 1, wherein, The thickness of each section of the SMA core plate is consistent.

7. The SMA panel damper of claim 1, wherein, The material of the SMA core plate is nickel-titanium alloy.

8. An anti-seismic method for a self-centering rocking structure based on the SMA plate damper in any one of claims 1-7, characterized in that: The SMA plate damper is installed at a position of the self-centering rocking structure where the deformation is large under horizontal seismic action; During the main earthquake, the SMA plate damper is in martensite phase and generates plastic deformation to dissipate seismic energy; because the SMA core plate is processed into dumbbell shape, the cross-sectional area of the middle energy consumption section is smaller than that of the end opening section, so that the middle energy consumption section reaches the ultimate tensile strength before the end opening section when the SMA core plate is subjected to tension, and the seismic energy is fully dissipated; After the main earthquake, the strip-shaped heating unit is immediately started, and the temperature of the SMA core plate is maintained above the austenite phase transition end temperature, the SMA core plate is converted from martensite phase to austenite phase, the shape is quickly restored to eliminate plastic deformation, and the strength and stiffness of the SMA plate damper are enhanced. In the aftershock stage, the SMA core plate is heated and maintained at a temperature to be in an austenitic phase state, that is, the strength and stiffness of the SMA plate damper are stronger than in the main shock stage, the performance of the damper is strengthened to effectively compensate for the damage caused by the main shock to the structure, and the risk of more serious damage or collapse of the structure in the aftershock stage is reduced; since the austenitic phase SMA has superelasticity, the SMA plate damper improves the self-centering performance of the self-centering rocking structure in the aftershock stage; After the main shock and the aftershock completely stop, the strip-shaped heating unit stops working, the SMA core plate returns to the initial shape, and returns to the martensitic phase.

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