CN112682470B - Ultralow frequency shock isolation device and design method - Google Patents
Ultralow frequency shock isolation device and design method Download PDFInfo
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Abstract
The invention discloses an ultralow frequency shock isolation device and a design method thereof, wherein the ultralow frequency shock isolation device is arranged between the bottom of a shock isolated object and a foundation, and comprises the following steps: the upper layer shock insulation device, the lower layer shock insulation device and the elastic connecting piece are arranged in sequence; the upper layer shock isolation device and the lower layer shock isolation device are provided with horizontal sliding shock absorption units; the elastic connecting piece is positioned between the sliding damping units; the invention adopts a double-layer shock isolation device structure, obviously reduces the input of earthquake motion energy, and can also realize the reset function.
Description
Technical Field
The invention relates to the field of shock insulation, in particular to an ultralow frequency shock insulation device and a design method thereof.
Background
The seismic isolation technology is a technology which can isolate or weaken seismic energy in order to protect a structure from being damaged by seismic action in the engineering field, mainly adopts a mode of reducing structural frequency to achieve the seismic isolation purpose, but is limited by material performance and safety and stability of a seismic isolation device, and the seismic isolation device which can obviously reduce the structural frequency and can realize a self-resetting function is not available temporarily. This patent aims at providing an ultralow frequency shock isolation device, and the initial shock isolation frequency of device is close to zero, has certain quasi-zero frequency working stroke, can show that the earthquake takes place the time vibrations energy and is transmitted to upper portion by the ground and protected the structure, gets into the nonlinear stiffness region after the quasi-zero frequency stroke, restricts the displacement response of superstructure under the earthquake effect, and can realize that the device size is miniaturized, the cost is cheap, and the shock isolation device can resume initial state after the earthquake ends.
The earthquake causes the damage to the structure, which causes great loss to the life and property safety. For countries with frequent earthquakes.
The destruction of electric power facilities in earthquakes has led to serious economic loss of the nation, and the depth and the range of the destruction have attracted great attention. In earthquakes, the grid power supply equipment is severely damaged, resulting in immeasurable loss of life and property. Earthquake damage investigation finds that electric facilities in the transformer substation have structural characteristics of height, size, weight and the like, and the sleeve pipe structure of most of the electric facilities is made of low-strength and high-brittleness electric porcelain materials, so that the damage phenomenon is serious under the action of an earthquake. The space of the anti-seismic optimization through the power facility structure is small, the additional economic investment is large, and the planning design and the stable development of the power grid are restricted. Aiming at the structural characteristics and weak links of the electric power facilities, relevant anti-seismic measures are necessary to reduce the seismic response of the facilities and protect the safety of the electric power facilities in earthquakes.
The conventional earthquake-resistant technology resists an earthquake by enhancing structural strength, consumes earthquake energy at the cost of damage to the structural member itself, and is poor in economy and safety. The seismic isolation technology is that a seismic isolation device is arranged between a structure and a foundation to form a seismic isolation layer, seismic energy is isolated from being transmitted to an upper structure, the seismic energy input to the upper structure is reduced, meanwhile, the natural vibration period of the upper structure is prolonged, the seismic reaction of the upper structure is reduced, and the expected seismic resistance and shock resistance requirements are met. The seismic isolation technology is applied to building structures, is tested for earthquakes for past decades, is one of the most important achievements of seismic engineering for recent decades, and is an economic, reliable and effective seismic isolation and disaster reduction technology.
The patent names in the prior art are as follows: a rubber lead core vibration isolation support discloses: square rubber sheets and thin steel plates are alternately placed between the two steel plates and are bonded together through vulcanization, four corners are chamfered into round corners, the periphery and protective rubber are vulcanized into a whole, and the lead core is tightly pressed into a preformed hole of the square rubber shock insulation support.
The low rigidity characteristic of rubber is mainly utilized to this patent, through steel sheet restraint rubber deformation direction between the layer, and the isolation bearing is installed at the basis and by between the shock insulation structure, and the level takes place to shear deformation under the seismic action bearing, and the horizontal side rigidity of isolation bearing is little, through reducing superstructure frequency to realize the security of shock insulation function protection architecture under the seismic action. Rubber lead core seismic isolation technology has been widely applied to large building structure seismic design. But has the following disadvantages:
(1) the rubber lead core shock insulation support has the minimum size model, the minimum lateral rigidity of a single support has a limit value, the initial shock insulation frequency is high, the rigidity in stress deformation is not small enough, the shock insulation efficiency is limited, and the rubber lead core shock insulation support is not suitable for a light structure.
(2) The rubber is bonded with the thin steel plate by adopting a vulcanization technology, the requirements on the processing and manufacturing process of the device are high, and the risk of environmental pollution exists in the vulcanization process.
(3) The design of the patent is to reduce earthquake disasters and has no function of preventing mechanical vibration isolation or wind vibration.
Disclosure of Invention
Aiming at the problems that the initial shock insulation frequency value is high, a light structure is not suitable, the shock insulation efficiency is insufficient, the self-resetting after the shock insulation cannot be realized and the like in the prior shock insulation technology, the invention provides the shock insulation technology which has the advantages of small initial shock insulation frequency, wide frequency domain shock insulation effect, high shock insulation efficiency, suitability for various light and heavy structures and self-resetting after the shock insulation.
An ultra-low frequency seismic isolation device is arranged between the bottom of an object to be isolated and a foundation, and comprises: the upper layer shock insulation device, the lower layer shock insulation device and the elastic connecting piece are arranged in sequence; the upper layer shock isolation device and the lower layer shock isolation device are provided with horizontal sliding shock absorption units;
the elastic connection member is located between the sliding damping units.
Preferably, the upper layer seismic isolation apparatus includes: an upper steel frame (21) and a first sliding damping unit, the first sliding damping unit comprising: the upper layer linear guide rail (12), the upper layer sliding block and the upper layer elastic piece;
the upper layer linear guide rail (12) is fixedly connected to the upper layer steel frame (21);
the upper layer sliding block and the elastic connecting piece are arranged on the upper layer linear guide rail (12);
one end of the upper layer elastic piece is connected with the upper layer sliding block, and the other end of the upper layer elastic piece is connected with the inner edge frame of the upper layer steel frame (21);
the upper layer steel frame (21) is connected with a vibration-isolated structure.
Preferably, the upper layer slider and the upper layer elastic member include a plurality of;
the number of the upper layer elastic pieces is twice of that of the upper layer sliding blocks.
Preferably, the lower layer seismic isolation apparatus includes: lower floor steel frame (1) and second slip shock attenuation unit, the second slip shock attenuation unit includes: the lower layer linear guide rail (2), the lower layer slide block and the lower layer elastic piece;
the lower-layer linear guide rail (2) is fixed on the lower-layer steel frame (1);
the lower-layer sliding block and the elastic connecting piece are arranged on the lower-layer linear guide rail (2);
one end of the lower-layer elastic part is connected with the lower-layer sliding block, and the other end of the lower-layer elastic part is connected with the inner edge frame of the lower-layer steel frame (1);
the lower layer steel frame (1) is connected with a foundation.
Preferably, the number of the lower-layer sliding blocks and the number of the lower-layer elastic pieces are multiple;
the number of the lower layer elastic pieces is twice that of the lower layer sliding blocks.
Preferably, the elastic connection member includes: a central slider (3) and an elastic member;
the central sliding block (3) is arranged at the intersection point of the upper layer linear guide rail (12) and the lower layer linear guide rail (2);
the elastic piece comprises a first elastic piece and a second elastic piece;
the first elastic piece is arranged along the direction of the upper layer linear guide rail (12), one end of the first elastic piece is connected with the central sliding block (3), and the other end of the first elastic piece is connected with an inner frame of the upper layer linear guide rail (12);
the second elastic component is followed set up in lower floor's linear guide (2) direction, one end with center slider (3) are connected, the other end with border connection in lower floor's steel frame (1).
Preferably, the first elastic member and the second elastic member each include a spring;
the spring adopts a tension and compression spring with the same specification.
Preferably, the distance between the central slider (3) and the upper layer slider and the distance between the central slider and the lower layer slider are the same.
Preferably, the rubber cushion also comprises a buffer rubber cushion;
the connection part of the upper layer linear guide rail (12) and the inner edge frame of the upper layer steel frame (21) is provided with the buffer rubber pad;
and the joint of the lower linear guide rail (2) and the inner frame of the lower steel frame (1) is provided with a buffer rubber pad.
Preferably, the upper layer elastic member and the lower layer elastic member each include a spring.
Based on the same invention concept, the invention also provides a design method of the ultralow frequency shock isolation device, which comprises the following steps:
sequentially determining an upper layer shock isolation device and a lower layer shock isolation device which are provided with sliding shock absorption units in the horizontal direction;
determining design parameters of a spring between sliding shock absorption units of an upper layer shock insulation device and a lower layer shock insulation device by using a stiffness equation based on the seismic intensity to be met and the displacement range of a shock insulation system installed on the ultralow frequency shock insulation device;
and the stiffness equation is determined by the relationship between the displacement of the vibration-isolated system and the stiffness change curve of the spring.
Preferably, the design parameters of the spring between the sliding shock absorption units of the upper-layer shock insulation device and the lower-layer shock insulation device, which are determined by using a stiffness equation based on the seismic intensity to be satisfied and the displacement range of the shock insulation system installed on the ultra-low frequency shock insulation device, include:
determining the rigidity in a rigidity equation set by using a system motion equation based on the seismic intensity required to be met by the designed ultralow frequency shock isolation device and the displacement range of the shock isolated system in combination with the mass of the shock isolated system;
determining the stiffness and the length of the initial state of the spring and the stiffness and the length of the spring parallel to the motion direction in the system based on the stiffness in the stiffness equation;
wherein the design parameters of the spring include: the initial state of the spring and its length, and the spring rate and length parallel to the direction of motion in the system.
Preferably, the stiffness equation is given by:
wherein l is the original length of the spring, d is the system displacement, and K1For spring rate parallel to the direction of motion in the system, K2The spring rate is perpendicular to the initial state of the motion direction in the system.
Preferably, the system motion equation is as follows:
wherein M is the mass of the object to be isolated; c is system damping; k is the dynamic stiffness of the system;
system acceleration;
the system speed; acc (t): is a seismic exciting force function.
Compared with the prior art, the invention has the beneficial effects that:
1. the invention provides an ultralow frequency shock isolation device which is arranged between the bottom of a shock isolated object and a foundation and comprises: the upper layer shock insulation device, the lower layer shock insulation device and the elastic connecting piece are arranged in sequence; the upper layer shock isolation device and the lower layer shock isolation device are provided with horizontal sliding shock absorption units; the elastic connecting piece is positioned between the sliding damping units; the invention adopts a double-layer shock isolation device structure, obviously reduces the input of earthquake motion energy, and can also realize the reset function.
2. According to the invention, the collision between the sliding block and the inner frame is reduced by adopting the buffer rubber pads at the joint of the upper layer linear guide rail (12) and the inner frame of the upper layer steel frame (21) and the joint of the lower layer linear guide rail (2) and the inner frame of the lower layer steel frame (1).
3. The distance between the central sliding block (3) in the elastic connecting piece and the upper layer sliding block and the lower layer sliding block is the same, because the elastic piece connected with the upper layer sliding block or the lower layer sliding block is vertical to the track, the rigidity and the acting force in the track direction are zero at the moment of non-touch or touch, and then the vertical spring gradually plays a role when the displacement is increased, so that the phenomenon of unfavorable collision to shock insulation can not be generated.
Drawings
FIG. 1 is a general assembly view of the interior of the ultra low frequency seismic isolation apparatus of the present invention;
FIG. 2 is a cross-sectional view of the ultra low frequency seismic isolation apparatus of the present invention taken along the direction A-A;
FIG. 3 is a cross-sectional view of the ultra low frequency seismic isolation apparatus of the present invention taken along the direction B-B;
FIG. 4 is a side view of the ultra low frequency seismic isolation apparatus of the present invention;
FIG. 5 is a bottom assembly view of the ultra low frequency seismic isolation apparatus of the present invention;
FIG. 6 is a sectional view taken along the direction A-A of the lower assembly view of the ultra low frequency seismic isolation apparatus of the present invention;
FIG. 7 is a sectional view taken along the direction B-B of the lower assembly view of the ultra low frequency seismic isolation apparatus of the present invention;
FIG. 8 is an upper assembly view of the ultra low frequency seismic isolation apparatus of the present invention;
FIGS. 9 and 10 are sectional views of the upper layer of the ultra low frequency seismic isolation apparatus of the present invention;
FIG. 11 is a spring and connector of the present invention;
FIG. 12 is a graph of displacement versus stiffness variation for a seismic isolation system of the present invention;
FIG. 13 is a plot of the restoring force of the seismic isolation system of the present invention;
wherein, 1 is lower floor steel frame, 2 is lower floor linear guide, 3 is central slider, 4, 5 are lower floor's slider, 6 to 11 and 15 to 20 are the springs, 12 are upper strata linear guide 12, 13, 14 are upper strata slider, 21 are upper steel frame, 22 are cushion rubber pad.
Detailed Description
The invention provides an ultralow frequency shock isolation device and a performance evaluation method thereof, and provides a structural design of the shock isolation device, wherein the shock isolation device is arranged between the bottom of a shock-isolated object and a foundation, two shock isolation measures are set, a certain linear stiffness stroke is provided in an initial stage, the stiffness in the range is close to zero, the input of seismic energy can be obviously reduced in the range of the region, the local vibration energy is further increased, the sliding displacement of the device exceeds the linear stiffness stroke, the device enters a nonlinear shock isolation range at the moment, the stiffness in the range is nonlinearly increased from zero, the shock isolation device also has a shock isolation effect, the input of the seismic energy is further reduced, and the device can be restored to an initial state to achieve a reset function due to the action of the spring stiffness after the earthquake is ended. Through two shock insulation measures, the earthquake dynamic response of the shock insulation structure can be obviously reduced, the structural size and the economic cost of the device can be well controlled, and a safe and economic technical scheme is provided for the structural shock insulation control.
Example 1:
an ultra low frequency seismic isolation apparatus installed between the bottom of an object to be isolated and a foundation as shown in fig. 1, 2, 3 and 4, which are an overall view and sectional views in different directions, comprises: the upper layer shock insulation device, the lower layer shock insulation device and the elastic connecting piece are arranged in sequence; the upper layer shock isolation device and the lower layer shock isolation device are provided with horizontal sliding shock absorption units;
the elastic connection member is located between the sliding damping units.
Preferably, the upper layer seismic isolation apparatus includes: upper steel frame 21 and first slip shock attenuation unit, first slip shock attenuation unit includes: the upper layer linear guide rail 12, the upper layer sliding block and the upper layer elastic piece;
the upper layer linear guide rail 12 is fixedly connected to the upper layer steel frame 21;
the upper layer slide block and the elastic connecting piece are arranged on the upper layer linear guide rail 12;
one end of the upper layer elastic piece is connected with the upper layer sliding block, and the other end of the upper layer elastic piece is connected with the inner edge frame of the upper layer steel frame 21;
the upper layer steel frame 21 is connected with a vibration-isolated structure.
Preferably, the upper layer slider and the upper layer elastic member include a plurality of;
the number of the upper layer elastic pieces is twice of that of the upper layer sliding blocks.
Preferably, the lower layer seismic isolation apparatus includes: lower floor's steel frame 1 and second slip shock attenuation unit, the second slip shock attenuation unit includes: the lower linear guide rail 2, the lower sliding block and the lower elastic piece;
the lower-layer linear guide rail 2 is fixed on the lower-layer steel frame 1;
the lower layer slide block and the elastic connecting piece are arranged on the lower layer linear guide rail 2;
one end of the lower-layer elastic part is connected with the lower-layer sliding block, and the other end of the lower-layer elastic part is connected with the inner edge frame of the lower-layer steel frame 1;
the lower layer steel frame 1 is connected with a foundation.
Preferably, the number of the lower-layer sliding blocks and the number of the lower-layer elastic pieces are multiple;
the number of the lower layer elastic pieces is twice that of the lower layer sliding blocks.
Preferably, the elastic connection member includes: a central slider 3 and an elastic member;
the central sliding block 3 is arranged at the intersection point of the upper layer linear guide rail 12 and the lower layer linear guide rail 2;
the elastic piece comprises a first elastic piece and a second elastic piece;
the first elastic piece is arranged along the direction of the upper layer linear guide rail 12, one end of the first elastic piece is connected with the central sliding block 3, and the other end of the first elastic piece is connected with the inner frame of the upper layer linear guide rail 12;
the second elastic component is followed set up in 2 directions of lower floor's linear guide, one end with central slider 3 is connected, the other end with border connection in lower floor's steel frame 1.
Preferably, the first elastic member and the second elastic member each include a spring;
the spring adopts a tension and compression spring with the same specification.
Preferably, the central slider 3 has the same distance with the upper layer slider and the lower layer slider.
Preferably, the rubber cushion also comprises a buffer rubber cushion;
the connection part of the upper layer linear guide rail 12 and the inner side frame of the upper layer steel frame 21 is provided with the buffer rubber pad;
and the joint of the lower linear guide rail 2 and the inner frame of the lower steel frame 1 is provided with a buffer rubber pad. Preferably, the upper layer elastic member and the lower layer elastic member each include a spring
Example 2:
the invention will be further described with reference to fig. 1 to 13. The shock isolation device mainly comprises a lower layer steel frame 1, a lower layer linear guide rail 2, a central sliding block 3, lower layer sliding blocks 4 and 5, springs 6, 7, 8, 9, 10 and 11, an upper layer linear guide rail 12, upper layer sliding blocks 13 and 14, springs 15, 16, 17, 18, 19 and 20, an upper layer steel frame 21 and a buffer rubber pad 22.
The shock insulation device is of a double-layer structure, and comprises an upper layer shock insulation device, a lower layer shock insulation device and an elastic connecting piece; the upper layer shock isolation device and the lower layer shock isolation device are provided with horizontal sliding shock absorption units; the elastic connecting piece is positioned between the sliding damping units;
as shown in fig. 5, 6 and 7, and a sectional view of an underlayer-seismic isolation apparatus, which comprises: the lower steel frame 1 and a second sliding damping unit;
the lower layer steel frame 1 is connected with a foundation; the second sliding damping unit includes: the lower layer linear guide rail 2, the lower layer slide block 4, the lower layer slide block 5 and the lower layer elastic part; the lower layer elastic part adopts a spring 8, a spring 9, a spring 10 and a spring 11;
the elastic connecting piece comprises a central sliding block 3, a spring 6, a spring 7, a spring 15 and a spring 16;
lower floor's linear guide 2 fixed connection is on 1 bottom plate of lower floor's steel frame, and central slider 3 and lower floor's slider 4, lower floor's slider 5 are arranged on 2 upper portions of lower floor's linear guide, and spring 6, 7 are arranged along 2 directions of lower floor's linear guide to central slider 3, and lower floor's slider 4, 5 arranges spring 8, 9, 10, 11 in perpendicular lower floor's linear guide 2 directions, and 2 both ends of lower floor's linear guide and 1 within a definite time of lower floor's steel frame arrange rubber cushion pad, and central slider 3Arranged at a distance L from the sliding blocks 4 and 51The distance between the sliding blocks 4 and 5 and the cushion rubber pad 22 is L2。
As shown in fig. 8, 9 and 10, the upper-deck seismic isolation apparatus includes an upper-deck steel frame 21 and a first sliding damping unit; the first sliding damping unit includes: the upper layer linear guide rail 12, the upper layer sliding block and the upper layer elastic piece;
the upper layer elastic member herein includes: spring 17, spring 18, spring 19, spring 20;
the top of an upper layer steel frame 21 is connected with a shock insulation structure, an upper layer linear guide rail 12 is fixedly connected to a bottom plate of the upper layer steel frame 21, a central sliding block 3 and upper layer sliding blocks 13 and 14 are arranged on the upper portion of the upper layer linear guide rail 12, springs 15 and 16 are arranged on the central sliding block 3 along the direction of the upper layer linear guide rail 12, springs 17, 18, 19 and 20 are arranged on the upper layer sliding blocks 13 and 14 in the direction perpendicular to the direction of the lower layer linear guide rail 12, a buffer rubber pad is arranged between the two ends of the upper layer linear guide rail 12 and the upper layer steel frame 21, and the distance between the central sliding block 3 and the sliding blocks 13 and 14 is L1The distance between the sliding blocks 13 and 14 and the cushion rubber pad 22 is L2。
As shown in FIG. 11, the springs 6, 7, 15 and 16 are tension-compression springs of the same specification, and the spring rate K1(ii) a The springs 8, 9, 10, 11, 17, 18, 19 and 20 are tension springs with the same specification and have the rigidity of K2. Both ends of the spring are connected by pins, so that the assembly and disassembly are convenient.
(1) Description of seismic isolation
The shock insulation device is a horizontal orthogonal two-layer structure and can be used for all directions of horizontal earthquake action. The internal sliding of the vibration isolation device is mainly divided into two states, namely that the central sliding block 3 is not contacted with the sliding blocks 4, 5 or 13, 14, namely at-L1To L1Within the range, the linear stiffness range; secondly, when the local vibration energy is further increased, the displacement response of the central slide block 3 is increased, and the contact drives the slide blocks 4, 5 or 13, 14 to move, namely, at-L1-L2to-L1、L1To L1+L2Within the range, a non-linear stiffness range. It should be noted that the center slider3 when the sliding blocks 4, 5 or 13, 14 are contacted, because the springs connected with the sliding blocks 4, 5 or 13, 14 are vertical to the track, the rigidity and acting force along the track direction are zero at the moment of no contact or contact, and then the vertical springs gradually play a role when the displacement is increased, so that the phenomenon of unfavorable collision to shock insulation can not be generated.
The relation between the sliding displacement and the rigidity of the shock isolation device is shown in a formula (1):
the curve of the sliding displacement and the rigidity change is shown in FIG. 12, and K is in the linear rigidity range1The rigidity value is small, the seismic energy absorption of the seismic isolation device in the displacement range is very small, namely the function of the on-line rigidity range is seismic isolation, and the seismic isolation performance is obvious. In the nonlinear stiffness range, the system stiffness changes along with different displacements, belongs to the SD vibrator quasi-zero stiffness design theory, and also has good shock insulation effect, but the shock insulation performance is lower than the linear stiffness state, but the nonlinear stiffness range can better control the displacement response, namely the system stiffness can be used for shock insulation and displacement control in the nonlinear stiffness range. The combination of the two shock insulation measures can obviously improve the shock insulation efficiency of the shock insulation device.
Design parameter K1、K2、L1、L2Determining: k1The value is as small as possible, and 0.1 xK is recommended2. Other three parameters need to be arranged according to the earthquake fortification target and the device size (influence L)1And L2) And determining an optimal value by simulation calculation by adopting the relation of the formula (1).
(2) Self-reset functional description
Since the system is in the initial state, the restoring force is in the balanced state as shown in fig. 13, and the non-initial states are all in the force unbalanced state, the device can be restored to the initial state after the earthquake. The spring with the non-linear function is in an unstressed state under a normal state, the stress of the spring with the linear function is small, and the spring can well maintain the function under long-term working conditions.
(3) Description of the scope of application
Due to the linear stiffness and nonlinear stiffness design of the shock isolation device, the stiffness of the spring can be changed according to the shock-proof requirement of the upper structure, and the stiffness of the spring can be realized by selecting the stiffness change or combining a plurality of groups of springs, so that the shock isolation device is not influenced by the weight of a shock-isolated object and is suitable for the shock isolation requirement of each weight structure. The vibration isolation principle of the vibration isolation device can also be applied to mechanical vibration or wind-induced vibration control.
(4) The economic and environmental protection advantages are illustrated
The main components of the invention are the spring, the linear guide rail and the slide block, the cost of the components is low, the assembly mode is basically bolt connection and welding, the process requirement is simple, the processing cost of the device is low, and the influence on the environment is small.
Example 3:
based on the same invention concept, the invention also provides a design method of the ultralow frequency shock isolation device, which comprises the following steps:
sequentially determining an upper layer shock isolation device and a lower layer shock isolation device which are provided with sliding shock absorption units in the horizontal direction;
determining design parameters of a spring between sliding shock absorption units of an upper layer shock insulation device and a lower layer shock insulation device by using a stiffness equation based on the seismic intensity to be met and the displacement range of a shock insulation system installed on the ultralow frequency shock insulation device;
and the stiffness equation is determined by the relationship between the displacement of the vibration-isolated system and the stiffness change curve of the spring.
Preferably, the design parameters of the spring between the sliding shock absorption units of the upper-layer shock insulation device and the lower-layer shock insulation device, which are determined by using a stiffness equation based on the seismic intensity to be satisfied and the displacement range of the shock insulation system installed on the ultra-low frequency shock insulation device, include:
determining the rigidity in a rigidity equation set by using a system motion equation based on the seismic intensity required to be met by the designed ultralow frequency shock isolation device and the displacement range of the shock isolated system in combination with the mass of the shock isolated system;
determining the stiffness and the length of the initial state of the spring and the stiffness and the length of the spring parallel to the motion direction in the system based on the stiffness in the stiffness equation;
wherein the design parameters of the spring include: the initial state of the spring and its length, and the spring rate and length parallel to the direction of motion in the system.
Preferably, the stiffness equation is given by:
wherein l is the original length of the spring, d is the system displacement, and K1For spring rate parallel to the direction of motion in the system, K2The spring rate is perpendicular to the initial state of the motion direction in the system.
Preferably, the system motion equation is as follows:
wherein M is the mass of the object to be isolated; c is system damping; k is the dynamic stiffness of the system;
system acceleration;
the system speed; acc (t): is a seismic exciting force function.
The formula can be applied to finite element simulation calculation, when finite element modeling is carried out, a finite element model of a vibration-isolated object is arranged at the upper part, and a finite element model of a vibration-isolated system is arranged at the lower part, wherein the finite element model of the vibration-isolated system can be established by selecting a spring unit (or other units capable of realizing nonlinear rigidity) according to a system motion equation for simulation, and the relationship between the rigidity value of the unit and displacement is the system motion equation due to the nonlinear rigidity. This is also the method of applying the analysis in finite elements. Seismic waves are input into the integral finite element model, seismic response (acceleration, displacement or stress and the like) of the isolated object can be obtained through time-course calculation, and the seismic response can be compared with structural seismic response of an isolation-free system, so that the isolation efficiency is calculated, and the isolation performance is determined.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The present invention is not limited to the above embodiments, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention are included in the scope of the claims of the present invention which are filed as the application.
Claims (13)
1. An ultralow frequency vibration isolation device is arranged between the bottom of an object to be isolated and a foundation, and is characterized by comprising: the upper layer shock insulation device, the lower layer shock insulation device and the elastic connecting piece are arranged in sequence; the upper layer shock isolation device and the lower layer shock isolation device are provided with horizontal sliding shock absorption units;
the elastic connecting piece is positioned between the sliding damping units;
the elastic connection member includes: a central slider (3) and an elastic member;
the central sliding block (3) is arranged at the intersection point of an upper-layer linear guide rail (12) of the upper-layer shock isolation device and a lower-layer linear guide rail (2) of the lower-layer shock isolation device;
the elastic piece comprises a first elastic piece and a second elastic piece;
the first elastic piece is arranged along the direction of the upper layer linear guide rail (12), one end of the first elastic piece is connected with the central sliding block (3), and the other end of the first elastic piece is connected with an inner side frame of an upper layer steel frame (21) of the upper layer shock isolation device;
the second elastic piece is arranged along the direction of the lower-layer linear guide rail (2), one end of the second elastic piece is connected with the central sliding block (3), and the other end of the second elastic piece is connected with the inner side frame of the lower-layer steel frame (1) of the lower-layer shock isolation device.
2. The ultra low frequency seismic isolation system of claim 1 wherein said upper seismic isolation system comprises: an upper steel frame (21) and a first sliding damping unit, the first sliding damping unit comprising: the upper layer linear guide rail (12), the upper layer sliding block and the upper layer elastic piece;
the upper layer linear guide rail (12) is fixedly connected to the upper layer steel frame (21);
the upper layer sliding block and the elastic connecting piece are arranged on the upper layer linear guide rail (12);
one end of the upper layer elastic piece is connected with the upper layer sliding block, and the other end of the upper layer elastic piece is connected with the inner edge frame of the upper layer steel frame (21);
the upper layer steel frame (21) is connected with a vibration-isolated structure.
3. The ultra low frequency seismic isolation apparatus as claimed in claim 2, wherein said upper slider and said upper elastic member comprise a plurality;
the number of the upper layer elastic pieces is twice of that of the upper layer sliding blocks.
4. The ultra low frequency seismic isolation system of claim 2 wherein said lower seismic isolation system comprises: lower floor steel frame (1) and second slip shock attenuation unit, the second slip shock attenuation unit includes: the lower layer linear guide rail (2), the lower layer slide block and the lower layer elastic piece;
the lower-layer linear guide rail (2) is fixed on the lower-layer steel frame (1);
the lower-layer sliding block and the elastic connecting piece are arranged on the lower-layer linear guide rail (2);
one end of the lower-layer elastic part is connected with the lower-layer sliding block, and the other end of the lower-layer elastic part is connected with the inner edge frame of the lower-layer steel frame (1);
the lower layer steel frame (1) is connected with a foundation.
5. The ultra low frequency seismic isolation system of claim 4 wherein there are a plurality of said lower slider blocks and a plurality of said lower elastic members;
the number of the lower layer elastic pieces is twice that of the lower layer sliding blocks.
6. The ultra low frequency seismic isolation apparatus of claim 4, wherein said first elastic member and said second elastic member each comprise a spring;
the spring adopts a tension and compression spring with the same specification.
7. The ultra low frequency seismic isolation system as claimed in claim 4, wherein the center slider (3) is spaced at the same distance from the upper and lower sliders.
8. The ultra low frequency seismic isolation system of claim 6 further comprising a cushion rubber pad;
the connection part of the upper layer linear guide rail (12) and the inner edge frame of the upper layer steel frame (21) is provided with the buffer rubber pad;
and the joint of the lower linear guide rail (2) and the inner frame of the lower steel frame (1) is provided with a buffer rubber pad.
9. The ultra low frequency seismic isolation apparatus of claim 6 wherein said upper layer elastic member and said lower layer elastic member each comprise a spring.
10. A method of designing an ultra low frequency seismic isolation system as claimed in any of claims 1 to 9, comprising:
sequentially determining an upper layer shock isolation device and a lower layer shock isolation device which are provided with sliding shock absorption units in the horizontal direction;
determining design parameters of a spring of an elastic connecting piece positioned between sliding shock absorption units of an upper layer shock absorption device and a lower layer shock absorption device by utilizing a stiffness equation based on the seismic intensity to be met and the displacement range of a shock absorption system installed on the ultralow frequency shock absorption device;
and the stiffness equation is determined by the relationship between the displacement of the vibration-isolated system and the stiffness change curve of the spring.
11. The design method as set forth in claim 10, wherein the design parameters of the spring of the elastic connection member between the sliding shock-absorbing units of the upper-deck seismic-isolation apparatus and the lower-deck seismic-isolation apparatus, which are determined using the stiffness equation based on the seismic intensity to be satisfied and the displacement range of the seismic-isolation system mounted on the ultra-low frequency seismic-isolation apparatus, include:
determining the rigidity in a rigidity equation set by using a system motion equation based on the seismic intensity required to be met by the designed ultralow frequency shock isolation device and the displacement range of the shock isolated system in combination with the mass of the shock isolated system;
determining the stiffness and the length of the initial state of the spring and the stiffness and the length of the spring parallel to the motion direction in the system based on the stiffness in the stiffness equation;
wherein the design parameters of the spring include: the initial state of the spring and its length, and the spring rate and length parallel to the direction of motion in the system.
12. The design method of claim 11, wherein the stiffness equation is given by:
wherein l is the original length of the spring, d is the system displacement, and K1For spring rate parallel to the direction of motion in the system, K2Spring rate perpendicular to the initial state of the direction of motion in the system, L1And L2Is the linear stiffness.
13. The design method of claim 11, wherein the system equation of motion is given by:
wherein M is the mass of the object to be isolated; c is system damping; k is the dynamic stiffness of the system;
system acceleration;
the system speed; acc (t): is the earthquake exciting force function, and d is the system displacement.
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