CN110397175A - A kind of SMA negative stiffness damping device - Google Patents

Abstract

The present invention relates to a kind of SMA negative stiffness damping devices.The SMA negative stiffness damping device includes upper base plate, lower seat board and the sliding block between upper and lower seat board, the downside of the upper base plate has lower convex globoidal, the upper side of the lower seat board has upper convex globoidal, lower cancave cambered surface of the upper side of the sliding block with the lower convex globoidal male-female engagement with upper base plate, downside have the upper cancave cambered surface with the upper convex globoidal male-female engagement of lower seat board, and the damping device further includes the SMA rope being looped around between upper base plate and lower seat board, for being pressed on upper base plate and lower seat board on sliding block.SMA negative stiffness damping device of the invention has self-resetting capability, and SMA rigging has the ability for restoring self-deformation, this ability, which to subtract damping device, can restore self-deformation.SMA negative stiffness damping device forms negative stiffness effects using the lower convex globoidal of upper base plate, the convex cambered surface of lower seat board, reduces the internal stress of damping device substructure.

Description

A kind of SMA negative stiffness damping device

technical field

The invention relates to a shock absorbing device, in particular to an SMA negative stiffness shock absorbing device.

Background technique

Since the 1960s, seismic isolation and energy consumption shock absorption technology has gradually attracted the attention of countries all over the world and has been widely used in building structures and bridge structures. Seismic isolation and shock absorption technology is to separate the structure from the ground movement or bearing movement during the earthquake to the greatest extent through the shock isolation and shock absorption device, thereby greatly reducing the seismic action transmitted to the upper structure. A large number of theoretical studies and experience of some seismic damage in isolation projects show that isolation and energy dissipation shock absorption technology is one of the most stable and effective control technologies so far. The engineering structure has withstood the test of strong earthquakes, which proves the effectiveness of this passive control technology. The shock absorption and isolation technology has also been widely used in the reinforcement and reconstruction of buildings and bridge structures. With the earthquake in recent years Frequent occurrence, earthquake-resistant products related to bridges and buildings have been developed rapidly.

Superelastic shape memory alloys (Shape Memory Alloys, SMA) are applied to seismic isolation bridges, which can effectively reduce the maximum relative displacement between pier beams, reduce residual deformation, and increase additional energy dissipation capacity. Scholars at home and abroad have proposed a large number of SMA limit devices and SMA-based shock-absorbing and isolating devices, which have greatly improved the self-restoring ability of bridges. However, since the SMA members increase the connection stiffness between the pier and the beam, the internal force response of the substructure under the action of the ground motion increases significantly. How to reduce the internal force of the substructure has become a major problem to be solved for bridges with SMA isolation systems.

Contents of the invention

In order to solve the above problems, the present invention provides an SMA negative stiffness damping device to solve the technical problem that the SMA damping device in the prior art is easily damaged due to large internal force response.

The technical scheme of a kind of SMA negative stiffness damping device of the present invention is:

A kind of SMA negative stiffness damping device comprises an upper seat plate, a lower seat plate and a slider between the upper and lower seat plates, the lower side of the upper seat plate has a downward convex arc surface, and the upper side of the lower seat plate has Convex arc surface, the upper side of the slider has a concave arc surface that is concavo-convex with the arc top part of the convex arc surface of the upper seat plate, and the lower side has a concavo-convex surface with the arc top part of the convex arc surface of the lower seat plate Matched with the upper concave arc surface, the shock absorbing device also includes an SMA cable that wraps around between the upper seat plate and the lower seat plate and is used to press the upper seat plate and the lower seat plate on the slider.

There is also a limit SMA cable between the upper seat plate and the lower seat plate. When the upper and lower seat plates do not slide relative to each other, the limit SMA cable is in a relaxed state. When the upper and lower seat plates relatively slide, the limit SMA cable is used for tension It is used to limit the sliding position of the upper and lower seat plates.

The position-limiting SMA cable is connected with the upper and lower seat plates through a spherical hinge structure.

The spherical joint structure includes ball joints arranged at both ends of the position-limiting SMA cable, and ball joint seats fixedly connected to the upper and lower seat plates.

The ball socket includes two detachably connected single bodies.

The slider is a cylindrical block, the edge of the lower convex arc surface of the upper seat plate is round, and the edge of the upper convex arc surface of the lower seat plate is round.

There are multiple SMA cables, some of the multiple SMA cables are horizontal SMA cables arranged in parallel and at intervals, and the rest are longitudinal SMA cables arranged in parallel and at intervals.

The arc of the lower convex arc surface of the upper seat plate is equal to the arc of the upper convex arc surface of the lower seat plate.

The beneficial effects of the present invention are:

In the SMA negative stiffness damping device of the present invention, the upper seat plate is connected to the building structure, and the lower seat plate is connected to the foundation structure. The gravity of the structure carried by the upper seat plate will act on the upward convex arc surface, and the gravity load will be generated along the upper convex arc surface. The component force along the tangential direction of the upper convex arc surface provides the force for the slider to slide down, and the friction between the slider and the upper convex arc surface prevents the slider from sliding down. When the sliding force is greater than the frictional force, the difference between the two helps the slider deviate from the equilibrium position. Through the cooperation of the upper concave arc surface and the upper convex arc surface, the slider will slide on the upper seat plate, so that the shock absorber will generate negative stiffness.

The SMA negative stiffness shock-isolation bearing of the present invention has self-resetting ability, and the SMA cable has the ability to recover its own deformation, which enables the shock-absorbing device to recover its own deformation. The SMA negative stiffness shock absorber utilizes the lower convex arc surface of the upper seat plate and the upper convex arc surface of the lower seat plate to form a negative stiffness effect to reduce the internal stress of the lower structure of the shock absorber.

Furthermore, the limit SMA cable effectively limits the maximum displacement of the shock absorbing device, so that the displacement between the pier beams is reduced, which can effectively prevent the occurrence of earthquake damage caused by falling beams.

Furthermore, the parallel connection of the SMA negative stiffness damping device of the present invention and the damper can achieve the dual control goal of simultaneously reducing the internal force and displacement of the structure.

Further, the position-limiting SMA cable is connected with the upper seat plate and the lower seat plate through a spherical hinge structure, which is convenient for replacing the position-limiting SMA cable.

Description of drawings

Fig. 1 is the structural representation of SMA negative stiffness damping device of the present invention;

Fig. 2 is the exploded view of SMA negative stiffness damping device of the present invention;

Fig. 3 is a state diagram when the upper and lower seat plates do not slide relative to each other in the SMA negative stiffness damping device of the present invention;

Fig. 4 is a state diagram when upper and lower seat plates slide relative to each other in the SMA negative stiffness damping device of the present invention;

Fig. 5 is the structural representation of the spherical joint structure in the SMA negative stiffness damping device of the present invention;

Fig. 6 is a schematic structural view of the spherical joint ball head seat in the SMA negative stiffness damping device of the present invention;

Fig. 7 is the structural schematic view of the limit SMA cable and the ball head in the SMA negative stiffness damping device of the present invention;

Fig. 8 is a sectional view along the II-II direction in Fig. 7;

Fig. 9 is a sectional view along the I-I direction in Fig. 7;

Fig. 10 is a connection state diagram of the sleeve and the limit SMA in the SMA negative stiffness damping device of the present invention;

In the figure: 1-upper seat plate; 11-lower convex arc surface; 2-lower seat plate; 21-upper convex arc surface; 3-SMA cable; 31-transverse SMA cable; 32-longitudinal SMA cable; 4-slider; 41-concave arc surface; 5-limiting SMA cable; 51-SMA wire; 6-ball head; 61-perforation; 7-ball seat; Two; 8-cable inner sleeve; 9-cable outer sleeve.

Detailed ways

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

Specific embodiment one of the SMA negative stiffness damping device of the present invention, as shown in Figure 1 and Figure 2, includes an upper seat plate 1, a lower seat plate 2 and a slider 4 positioned between the upper and lower seat plates, and the upper seat plate 1 and the lower seat plate 2 are rectangular plates, and the slide block 4 is a columnar structure. The central position of the lower side of the upper seat plate 1 has a lower convex arc surface 11, and the upper side of the lower seat plate 2 has an upper convex arc surface 21, and the edges of the upper convex arc surface 21 and the lower convex arc surface 11 are all circular, and the upper seat plate The projection of the lower convex arc surface 11 of 1 on the lower seat plate 2 coincides with the upper convex arc surface 21 of the lower seat plate 2. The upper side of the slide block 4 has a concave arc surface 41 that is concave-convexly matched with the arc top part of the convex arc surface 11, and the lower side has an upper concave arc surface that is concave-convexly matched with the arc top part of the convex arc surface 21, so that the sliding The block 4 can slide along the lower convex arc surface 11 and the upper convex arc surface 21 .

Referring to Fig. 3 and Fig. 4, the edge of the upper seat plate 1 has a folded edge bent downward, and the edge of the lower seat plate 2 has a folded edge bent upward, which is used to limit the slider 4 to prevent sliding. Block 4 slides out of the gap between upper seat plate 1 and lower seat plate 2 .

In this embodiment, the SMA negative stiffness shock absorbing device further includes an SMA cable 3 that surrounds between the upper seat plate 1 and the lower seat plate 2 and is used to press the upper seat plate 1 and the lower seat plate 2 on the slider 4 . There are multiple SMA cables 3, and each SMA cable 3 is composed of seven SMA wires with a diameter of d. Among the multiple SMA cables 3, some are transverse SMA cables 31 arranged in parallel and spaced intervals, and the remaining parts are longitudinal SMA cables arranged in parallel and spaced intervals. Cable 32. The transverse SMA cable 31 and the longitudinal SMA cable 32 can generate force in the circumferential direction of the rectangular upper seat plate and the lower seat plate.

The SMA negative stiffness damping device also includes a plurality of space-limiting SMA cables 5 connected between the upper seat plate 1 and the lower seat plate 2 , and the plurality of space-limiting SMA cables 5 are evenly distributed in the circumferential direction with the point on the axis of the slider 4 as the center. As shown in FIG. 7 and FIG. 8 , each limiting SMA cable 5 is composed of seven SMA wires 51 with a diameter of d. As shown in FIG. 9 , the ball head 6 has a perforation 61 through which the SMA wires 51 pass. The end of the limit SMA cable 5 is covered with a cable inner sleeve 8, and a cable outer sleeve 9 is connected between the two cable inner sleeves 8, as shown in Figure 10, so that the limit SMA cable is connected end to end. The limit SMA cable 5 is connected with the upper seat plate 1 and the lower seat plate 2 through a spherical hinge structure. Specifically, as shown in FIG. 5 and FIG. 6 , the ball joint structure includes a ball head 6 connected to both ends of the position-limiting SMA cable 5 and a ball head seat 7 fixed on the upper seat plate 1 and the lower seat plate 2 . The ball seat 7 on the upper seat plate 1 is fixed on the outside of the lower convex arc surface 11, and the ball seat 7 on the lower seat plate is fixed on the outside of the upper convex arc surface 21.

The ball head seat 7 includes a ball head seat unit one 71 and a ball head seat unit two 72 which are detachably connected, and the ball head seat unit one 71 and the ball head seat unit two 72 are fixed on the upper seat plate 1 and the lower seat by bolts plate 2. There is an accommodating chamber for accommodating the ball head 6 between the ball head unit one 71 and the ball head unit two 72, and the ball head unit two 72 has a threading hole communicating with the accommodating chamber for the limit SMA cable. 5 through.

In this embodiment, the limiting SMA cable 5 is U-shaped, and the U-shaped limiting SMA cable 5 is in a relaxed state when the upper seat plate 1 and the lower seat plate 2 do not slide relative to each other. When the upper seat plate 1 and the lower seat plate 2 slide relative to each other, the limit SMA cable 5 is tensioned to limit the sliding position of the upper seat plate 1 and the lower seat plate 2 .

The principle of the SMA negative stiffness shock absorber of the present invention is: under normal use, the shock absorber evenly transmits the load on the upper part of the structure to the structure, and plays the role of a common support. When a small or medium earthquake occurs, the upper seat plate 1 and the slider 4, and the lower seat plate 2 and the slider 4 slide relative to each other, which consumes energy by friction and prolongs the structural period, thereby achieving a good shock isolation effect. When a large earthquake occurs, in addition to the above-mentioned frictional sliding, the SMA cable 3 wrapped between the upper seat plate 1 and the lower seat plate 2 will participate in hysteretic energy consumption, and use its superelasticity to provide restoring force, so as to reduce the structural response, The purpose of limiting the displacement of the support; at the same time, the limit SMA cable 5 is tensioned to limit the sliding displacement of the upper seat plate 1 and the lower seat plate 2.

In the SMA negative stiffness damping device of the present invention, the upper seat plate is connected to the building structure, and the lower seat plate is connected to the foundation structure. The gravity of the structure carried by the upper seat plate will act on the upward convex arc surface, and the gravity load will be generated along the upper convex arc surface. The component force along the tangential direction of the upper convex arc surface provides the force for the slider to slide down, and the friction between the slider and the upper convex arc surface prevents the slider from sliding down. When the sliding force is greater than the frictional force, the difference between the two helps the slider deviate from the equilibrium position. Through the cooperation of the upper concave arc surface and the upper convex arc surface, the slider will slide on the upper seat plate, so that the shock absorber will generate negative stiffness.

In this embodiment, the radius of the lower convex arc surface 11 of the upper seat plate 1 and the upper convex arc surface 21 of the lower seat plate 2 depends on the size of the negative stiffness required by the SMA negative stiffness shock absorber, and the SMA negative stiffness shock absorber requires The greater the negative stiffness, the larger the radius of the lower convex arc surface 11 of the upper seat plate 1 and the upper convex arc surface 21 of the lower seat plate 2 . The height of the slider 4 is related to the self-resetting capability of the SMA negative stiffness shock absorber, the higher the slider 4 is, the stronger the self-reset capability of the SMA negative stiffness shock absorber. The length of the SMA cable 3 is determined according to the layout of the SMA cable 3 and the initial tension. The cross-sectional area of the SMA cable 3 is determined according to the initial tension, the arrangement form and the required restoring force.

The SMA negative stiffness shock absorbing device of the present invention has self-resetting ability, and the SMA cable 3 has the ability to restore its own deformation, which enables the shock absorbing device to restore its own deformation. The SMA negative stiffness damping device uses the lower convex arc surface 11 of the upper seat plate 1 and the upper convex arc surface 21 of the lower seat plate 2 to form a negative stiffness effect to reduce the internal stress of the lower structure of the shock absorber. The limit SMA cable 5 effectively limits the maximum displacement of the shock absorbing device, so that the displacement between the pier beams is reduced, which can effectively prevent the occurrence of earthquake damage caused by falling beams. The SMA negative stiffness damping device of the present invention is connected in parallel with the damper, which can achieve the dual control goal of simultaneously reducing the internal force and displacement of the structure. The limit SMA cable 5 is connected with the upper seat plate 1 and the lower seat plate 2 through a spherical hinge structure, which is convenient for replacing the limit SMA cable 5 .

The second specific embodiment of the SMA negative stiffness shock absorber of the present invention differs from the first specific embodiment of the SMA negative stiffness shock absorber in that the lower side of the upper seat plate in this embodiment has an elliptical downward convex boundary. Arc surface, the upper side of the lower seat plate has an upward convex arc surface whose boundary is an ellipse. In other embodiments, the boundary between the lower convex arc surface and the upper convex arc surface can also be in other shapes, as long as the slider can slide between the upper convex arc surface and the lower convex arc surface. Others are the same as those in Embodiment 1, and will not be repeated here.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the present invention, some improvements and replacements can also be made, these improvements and replacements It should also be regarded as the protection scope of the present invention.

Claims (8)

1. A kind of SMA negative stiffness shock absorber, it is characterized in that: comprise upper seat plate, lower seat plate and be positioned at the slide block between upper and lower seat plate, the lower side of described upper seat plate has downward convex arc surface, described The upper side of the lower seat plate has an upward convex arc surface, the upper side of the slider has a lower concave arc surface that is concave-convex to match the lower convex arc surface of the upper seat plate, and the lower side has a concave-convex surface that matches the upper convex arc surface of the lower seat plate. The upper concave arc surface, the shock absorbing device also includes an SMA cable that surrounds between the upper seat plate and the lower seat plate and is used to press the upper seat plate and the lower seat plate on the slider. 2. The SMA negative stiffness shock absorbing device according to claim 1, characterized in that: a limit SMA cable is also provided between the upper seat plate and the lower seat plate, and the limit SMA cable is installed when the upper and lower seat plates do not slide relative to each other. In the relaxed state, when the upper and lower seat plates slide relative to each other, the limit SMA cable is tensioned to limit the sliding position of the upper and lower seat plates. 3. The SMA negative stiffness damping device according to claim 2, characterized in that: the position-limiting SMA cable is connected to the upper and lower seat plates through a spherical hinge structure. 4. The SMA negative stiffness shock absorber according to claim 3, characterized in that: the spherical joint structure includes ball joints arranged at both ends of the limit SMA cable, ball joints fixedly connected to the upper and lower seat plates . 5. The SMA negative stiffness shock absorber according to claim 4, characterized in that: the ball seat comprises two detachably connected units. 6. The SMA negative stiffness damping device according to any one of claims 1 to 5, characterized in that: the slider is a cylindrical block, and the edge of the lower convex arc surface of the upper seat plate is circular, so The edge of the convex arc surface of the lower seat plate is circular. 7. The SMA negative stiffness damping device according to any one of claims 1 to 5, characterized in that: the SMA cables have multiple pieces, and some of the multiple SMA cables are transverse SMA cables arranged in parallel at intervals, and the remaining Some are longitudinal SMA cables arranged in parallel intervals. 8 . The SMA negative stiffness shock absorber according to any one of claims 1 to 5 , wherein the arc of the lower convex arc surface of the upper seat plate is equal to the arc of the upper convex arc surface of the lower seat plate. 9 .