A planar multi-directional bridge shock absorption and energy dissipation device with self-resetting function and a restoring force calculation method thereof

Abstract

This invention proposes a planar multi-directional bridge shock absorption and energy dissipation device with a self-resetting function and a method for calculating its restoring force. The device comprises an upper movable block, a lower connecting plate system, a connecting rod system, and an SMA cable system. The lower connecting plate system consists of a lower connecting plate, a sliding bearing, a limit stop, a fixed pulley, a double-layer fixed pulley, and an anchor plate. The connecting rod system consists of a push plate, a first connecting rod, a sleeve bolt stop, a second connecting rod, a connector, and a movable pulley. The SMA cable system consists of an SMA cable, bolts, and nuts. The SMA cable wraps around the inside and outside of the fixed and movable pulleys, respectively, and is anchored to the anchor plate at both ends by bolts. The upper movable block can push the corresponding push plate in any direction on the plane. The SMA cable is stretched to achieve shock absorption and energy dissipation, as well as self-resetting functions. The limit stop achieves a limiting function by restricting the range of motion of the push plate. By analyzing the geometric relationship between the upper movable block's movement distance and the elongation of the SMA cable, a method for calculating the device's restoring force is derived. The present invention can reduce the size of the device, provide bidirectional self-resetting and limiting functions, and improve the use efficiency of the SMA cable.

Description

Technical Field

[0001] The present 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 in bridge structural design. Especially in near-fault areas, bridges are subject to large seismic displacement requirements under velocity pulse earthquakes. The main beams and piers are prone to large relative displacements, and the relative displacements are not limited to a specific direction. Therefore, shock-absorbing and energy-dissipating devices must not only have good energy dissipation capabilities, but also multi-directional large displacement capabilities. Shape memory alloys (SMAs) have excellent energy dissipation and deformation capabilities due to their superelastic properties. Generally, the ultimate strain of SMA cables can reach 5% to 10%. Despite this, to achieve large displacement capabilities, longer SMA cables are 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 result in the size of the shock-absorbing and energy-dissipating device being too large. Summary of the Invention

[0003] In view of this, the purpose 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 smaller structural size and has bidirectional self-resetting and limiting functions.

[0004] To achieve the above-mentioned purpose, the present invention adopts the following technical solution: a plane 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 portion of the upper movable block (1) is connected to the main beam, and the cross-sectional shape is rectangular; 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) is rectangular in cross-sectional shape, and is connected to the main beam at the bottom. The bridge pier; the sliding bearing (21) and the limit block (22) are fixedly arranged on the front, rear, left and right directions above the lower connecting plate (2), wherein the limit block (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 on the lower connecting plate (2) near the four corner points, 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 lower connecting plate (2) near the position where the double-layer fixed pulley (24) is arranged. 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 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 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).

[0005] In a preferred embodiment, the upper movable block (1) is located in the center above the lower connecting plate (2) and the sides are parallel, the limit block (22) 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 to allow the first connecting rod (32) to pass through; the sliding bearing (21) 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) are fixedly installed at the four corner positions of the lower connecting plate (2) through the central roller, the double-layer fixed pulley (24) provides a guiding function 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).

[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 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. 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 tension of the SMA cable (4).

[0007] In a preferred embodiment, the upper movable block (1) is connected to the main beam above 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) will 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 fixed 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 plane multi-directional bridge shock-absorbing and energy-dissipating device with a self-resetting function, which 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, 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;

[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 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:

[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. The numerical solution method is used to obtain high-precision calculation results;

[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 is 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. It 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 displacement in the four directions of front, back, left, and right is all set to d0, its initial circumference is:

[0019] P=4L-2πR1+4ΔL(d0) (3)

[0020] If the upper movable block moves to the right 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 will move 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 relative displacement d s The relationship between the SMA cable strain ε and the restoring force F is established by formula (5). Combining formulas (4) and (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 loss 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-dissipating device, and difficulty in transportation and installation caused by the need to achieve large deformation. It can effectively reduce the size of the device and adapt to the needs of large structural deformation.

[0029] 4) Realize the multi-directional shock absorption effect on the plane, 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 condition. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of calculation of the planar multi-directional vibration damping device in an embodiment of the present invention, where (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 used in a single direction for multi-directional shock absorption compared with a traditional unidirectional shock absorption device;

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

[0034] Figure 4 Schematic diagram of the structure of the upper movable block in an embodiment of the present invention;

[0035] Figure 5 Schematic diagram of the structure of the lower connecting plate system in an embodiment of the present invention;

[0036] Figure 6 Schematic diagram of the structure of the 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] Figure 9 This is a working state diagram of the embodiment of the present invention in which the upper movable block moves 10 cm to the right relative to the lower connecting plate;

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

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

[0042] Figure 12 This is a working state diagram of the upper movable block in the embodiment of the present invention, which moves 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 stop; 23. Fixed pulley; 24. Double-layer fixed pulley; 25. Anchor plate; 31. Baffle; 32. First connecting rod; 33. Sleeve bolt stop; 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 with reference to the accompanying drawings and embodiments.

[0045] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as 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, and 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 stop 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 stop 22 are fixedly arranged in the front, rear, left and right directions above the lower connecting plate 2, wherein the limit stop 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 the 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 outside of the arrangement position; the connecting rod system includes a push plate 31, a first connecting rod 32, a sleeve bolt stopper 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, the first connecting rod 32 and the second connecting rod 34 are connected by the sleeve bolt stopper 33, the second connecting rod 34 and the connecting piece 35 are fixed, the movable pulley 36 has a central roller, and the connecting piece 35 and the central roller are fixed; 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 outside of the movable pulley 36 and around the inside of the fixed pulleys 23 and 24, and the two ends of the SMA cable 4 are respectively wrapped around the two pulley grooves of the double-layer fixed pulley 24, and 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 this device 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 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 movable range 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 movable range of the upper movable block 1. Therefore, the side length of the upper movable block 1 and the length of the push plate 31 are designed to be equal, and the 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 the displacement reaches the maximum design displacement in that direction, the upper movable block 1 should also 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 realize two-way energy consumption and self-resetting ability; in addition, the length of the upper movable block 1 on the front and rear sides and the length on the left and right sides can be designed to be unequal, so as to realize 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 its 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 this 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. 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 both provided with pulley grooves, and the double-layer fixed pulley 24 has 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 wrapped around 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 fixed with bolts 42, and the bolts 42 pass through the reserved bolt holes of the anchor plate 25 and tighten the SMA cable 4 through the nuts 41. This 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 deteriorates after multiple vibrations, the SMA cable can be replaced to restore the shock absorber to its optimal use state.

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

[0053] In case of unidirectional displacement, the restoring force calculation diagram is as follows: Figure 1 As shown in Figure 2, the key lies in calculating the relationship between the elongation of the SMA cable and the displacement of the shock absorber. 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, then 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 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:

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

[0056] Formula (1) can be used to solve α. Formula (1) is highly nonlinear, and it is difficult to solve α by algebraic methods. Numerical solutions 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 between the two 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 The length of the SMA cable used for anchoring at both ends 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 a circular SMA cable, if the initial displacement in the four directions of front, back, left, and right is 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 will move 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] Equation (4) establishes the relationship between the SMA cable strain ε and the relative displacement d s The relationship between the strain ε of the SMA cable and the restoring force F is established by formula (5). Combining formulas (4) and (5), the relationship between the restoring force F and the relative displacement d of the structure can be obtained. 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 solid blue line represents the restoring force relationship of the planar multi-directional shock absorber designed with the present invention, while the dashed orange line represents the restoring force relationship of a conventional unidirectional shock absorber using the same SMA material dosage. While the mechanical relationships of the two systems are similar, the shock absorber designed with the present invention possesses multi-directional, self-resetting shock absorption capabilities, improving the utilization efficiency of the SMA material. Furthermore, although the SMA cable possesses superelasticity, its strain capacity is not infinite. Using a 10% strain as the design strain for the SMA cable, achieving a displacement capacity of 30 cm requires an SMA cable length of 30 cm / 10% = 3.0 m. Conventional SMA shock absorbers require a device size of at least 3.0 m. However, the shock absorber designed with the present invention utilizes a circular arrangement of the SMA cables, enabling a smaller size.

[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 both directions is taken into account.

[0068] Case 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, Figure 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 action 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. Figure 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, preventing its displacement from further expanding, playing a limiting effect, preventing excessive displacement from causing the support to become empty and the beam to fall, thereby realizing the limiting function.

[0071] Scenario 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, Figure 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 reset ability for the lower connecting plate 2 to the left and downward. When the earthquake action ends, it returns to the initial position, realizing a two-way self-reset function.

[0073] Take the above movable block 1 displacement of 20cm to the right and upward as an example. Figure 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 ability for the lower connecting plate 2 to the left and downward. When the earthquake action ends, it returns to the initial position, realizing a two-way 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 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, there are objectively infinite specific structures. For ordinary technicians in this technical field, without departing from the principles of this application, they can also make several improvements, modifications or changes, and can also combine the above technical features in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the inventive concept and technical solution 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 a self-resetting 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 connecting rod system is provided with four, which are respectively provided in the front, back, left and right directions of the upper movable block (1); the upper portion of the upper movable block (1) is connected to the main beam, and the cross-section shape is rectangular; 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) is rectangular in cross-section, and the lower portion is connected to the bridge pier; the The sliding bearing (21) and the limit block (22) are fixedly arranged above the lower connecting plate (2) in the front, rear, left and right directions, wherein the limit block (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 the 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 outside the position where the double-layer fixed pulley (24) is arranged on the lower connecting plate (2). side; 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 member (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 member (35) are fixed to each other, the movable pulley (36) has a central roller, and the connecting member (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 the movable pulley (36) and the inside of the fixed pulley (23), 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); The upper movable block (1) is located in the center above the lower connecting plate (2) and its sides are parallel. The limit block (22) 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 to allow the first connecting rod (32) to pass through. The sliding bearing (21) 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) are fixedly installed at the four corner positions of the lower connecting plate (2) through the 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 installed on the outer side of the double-layer fixed pulley (24) for anchoring the SMA cable (4). The inner side of the first connecting rod (32) 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 a 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. Push plates (31) are present 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 tension of the SMA cable (4). The upper movable block (1) is connected to the main beam above 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 plates (31) of the first connecting rods (32) of the four connecting rod systems respectively contact 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; the second connecting rod (34) extends a certain distance from the lower connecting plate (2).

2. A method for calculating the restoring force of a planar multi-directional bridge shock absorption and energy dissipation device with a self-resetting function according to claim 1, 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 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 = αR2, 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: ( ) By Solve α; It is highly nonlinear, and it is difficult to solve α by algebraic methods. A numerical solution method is used to obtain high-precision calculation results; where R1 represents the radius of the fixed pulley and R2 represents the radius of the movable pulley; 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 is = 2[L AB (d)-L AB (0)], that is: ( ) 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. It 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 displacement in the four directions of front, back, left, and right is all set to d0, its initial circumference is: ( ) If the upper movable block moves to the right 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 will move d after the preset displacement d0 s ; SMA cable elongation δ(d s ) = ΔL(d s +d0)-ΔL(d0), SMA cable strain: ( ) 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: ( ) Mode Establish the relationship between SMA cable strain ε and structural relative displacement d s The relationship, Establish the relationship between the SMA cable strain ε and the restoring force F, the comprehensive formula Japanese style Get the restoring force F and the relative displacement d of the structure s relationship.

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