Plane multidirectional bridge damping and energy consumption device with self-resetting function and restoring force calculation method of plane multidirectional bridge damping and energy consumption device

Abstract

The invention provides a plane multidirectional bridge damping energy consumption device with a self-resetting function and a restoring force calculation method thereof. The device comprises an upper movable block, a lower connecting plate system, a connecting rod system and an SMA inhaul cable system. The lower connecting plate system is composed of a lower connecting plate, a sliding bearing, a limiting check block, a fixed pulley, a double-layer fixed pulley and an anchoring plate. The connecting rod system is composed of a push plate, a first connecting rod, a sleeve bolt check block, a second connecting rod, a connecting piece and a movable pulley. The SMA inhaul cable system is composed of SMA inhaul cables, bolts and nuts, the SMA inhaul cables surround the inner sides and the outer sides of the fixed pulleys and the movable pulleys respectively, and the two ends of each SMA inhaul cable are anchored to the anchoring plates through the bolts. The upper movable blocks can push the corresponding push plates to move in any direction of the plane, the SMA inhaul cables are lengthened to achieve the damping, energy dissipation and self-resetting functions, and the limiting check blocks achieve the limiting function by limiting the movement range of the push plates. And analyzing the geometrical relationship between the movement distance of the upper movable block and the elongation of the SMA inhaul cable to obtain a calculation method of the restoring force of the device. The size of the device can be reduced, bidirectional self-resetting and limiting functions are provided, and the use efficiency of the SMA inhaul cable is improved.

Description

Technical Field

[0001] The invention relates to the technical field of bridge earthquake resistance, in particular to a planar multi-directional bridge shock absorption and energy dissipation device with a self-resetting function and a restoring force calculation method thereof. Background Art

[0002] Earthquake action is an important working condition for bridge structure design. Especially in near-fault areas, bridges are subject to large seismic displacement requirements under velocity pulse earthquakes, and the main beams and piers are prone to large relative displacements, and the relative displacements that occur are not only in a specific direction. Therefore, the shock-absorbing and energy-dissipating device not only needs to have good energy dissipation capacity, but also should have multi-directional large displacement capacity. Shape memory alloy (SMA) has good energy dissipation and deformation capacity due to its superelastic characteristics. Generally, the ultimate strain of SMA cables can reach 5% to 10%. Despite this, to achieve large displacement capacity, a longer SMA cable is still required. For example, if a relative displacement capacity of 30 cm is to be achieved, when the ultimate strain of the SMA cable is 6%, the length of the SMA cable needs to be 30 cm / 6% = 5 m, which will cause the size of the shock-absorbing and energy-dissipating device to be too large. Summary of the invention

[0003] In view of this, the object of the present invention is to provide a planar multi-directional bridge shock-absorbing and energy-dissipating device with a self-resetting function and a method for calculating its restoring force. The device has a relatively small structural size and has bidirectional self-resetting and limiting functions.

[0004] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a planar multi-directional bridge shock absorption and energy dissipation device with a self-resetting function, comprising an upper movable block (1), a lower connecting plate system, a connecting rod system and an SMA cable system; the upper movable block (1) is connected to the main beam at the top and has a rectangular cross-sectional shape; the lower connecting plate system comprises a lower connecting plate (2), a sliding bearing (21), a limit stopper (22), a fixed pulley (23), a double-layer fixed pulley (24) and an anchor plate (25); the lower connecting plate (2) has a rectangular cross-sectional shape and is connected to the main beam at the bottom. The sliding bearing (21) and the limit stopper (22) are fixedly arranged above the lower connecting plate (2) in the front, rear, left and right directions, wherein the limit stopper (22) is arranged on the inner side of the sliding bearing (21); the fixed pulley (23) and the double-layer fixed pulley (24) are fixedly arranged above the lower connecting plate (2) near four corner points, wherein the fixed pulley (23) is arranged at three corner points and the double-layer fixed pulley (24) is arranged at one corner point; the anchor plate (25) is fixedly arranged at the position where the double-layer fixed pulley (24) is arranged on the lower connecting plate (2). The connecting rod system comprises a push plate (31), a first connecting rod (32), a sleeve bolt block (33), a second connecting rod (34), a connecting piece (35) and a movable pulley (36); the first connecting rod (32) and the push plate (31) are fixed to each other, the first connecting rod (32) and the second connecting rod (34) are connected by the sleeve bolt block (33), the second connecting rod (34) and the connecting piece (35) are fixed to each other, the movable pulley (36) has a central roller, and the connecting piece (35) and the central roller are fixed to each other; the SM A cable system comprises an SMA cable (4), a nut (41) and a bolt (42); the SMA cable (4) is arranged in a ring shape, the SMA cable (4) is wrapped around the outside of a movable pulley (36) and the inside of fixed pulleys (23, 24), the two ends of the SMA cable (4) are respectively wrapped around two pulley grooves of the double-layer fixed pulley (24), the two ends of the SMA cable (4) are fixedly connected with bolts (42), the bolts (42) pass through the reserved bolt holes of the anchor plate (25), and the SMA cable (4) is tightened by the nut (41).

[0005] In a preferred embodiment, the upper movable block (1) is located at a central position above the lower connecting plate (2) and its sides are parallel. The limit block (22) is fixedly mounted at the middle position of the front, back, left and right sides of the four sides of the lower connecting plate (2). The limit block (22) is divided into two parts, and a certain space is reserved in the middle to allow the first connecting rod (32) to pass through. The sliding bearing (21) is fixedly mounted on the outer side of the middle position of the two limit blocks (22) so that the first connecting rod (32) can pass through the sliding bearing (21). The fixed pulley (23) and the double-layer fixed pulley (24) are fixedly mounted at the four corner positions of the lower connecting plate (2) through a central roller. The double-layer fixed pulley (24) provides a guiding function for the two ends of the SMA cable (4). The anchor plate (25) is fixedly mounted on the outer side of the double-layer fixed pulley (24) for anchoring the SMA cable (4).

[0006] In a preferred embodiment, the inner side of the first connecting rod (32) is connected to the push plate (31). During assembly, the outer side passes through the sliding bearing (21), and the first connecting rod (32) and the second connecting rod (34) are connected by a sleeve bolt stopper (33). When the connecting rod system is assembled, the push plate (31) is close to the upper movable block (1), and the distance between the push plate (31) and the limit stopper (22) is the maximum design displacement d in the direction of movement. max The range of motion of the upper movable block (1) in each direction is the maximum design displacement. There are push plates (31) on the front, back, left and right sides of the upper movable block (1). The push plates (31) can limit the range of motion of the upper movable block (1). After assembly, the sleeve bolt stopper (33) is in close contact with the sliding bearing (21), so that the movable pulley (36) will not move inward under the pulling force of the SMA cable (4).

[0007] In a preferred embodiment, the upper movable block (1) is connected to the main beam at the top and has a rectangular cross-sectional shape; the upper movable block (1) is located at the center of the lower connecting plate (2), and the push plate (31) of the first connecting rod (32) of the connecting rod system is equivalent to contacting the four sides of the upper movable block (1). The upper movable block (1) is not placed on the lower connecting plate (2). When the main beam and the pier undergo relative displacement, the upper movable block (1) and the lower connecting plate (2) undergo relative movement.

[0008] In a preferred embodiment, the SMA cable system is assembled after the upper movable block, the connecting rod system and the lower connecting plate system are assembled, and the SMA cable (4) is arranged in a ring shape, and the SMA cable (4) is wrapped around the outer side of the movable pulley (36) on the connecting rod system.

[0009] In a preferred embodiment, the SMA cable (4) is wrapped around the inner side of the fixed pulleys (23, 24) fixedly mounted on the lower connecting plate (2).

[0010] In a preferred embodiment, the SMA cable (4) is wrapped around the outer side of the fixed pulleys (23, 24) fixedly mounted on the lower connecting plate (2).

[0011] In a preferred embodiment, the movable pulley (36) and the fixed pulleys (23, 24) are both provided with pulley grooves, and the double-layer fixed pulley (24) is provided with two upper and lower pulley grooves, and the pulley grooves facilitate the installation of the SMA cable (4); the two ends of the SMA cable (4) are respectively surrounded by the two pulley grooves of the double-layer fixed pulley (24), and the two ends of the SMA cable (4) are fixedly connected with bolts (42), and the bolts (42) pass through the reserved bolt holes of the anchor plate (25), and the SMA cable (4) is tightened by the nut (41).

[0012] The present invention also provides a method for calculating the restoring force of a planar multi-directional bridge shock-absorbing and energy-dissipating device with a self-resetting function, and calculates the relationship between the elongation of the SMA cable and the displacement of the shock-absorbing device; the leftmost point of the fixed pulley is point A, and the rightmost point of the movable pulley is point B. At this time, AB is in a vertical state. If the vertical distance between the two fixed pulleys is L, the length of the SMA cable between AB is L AB (0) = L / 2, the vertical height of AB is H AB =L / 2;

[0013] When the movable pulley moves to the right by a displacement of d, the horizontal width W of AB AB = d, the tangent point between the SMA cable and the fixed pulley is point C, and the tangent point between the SMA cable and the movable pulley is point D; assuming that the inclination angle of BC is α, then the arc length of arc AC is α, and the arc length L AC =αR1, vertical height H AC =R1sinα, horizontal length W AC =R1-R1cosα; Similarly, the arc DB has an angle of α and an arc length of L DB =αR1, vertical height H DB =R2sinα, horizontal length W DB =R2-R2cosα; vertical height of CD H CD =H AB -H AC -H DB , length L CD =H CD / cosα, horizontal width W CD =H CD × tanα, the horizontal length W of AB AB =W AC +W CD +W DB , and because W AB =d, the following equation holds true:

[0014] R1-R1cosα+(L / 2-R1sinα-R2sinα)tanα+R2-R2cosα=d (1)

[0015] Solve α by formula (1); Formula (1) is highly nonlinear, and it is difficult to solve α by algebraic method. A numerical solution method is used to obtain a high-precision calculation result;

[0016] The length of the SMA cable between AB is L AB (d) = L AC +L CD +L DB ; According to the symmetry between the two sides, the cable extension ΔL(d) when the movable pulley moves to the right by a distance d = 2[L AB (d)-L AB (0)], that is:

[0017] ΔL(d)=2[αR1+(L / 2-R1sinα-R2sinα) / cosα+αR2-L / 2] (2)

[0018] During assembly, a certain initial displacement d0 is preset for the movable pulley, so that the SMA cable has a certain inclination angle α, which can provide a large restoring force even at a small displacement; L a is the length of the SMA cable used for anchoring at both ends, which is twice the length of the SMA cable from the anchor position to the tangent position with the double-layer fixed pulley plus half the circumference of the double-layer fixed pulley; for the annular SMA cable, if the initial displacements in the four directions of front, back, left, and right are all set to d0, its initial circumference is:

[0019] P=4L-2πR1+4ΔL(d0) (3)

[0020] If the upper movable block moves rightward by displacement d s , when the initial gap between the upper movable block and the connecting rod is not considered, the displacement d of the movable pulley relative to the reference state s +d0, that is, the movable pulley moves d after the preset displacement d0 s ; SMA cable elongation δ(d s )=ΔL(d s +d0)-ΔL(d0), SMA cable strain:

[0021] ε=δ(d s ) / P (4)

[0022] If the relationship between the SMA cable tension T and the strain ε is T(ε), then the restoring force of the shock absorber is:

[0023] F=2T(ε)sinα (5)

[0024] Formula (4) establishes the relationship between the SMA cable strain ε and the structural relative displacement d s The relationship between the SMA cable strain ε and the restoring force F is established by formula (5). Combining formula (4) and formula (5), the relationship between the restoring force F and the relative displacement d of the structure is obtained. s relationship.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1) Bidirectional self-reset. Compared with traditional cables, the self-reset capability is enhanced.

[0027] 2) It has multi-directional limiting capabilities to avoid excessive displacement that may cause support voids and beam drop.

[0028] 3) The annular cable is used to reduce the size of the device, avoiding the problems of long SMA cable length, large size of shock-absorbing and energy-absorbing device, and difficulty in transportation and installation caused by large deformation requirements. The device size can be effectively reduced to meet the needs of large structural deformation.

[0029] 4) Realize the planar multi-directional shock absorption effect, improve the utilization rate of SMA cables, and save costs.

[0030] 5) The SMA cable is easy to replace. After experiencing multiple vibrations, the SMA cable can be replaced to restore the shock absorber to its optimal working state. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of calculation of the planar multi-directional shock absorbing device in the embodiment of the present invention, wherein (a) is the reference state, and (b) is the displacement d of the movable pulley moving to the right;

[0032] Figure 2 The SMA cable used in the embodiment of the present invention is compared with the traditional unidirectional shock absorbing device in a single direction and in multiple directions;

[0033] Figure 3 This is a schematic diagram of the structure of the device in an embodiment of the present invention;

[0034] Figure 4 It is a structural schematic diagram of an upper movable block in an embodiment of the present invention;

[0035] Figure 5 It is a structural schematic diagram of the lower connecting plate system in an embodiment of the present invention;

[0036] Figure 6 It is a structural schematic diagram of a connecting rod system in an embodiment of the present invention;

[0037] Figure 7 Schematic diagram of the structure of the SMA cable system in an embodiment of the present invention;

[0038] Figure 8 is a schematic diagram of the device in an initial state according to an embodiment of the present invention;

[0039] Fig. 9 This is a working state diagram of the upper movable block in the embodiment of the present invention moving 10 cm to the right relative to the lower connecting plate;

[0040] Fig.10 This is a working state diagram of the upper movable block in the embodiment of the present invention moving 30 cm to the right relative to the lower connecting plate;

[0041] Fig.11 This is a working state diagram of the upper movable block in the embodiment of the present invention moving 10 cm to the right and upward relative to the lower connecting plate;

[0042] Fig.12 This is a working state diagram of the upper movable block in the embodiment of the present invention moving 20 cm to the right and upward relative to the lower connecting plate;

[0043] In the figure: 1, upper movable block; 2, lower connecting plate; 21, sliding bearing; 22, limit stopper; 23, fixed pulley; 24, double-layer fixed pulley; 25, anchor plate; 31, baffle; 32, first connecting rod; 33, sleeve bolt stopper; 34, second connecting rod; 35, connecting piece; 36, movable pulley; 4, SMA cable; 41, nut; 42, bolt. DETAILED DESCRIPTION

[0044] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0045] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0046] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application; as used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or their combinations.

[0047] like Figure 1-12As shown, this embodiment provides a planar multi-directional bridge shock absorption and energy dissipation device with a self-resetting function, including an upper movable block 1, a lower connecting plate system, a connecting rod system and an SMA cable system; the upper movable block 1 is connected to the main beam at the top and has a rectangular cross-sectional shape; the lower connecting plate system includes a lower connecting plate 2, a sliding bearing 21, a limit stopper 22, a fixed pulley 23, a double-layer fixed pulley 24 and an anchor plate 25; the lower connecting plate 2 has a rectangular cross-sectional shape and is connected to the bridge pier at the bottom; the sliding bearing 21 and the limit stopper 22 are fixedly arranged in the front, rear, left and right directions above the lower connecting plate 2, wherein the limit stopper 22 is arranged on the inner side of the sliding bearing 21; the fixed pulley 23 and the double-layer fixed pulley 24 are fixedly arranged near four corner points above the lower connecting plate 2, wherein the fixed pulleys 23 are arranged at three corner points and the double-layer fixed pulley 24 is arranged at one corner point; the anchor plate 25 is fixedly arranged on the double-layer fixed pulley 24 on the lower connecting plate 2 The outer side of the arrangement position; the connecting rod system includes a push plate 31, a first connecting rod 32, a sleeve bolt block 33, a second connecting rod 34, a connecting piece 35 and a movable pulley 36; the first connecting rod 32 and the push plate 31 are fixed to each other, the first connecting rod 32 and the second connecting rod 34 are connected by the sleeve bolt block 33, the second connecting rod 34 and the connecting piece 35 are fixed to each other, the movable pulley 36 has a central roller, and the connecting piece 35 and the central roller are fixed to each other; the SMA cable system includes an SMA cable 4, a nut 41 and a bolt 42; the SMA cable 4 is arranged in a ring shape, the SMA cable 4 is wrapped around the outer side of the movable pulley 36 and around the inner side of the fixed pulleys 23 and 24, the two ends of the SMA cable 4 are respectively wrapped around the two pulley grooves of the double-layer fixed pulley 24, the two ends of the SMA cable 4 are fixed with connecting bolts 42, the bolts 42 pass through the reserved bolt holes of the anchor plate 25, and the SMA cable 4 is tightened by the nut 41.

[0048] like Figure 5 As shown, in this embodiment, the upper movable block 1 in the device is located in the center above the lower connecting plate 2 and the sides are parallel. The limit block 22 in the system is fixedly installed in the middle position of the front, back, left and right sides of the four sides of the lower connecting plate 2. The limit block 22 is divided into two pieces, and a certain space is reserved in the middle for the first connecting rod 32 to pass through; the sliding bearing 21 in the system is fixedly installed on the outside of the middle position of the two limit blocks 22, so that the first connecting rod 32 can pass through the sliding bearing 21; the fixed pulley 23 and the double-layer fixed pulley 24 in the system are fixedly installed at the four corner positions of the lower connecting plate 2 through the central roller, and the double-layer fixed pulley 24 provides a guiding effect for the two ends of the SMA cable 4, and the anchor plate 25 is fixedly installed on the outer side of the double-layer fixed pulley 24 for anchoring the SMA cable 4.

[0049] like Figure 6As shown, in this embodiment, the inner side of the first connecting rod 32 in the device is connected to the push plate 31. When assembled, the outer side passes through the sliding bearing 21, and the first connecting rod 32 and the second connecting rod 34 are connected by the sleeve bolt block 33; when the connecting rod system is assembled, the push plate 31 is close to the upper movable block 1, and the distance between the push plate 31 and the limit block 22 is the maximum design displacement d in the direction of movement. max , the range of motion of the upper movable block 1 in each direction is the maximum design displacement, and there are push plates 31 on the front, back, left and right sides of the upper movable block 1. The push plates 31 can limit the range of motion of the upper movable block 1. Therefore, it is appropriate to design the side length of the upper movable block 1 and the length of the push plate 31 to be equal, and its design length is slightly larger than the maximum design displacement in the direction parallel to the side length; for example, when the upper movable block 1 pushes the push plate 31 to move to the left and reaches the maximum design displacement in this direction, the upper movable block 1 should be able to continue to push the front or rear push plate 31 to move, and should not be out of contact with the front and rear push plates 31, so as to achieve two-way energy consumption and self-resetting capabilities; in addition, the length of the upper movable block 1 on the front and rear sides and its length on the left and right sides can be designed to be unequal in length, so as to achieve different horizontal two-way displacement capabilities; after assembly, the sleeve bolt stopper 33 is close to the sliding bearing 21, so that the movable pulley 36 will not move inward under the tension of the SMA cable 4.

[0050] like Figure 4 As shown, in this embodiment, the upper movable block 1 in this device is connected to the main beam above, and the cross-sectional shape is rectangular; the upper movable block 1 is located at the center of the lower connecting plate 2, and the push plate 31 of the first connecting rod 32 of the connecting rod system is equivalent to contacting the four sides of the upper movable block 1, and the upper movable block 1 is not placed on the lower connecting plate 2, and there is a certain distance between the two. When the main beam and the pier undergo relative displacement, the upper movable block and the lower connecting plate will undergo relative movement.

[0051] like Figure 7As shown, in this embodiment, the SMA cable system in the device is assembled after the upper movable block, the connecting rod system and the lower connecting plate system are assembled. The SMA cable 4 in the cable system is arranged in a ring shape, and the SMA cable 4 is wrapped around the outer side of the movable pulley 36 on the connecting rod system. A preferred solution is that the SMA cable 4 is wrapped around the inner side of the fixed pulleys 23 and 24 fixedly installed on the lower connecting plate 2. An optional solution is that the SMA cable 4 is wrapped around the outer side of the fixed pulleys 23 and 24 fixedly installed on the lower connecting plate 2; and the movable pulley 36 and the fixed pulleys 23 and 24 are all provided with pulley grooves, and the double-layer fixed pulley 24 is provided with two upper and lower pulley grooves The pulley groove facilitates the installation of the SMA cable 4 and prevents the SMA cable 4 from falling off; finally, the two ends of the SMA cable 4 are respectively surrounded by the two pulley grooves of the double-layer fixed pulley 24 to prevent the SMA cable 4 from crossing and overlapping, thereby realizing the normal telescopic function of the SMA. The two ends of the SMA cable 4 are fixedly connected with bolts 42, and the bolts 42 pass through the reserved bolt holes of the anchor plate 25, and the SMA cable 4 is tightened by the nuts 41, which can prevent the SMA cable 4 from loosening and falling off, and the SMA cable is easy to install. When the performance of the SMA cable is reduced after multiple vibrations, the SMA cable can be replaced to restore the shock absorbing device to the best use state.

[0052] The shock absorption and energy dissipation device and the calculation method of the restoring force are as follows:

[0053] In case of unidirectional displacement, the schematic diagram of restoring force calculation is as follows: Figure 1 As shown, the key lies in calculating the relationship between the elongation of the SMA cable and the displacement of the shock absorbing device. Figure 1 (a) is the reference state for calculation. Point A is the leftmost point of the fixed pulley and point B is the rightmost point of the movable pulley. At this time, AB is in a vertical state. If the vertical distance between the two fixed pulleys is L, then the length of the SMA cable between AB is L AB (0) = L / 2, the vertical height of AB is H AB =L / 2.

[0054] When the movable pulley moves to the right by a displacement of d, Figure 1 As shown in (b), the horizontal width W of AB AB =d, C is the tangent point between the SMA cable and the fixed pulley, and D is the tangent point between the SMA cable and the movable pulley. Assuming the inclination angle of BC is α, the arc length of arc AC is α, and the arc length L is AC =αR1, vertical height H AC =R1sinα, horizontal length W AC =R1-R1cosα; Similarly, the arc DB has an angle of α and an arc length of L DB =αR1, vertical height H DB =R2sinα, horizontal length W DB =R2-R2cosα. The vertical height of CD is H CD =HAB -H AC -H DB , length L CD =H CD / cosα, horizontal width W CD =H CD × tanα, the horizontal length W of AB AB =W AC +W CD +W DB , and because W AB =d, the following equation holds true:

[0055] R1-R1cosα+(L / 2-R1sinα-R2sinα)tanα+R2-R2cosα=d (1)

[0056] α can be solved by formula (1). Formula (1) is highly nonlinear, and it is difficult to solve α by algebraic method. Numerical solution method can be used to obtain high-precision calculation results.

[0057] The length of the SMA cable between AB is L AB (d) = L AC +L CD +L DB . According to the symmetry of both sides, the cable extension ΔL(d) when the movable pulley moves to the right by a distance d is 2[L AB (d)-L AB (0)], that is:

[0058] ΔL(d)=2[αR1+(L / 2-R1sinα-R2sinα) / cosα+αR2-L / 2] (2)

[0059] During assembly, a certain initial displacement d0 is preset for the movable pulley, so that the SMA cable has a certain inclination angle α, which can provide a large restoring force even at a small displacement. a is the length of the SMA cable used for anchoring at both ends, which is twice the length of the SMA cable from the anchor position to the position tangent to the double-layer fixed pulley plus half the circumference of the double-layer fixed pulley. For the annular SMA cable, if the initial displacements in the four directions of front, back, left, and right are all set to d0, its initial circumference is:

[0060] P=4L-2πR1+4ΔL(d0) (3)

[0061] If the upper movable block moves rightward by displacement d s , when the initial gap between the upper movable block and the connecting rod is not considered, the displacement d of the movable pulley relative to the reference state s +d0, that is, the movable pulley moves d after the preset displacement d0 s. SMA cable elongation δ(d s )=ΔL(d s +d0)-ΔL(d0), SMA cable strain:

[0062] ε=δ(d s ) / P (4)

[0063] If the relationship between the SMA cable tension T and the strain ε is T(ε), then the restoring force of the shock absorber is:

[0064] F=2T(ε)sinα (5)

[0065] Formula (4) establishes the relationship between the SMA cable strain ε and the relative displacement d s Formula (5) establishes the relationship between the SMA cable strain ε and the restoring force F. Combining formula (4) and formula (5), we can get the relationship between the restoring force F and the relative displacement d of the structure. s relationship.

[0066] The SMA cable strain ε is converted into the relative displacement d of the structure through the test data. s It can be preliminarily inferred that the restoring force F of the shock absorber and the displacement d s Taking L = 0.7m, R1 = R2 = 0.05m, d0 = 0.4m as an example, the relationship between the restoring force and displacement of the device in one direction is as follows: Figure 2 As shown. Figure 2 In the figure, the blue solid line represents the restoring force relationship of the plane multi-directional shock absorbing device designed by the present invention, and the orange dotted line represents the restoring force relationship of the traditional unidirectional shock absorbing device under the same amount of SMA material. It can be seen that the mechanical relationship of the two systems is similar, but the shock absorbing device designed by the present invention has multi-directional self-resetting shock absorbing ability, which improves the utilization efficiency of SMA materials. At the same time, although the SMA cable has superelasticity, its strain capacity is not infinite. Taking 10% strain as the design strain of the SMA cable, to achieve a displacement capacity of 30cm, the SMA cable length of 30cm / 10%=3.0m is required. In the traditional SMA shock absorbing device, the device size must be greater than or equal to 3.0m, while the shock absorbing device designed by the present invention can miniaturize the size of the shock absorbing device by arranging the SMA cable in a ring.

[0067] In case of bidirectional displacement, the calculation method of the shock absorbing device is the same as that of unidirectional displacement, and the elongation of the cable in two directions is considered.

[0068] Situation 1: The upper movable block 1 moves rightward relative to the lower connecting plate 2.

[0069] When an earthquake occurs, the upper movable block 1 moves to the right relative to the lower connecting plate 2. For example, if the upper movable block 1 moves 10 cm to the right, Fig. 9As shown, the upper movable block 1 pushes the right push plate 31 to drive the connecting rod to move 10 cm to the right, while the connecting rods in other directions will not move due to the blocking effect of the sleeve bolt block 33. The SMA cable 4 is stretched, generating a leftward reset capability for the lower connecting plate 2. When the earthquake effect ends, it returns to the initial position, realizing the self-reset function.

[0070] Take the above limit displacement of movable block 1 to the right by 30cm as an example. Fig.10 As shown, the upper movable block 1 pushes the right push plate 31 to drive the connecting rod to move 30 cm to the right, while the connecting rods in other directions will not move due to the blocking effect of the sleeve bolt block 33, but the push plate 31 will collide with the limit block 22 fixed to the lower connecting plate 2 to prevent its displacement from further expanding, thereby achieving a limiting effect and preventing the bearing from being emptied and the beam from falling due to excessive displacement, thereby realizing the limiting function.

[0071] Situation 2: The upper movable block 1 moves rightward and upward relative to the lower connecting plate 2.

[0072] When an earthquake occurs, the upper movable block 1 moves rightward and upward relative to the lower connecting plate 2. For example, if the upper movable block 1 moves rightward and upward by 10 cm, Fig.11 As shown, the upper movable block 1 simultaneously pushes the right and upper push plates 31 to drive the connecting rod to move 10 cm to the right and upward, while the connecting rods in other directions will not move due to the blocking effect of the sleeve bolt block 33. The SMA cable 4 is stretched, generating a leftward and downward reset capability for the lower connecting plate 2. When the earthquake effect ends, it returns to the initial position, realizing a bidirectional self-reset function.

[0073] Take the displacement of the movable block 1 to the right and upward by 20 cm as an example. Fig.12 As shown, the upper movable block 1 pushes the right and upper push plates 31 to drive the connecting rod to move 20 cm to the right and upward, while the connecting rods in other directions will not move due to the blocking effect of the sleeve bolt block 33. The SMA cable 4 is stretched, generating a reset capability to the left and downward for the lower connecting plate 2. When the earthquake effect ends, it returns to the initial position, realizing a bidirectional self-reset function.

[0074] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and its core ideas of this application. The above is only the preferred implementation method of this application. It should be pointed out that due to the limitations of textual expression and the objective existence of infinite specific structures, ordinary technicians in this technical field can make several improvements, modifications or changes without departing from the principles of this application, and can also combine the above technical features in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the concept and technical solution of the invention to other occasions without improvement, should be regarded as the scope of protection of this application.

Claims

1. A planar multi-directional bridge shock absorption and energy dissipation device with self-reset function, characterized in that: The invention comprises an upper movable block (1), a lower connecting plate system, a connecting rod system and an SMA cable system; the upper movable block (1) is connected to a main beam at the top and has a rectangular cross-sectional shape; the lower connecting plate system comprises a lower connecting plate (2), a sliding bearing (21), a limit stopper (22), a fixed pulley (23), a double-layer fixed pulley (24) and an anchor plate (25); the lower connecting plate (2) has a rectangular cross-sectional shape and is connected to a bridge pier at the bottom; the sliding bearing (21) and the limit stopper (22) are fixedly arranged on the lower connecting plate ( 2) in the four directions of front, rear, left and right above, wherein the limit stopper (22) is arranged on the inner side of the sliding bearing (21); the fixed pulley (23) and the double-layer fixed pulley (24) are fixedly arranged above the lower connecting plate (2) near four corner points, wherein the fixed pulley (23) is arranged at three corner points and the double-layer fixed pulley (24) is arranged at one corner point; the anchor plate (25) is fixedly arranged on the outer side of the double-layer fixed pulley (24) arrangement position on the lower connecting plate (2); the connecting rod system includes a push plate (31), a first a connecting rod (32), a sleeve bolt block (33), a second connecting rod (34), a connecting piece (35) and a movable pulley (36); the first connecting rod (32) and the push plate (31) are fixed to each other, the first connecting rod (32) and the second connecting rod (34) are connected by the sleeve bolt block (33), the second connecting rod (34) and the connecting piece (35) are fixed to each other, the movable pulley (36) has a central roller, and the connecting piece (35) and the central roller are fixed to each other; the SMA cable system includes an SMA cable The SMA cable (4), a nut (41) and a bolt (42); the SMA cable (4) is arranged in a ring shape, the SMA cable (4) is wrapped around the outside of the movable pulley (36) and the inside of the fixed pulleys (23, 24), the two ends of the SMA cable (4) are respectively wrapped around the two pulley grooves of the double-layer fixed pulley (24), the two ends of the SMA cable (4) are fixedly connected with bolts (42), the bolts (42) pass through the reserved bolt holes of the anchor plate (25), and the SMA cable (4) is tightened by the nut (41).

2. A planar multi-directional bridge shock absorption and energy dissipation device with self-resetting function according to claim 1, characterized in that: The upper movable block (1) is located at a central position above the lower connecting plate (2) and has parallel sides. The limit block (22) is fixedly mounted at the middle position of the front, back, left and right sides of the four sides of the lower connecting plate (2). The limit block (22) is divided into two parts, and a certain space is reserved in the middle to allow the first connecting rod (32) to pass through. The sliding bearing (21) is fixedly mounted on the outer side of the middle position of the two limit blocks (22), so that the first connecting rod (32) can pass through the sliding bearing (21). The fixed pulley (23) and the double-layer fixed pulley (24) are fixedly mounted at the four corner positions of the lower connecting plate (2) through a central roller. The double-layer fixed pulley (24) provides a guiding function for the two ends of the SMA cable (4). The anchor plate (25) is fixedly mounted on the outer side of the double-layer fixed pulley (24) to anchor the SMA cable (4).

3. The planar multi-directional bridge shock absorption and energy dissipation device with self-resetting function according to claim 1 is characterized in that: The inner side of the first connecting rod (32) is connected to the push plate (31). During assembly, the outer side passes through the sliding bearing (21), and the first connecting rod (32) and the second connecting rod (34) are connected by a sleeve bolt stopper (33). When the connecting rod system is assembled, the push plate (31) is close to the upper movable block (1), and the distance between the push plate (31) and the limit stopper (22) is the maximum design displacement d in the direction of movement. max The range of motion of the upper movable block (1) in each direction is the maximum design displacement. There are push plates (31) on the front, back, left and right sides of the upper movable block (1). The push plates (31) can limit the range of motion of the upper movable block (1). After assembly, the sleeve bolt stopper (33) is in close contact with the sliding bearing (21), so that the movable pulley (36) will not move inward under the pulling force of the SMA cable (4).

4. The planar multi-directional bridge shock absorption and energy dissipation device with self-resetting function according to claim 1 is characterized in that: The upper movable block (1) is connected to the main beam at the top and has a rectangular cross-sectional shape; the upper movable block (1) is located at the center of the lower connecting plate (2); the push plate (31) of the first connecting rod (32) of the connecting rod system is equivalent to contacting the four sides of the upper movable block (1); the upper movable block (1) is not placed on the lower connecting plate (2); when the main beam and the pier undergo relative displacement, the upper movable block (1) and the lower connecting plate (2) undergo relative movement.

5. The planar multi-directional bridge shock absorption and energy dissipation device with self-resetting function according to claim 1 is characterized in that: The SMA cable system is assembled after the upper movable block, the connecting rod system and the lower connecting plate system are assembled. The SMA cable (4) is arranged in a ring shape and surrounds the outer side of the movable pulley (36) on the connecting rod system.

6. A planar multi-directional bridge shock absorption and energy dissipation device with self-resetting function according to claim 5, characterized in that: The SMA cable (4) is wrapped around the inner side of the fixed pulleys (23, 24) fixedly mounted on the lower connecting plate (2).

7. The planar multi-directional bridge shock absorption and energy dissipation device with self-resetting function according to claim 5 is characterized in that: The SMA cable (4) is wrapped around the outer side of the fixed pulleys (23, 24) fixedly mounted on the lower connecting plate (2).

8. A planar multi-directional bridge shock absorption and energy dissipation device with self-resetting function according to claim 6 or 7, characterized in that: The movable pulley (36) and the fixed pulleys (23, 24) are both provided with pulley grooves, and the double-layer fixed pulley (24) is provided with two upper and lower pulley grooves, and the pulley grooves facilitate the installation of the SMA cable (4); the two ends of the SMA cable (4) are respectively surrounded by the two pulley grooves of the double-layer fixed pulley (24), and the two ends of the SMA cable (4) are fixedly connected with bolts (42), and the bolts (42) pass through the reserved bolt holes of the anchor plate (25), and the SMA cable (4) is tightened by the nut (41).

9. A method for calculating the restoring force of a planar multi-directional bridge shock-absorbing and energy-dissipating device with a self-resetting function according to any one of claims 1 to 7, characterized in that: Calculate the relationship between the elongation of the SMA cable and the displacement of the shock absorber; the leftmost point of the fixed pulley is point A, and the rightmost point of the movable pulley is point B. At this time, AB is in a vertical state. If the vertical distance between the two fixed pulleys is L, then the length of the SMA cable between AB is L AB (0) = L / 2, the vertical height of AB is H AB =L / 2; When the movable pulley moves to the right by a displacement of d, the horizontal width W of AB AB = d, the tangent point between the SMA cable and the fixed pulley is point C, and the tangent point between the SMA cable and the movable pulley is point D; assuming that the inclination angle of BC is α, then the arc length of arc AC is α, and the arc length L AC =αR1, vertical height H AC =R1sinα, horizontal length W AC =R1-R1cosα; Similarly, the arc DB has an angle of α and an arc length of L DB =αR1, vertical height H DB =R2sinα, horizontal length W DB =R2-R2cosα; vertical height of CD H CD =H AB -H AC -H DB , length L CD =H CD / cosα, horizontal width W CD =H CD × tanα, the horizontal length W of AB AB =W AC +W CD +W DB , and because W AB =d, the following equation holds true: R1-R1 cosα+(L / 2-R1 sinα-R2sinα)tanα+R2-R2cosα=d (1) Solve α by formula (1); Formula (1) is highly nonlinear, and it is difficult to solve α by algebraic method. A numerical solution method is used to obtain a high-precision calculation result; The length of the SMA cable between AB is L AB (d) = L AC +L CD +L DB ; According to the symmetry between the two sides, the cable extension ΔL(d) when the movable pulley moves to the right by a distance d = 2[L AB (d)-L AB (0)], that is: ΔL(d)=2[αR1+(L / 2-R1sinα-R2sinα) / cosα+αR2-L / 2] (2) During assembly, a certain initial displacement d0 is preset for the movable pulley, so that the SMA cable has a certain inclination angle α, which can provide a large restoring force even at a small displacement; L a is the length of the SMA cable used for anchoring at both ends, which is twice the length of the SMA cable from the anchor position to the tangent position with the double-layer fixed pulley plus half the circumference of the double-layer fixed pulley; for the annular SMA cable, if the initial displacements in the four directions of front, back, left, and right are all set to d0, its initial circumference is: P=4L-2πR1+4ΔL(d0) (3) If the upper movable block moves rightward by displacement d s , when the initial gap between the upper movable block and the connecting rod is not considered, the displacement d of the movable pulley relative to the reference state s +d0, that is, the movable pulley moves d after the preset displacement d0 s ; SMA cable elongation δ(d s )=ΔL(d s +d0)-ΔL(d0), SMA cable strain: e=δ(d s ) / P (4) If the relationship between the SMA cable tension T and the strain ε is T(ε), then the restoring force of the shock absorber is: F=2T(ε)sinα (5) Formula (4) establishes the relationship between the SMA cable strain ε and the structural relative displacement d s The relationship between the SMA cable strain ε and the restoring force F is established by formula (5). Combining formula (4) and formula (5), the relationship between the restoring force F and the relative displacement d of the structure is obtained. s relationship.

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