JP6168861B2 - Damping method, power plant using the same, and damping vibration system - Google Patents

Description

  The present invention relates to a damping method, a power plant using the damping method, and a damping vibration system.

  The technology for damping a structure is applied, for example, to prevent damage to a building by controlling shaking (vibration) caused by an earthquake. Technologies for damping structures include a method of rigidly supporting the object to be damped, a technique of adding energy with a damper to dissipate energy, a technique of using a dynamic vibration absorber, and controlling vibration with an active control device. Technology is common.

  In addition to the above technique, a technique for damping a structure using an inertial mass element has been proposed. The inertial mass element described here generates an inertial force proportional to the relative acceleration between installed elements.

  As an example of a structure damping technology using such an inertial mass element, for example, an inertial mass element that generates an inertial force according to the relative acceleration between each layer is used for a structure having a plurality of layers. Displacement transmission to the object to be controlled at a specific frequency due to the technology (Patent Document 1) that introduces a design method for setting the stimulation coefficient of the higher-order vibration mode of the structure to 0 (zero) and the inertial mass of the fluid There is a technique (Non-Patent Document 1) in which the rate is zero.

  More specifically, in the technique described in Non-Patent Document 1, a bypass pipe is installed so as to connect both ends of a cylinder in which a fluid is sealed, and fluids before and after the piston are connected from the outside of the cylinder. By utilizing the fact that the fluid in the bypass pipe moves at a high acceleration by the movement of the piston, a vibration damping effect based on the inertial resistance of the fluid is obtained. Further, by adjusting the value of the inertial mass obtained by the movement of the fluid, the displacement transmission rate at a specific frequency (frequency) is set to 0, and the structure is damped.

Japanese Patent Laid-Open No. 2005-213887

Taichi Matsuoka, “Vibration reduction device using inertial mass of fluid”, Proceedings of the Japan Society of Mechanical Engineers, November 2009 Edition C, Japan Society of Mechanical Engineers, November 25, 2009, Volumes 75, 759

  The technique described in Patent Document 1 is a technique for a multi-layered structure (vibration system) such as an apartment where the lower end is supported by the ground and the upper end is free. However, a structure (vibration system) that is affected by vibration due to earthquake motion is not limited to a structure in which the lower end is supported by the ground and the upper end is free.

  For example, a device that is rigidly disposed on the ground (hereinafter referred to as “non-seismic isolation device”) and a base that is isolated from the ground (a vibration control device that is a vibration control unit is interposed between the ground and the ground). Inserted equipment (hereinafter referred to as “Seismic Isolation Equipment”) on both ends of the ground, such as equipment systems (vibration systems) connected by low-flexible structures such as metal piping A connected vibration system can also be envisaged.

  The damping technique described in Patent Document 1 is not necessarily effective for a structure (vibration system) in which both ends are connected to the ground. That is, even if the vibration suppression technique described in Patent Document 1 is applied, the expected vibration suppression effect is not always obtained for a vibration system in which both ends are connected to the ground. Here, the low-flexible structure refers to a structure such as a metal pipe that has a rigid structure but allows a certain amount of elastic deformation.

  Further, in Non-Patent Document 1, since the displacement transmission rate can be set to 0 at a specific frequency using the inertial resistance of the fluid, it can be applied to a structure in which both ends are connected to the ground. However, the vibration suppression technique described in Non-Patent Document 1 cannot obtain a sufficient vibration suppression effect when vibration including a plurality of frequency components such as earthquake motion is input. Therefore, the technique described in Non-Patent Document 1 is not an effective vibration suppression technique as an earthquake countermeasure.

  The present invention has been made in view of the above-described circumstances, and two devices, one of which is damped to the ground and the other of which is rigidly disposed on the ground, and a low-flexible structure that connects them. It is an object of the present invention to provide a vibration damping method, a power plant using the vibration damping method, and a vibration damping vibration system that suppresses vibrations of the vibration system caused by earthquake motion by damping a vibration system composed of objects.

In order to solve the above-described problems, a vibration damping method according to an embodiment of the present invention is disposed via a first device that is rigidly disposed on the ground, and the ground and first vibration damping means. The second device is connected between the first device and the second device, and is longer than the distance at rest between the connection to the first device and the connection to the second device. In the vibration damping method including a low-flexibility structure, a second damping means is installed between the ground and the low-flexibility structure.

  In order to solve the above-described problems, a power plant according to an embodiment of the present invention uses the first equipment as a turbine building and the second equipment as a steam generation facility that generates steam supplied to the turbine building. The low-flexible structure is controlled by the above-described vibration suppression method as a steam pipe for supplying steam generated from the steam generation facility to the turbine building.

In order to solve the above-described problems, a vibration suppression vibration system according to an embodiment of the present invention is disposed via a first device that is rigidly disposed on the ground, and the ground and first vibration damping means. A distance between the second device, the first device, and the second device connected between the first device and the connection portion to the second device when stationary. In the vibration suppression vibration system including a long low-flexibility structure, a second vibration suppression unit is provided between the ground and the low-flexibility structure.

  According to the present invention, it is possible to suppress the vibration of the vibration system due to the earthquake motion.

Schematic which showed the example of application of the damping device which concerns on embodiment of this invention. Schematic which shows the vibration model which modeled the vibration system (FIG. 1) to which the damping device concerning embodiment of this invention was applied. In the vibration damping method (vibration damping device) according to the embodiment of the present invention, the absolute value of the stimulation coefficient β ₂ of the secondary vibration mode with respect to the dimensionless parameter μ _S proportional to the inertia mass m _S of the inertia mass element is shown. Illustration (graph). In the vibration damping method (vibration damping device) according to the embodiment of the present invention, an explanatory diagram (graph) showing the absolute value of the vibration mode stimulation coefficient β with respect to the dimensionless parameter μ _S proportional to the inertia mass m _S of the inertia mass element ). It is explanatory drawing explaining the effect | action and effect of the damping device which concerns on embodiment of this invention, (A) Change of the load to a structure in case the damping device which concerns on embodiment of this invention is not applied Explanatory drawing which shows the result of having analyzed this, (B) Explanatory drawing which shows the result of having analyzed the transition of the load to a structure at the time of applying the damping device which concerns on embodiment of this invention.

  Hereinafter, a vibration damping method, a power plant using the vibration damping method, and a vibration damping system according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is an application example of a vibration damping device 1 that is an example of a vibration damping vibration system according to an embodiment of the present invention, and is a schematic diagram illustrating a vibration damping vibration system 10 that is vibration-damped by the vibration damping device 1. .

  The vibration damping device 1 includes, for example, an object (hereinafter referred to as “non-seismic isolation object”) 12 that is rigidly disposed on the ground 11 (without using a seismic isolation device) and the ground 11. An object 14 (hereinafter referred to as an “isolation object”) 14 that is seismically isolated by inserting a seismic isolation device 13 or the like as a first damping means between the The present invention is applied to a vibration system in which both ends of a vibration suppression vibration system 10 connected via a pipe 17 which is an example of a flexible structure are connected (fixed) to the ground 11 (or the wall surface of the non-seismic isolation object 12). .

  Some examples of the vibration suppression vibration system 10 shown in FIG. 1 include, for example, a plurality of buildings including at least one seismic isolation building, and piping equipment (crossover piping) connecting the plurality of buildings. Seismic isolation objects such as emergency diesel generators installed on part or all of systems such as power plants and industrial plants, and seismic isolation devices installed in factories, etc. An emergency power generation system or the like that is connected to the emergency diesel generator through a pipe and includes a non-seismic isolation object such as a fuel tank. When applied to a power plant, the base-isolated building that has been seismically isolated can be provided with steam generating equipment such as a nuclear reactor, for example.

  In the vibration suppression vibration system 10 as shown in FIG. 1, when an earthquake occurs, the seismic isolation object 14 is seismically isolated by the seismic isolation device 13 and is slowly displaced greatly (so-called long-period vibration is generated). Also, the pipe 17 that connects the non-isolation object 12 at one end and the isolation object 14 at the other end takes into account the displacement of the non-isolation object 12 and the isolation object 14 caused by an earthquake or the like. For example, a bent portion that is bent in a straight line or a curved portion that is bent in a curved shape is provided to provide a margin. By providing a margin for such a bent portion or the like, the displacement of the pipe 17 due to long-period vibration is absorbed so that the pipe 17 is not damaged. That is, the length of the pipe 17 that is a low-flexibility structure is the length of the connection part where the pipe 17 is connected to the non-seismic isolation object 12 and the connection part where the pipe 17 is connected to the seismic isolation object 14. By taking longer than the stationary distance between the two, a margin is provided, thereby realizing a certain degree of flexibility.

  However, as a result of providing a margin such as a bent portion, the pipe 17 becomes longer and the resonance frequency of the pipe 17 is lowered. When the resonance frequency of the pipe 17 is lowered to the vicinity of the vibration frequency range, the pipe 17 resonates during an earthquake and is greatly displaced (short-period vibration) in a shorter cycle than the long-period vibration caused by the earthquake motion. For this reason, even if the pipe 17 absorbs the displacement due to the long-period vibration of the earthquake motion by the flexibility, the pipe 17 which is a low-flexible structure may generate a short-period vibration due to the resonance of the pipe 17 itself. Concerned.

  The damping device 1 can suppress the resonance of the pipe 17, which is a short-period vibration, while allowing the long-period vibration of the pipe 17 by damping the vibration caused by the earthquake motion propagating from the ground 11 to the pipe 17. . In the present embodiment shown in FIG. 1, the vibration damping device 1 is provided between the ground 11 and the pipe 17. However, as described above, the non-seismic isolation object 12 is rigidly disposed on the ground 11. Therefore, the vibration damping device 1 may be provided between the non-seismic isolation object 12 and the pipe 17.

  In addition, piping described in this specification, such as piping 17, means a tubular structure (tubular structure), and is not limited by the name. For example, a tubular structure whose name is not “xx piping”, such as “xx duct”, also corresponds to “piping” described in this specification.

  In addition, the low-flexibility structure refers to a structure such as a metal pipe that has a rigid structure but allows a certain amount of elastic deformation. Here, the piping 17 which is a low-flexible structure has a natural frequency of the natural frequency of the base isolation object 14 with respect to the ground 11, that is, the natural frequency of the base isolation object 14 placed on the base isolation device 13. It is higher than the frequency (the natural frequency of the vibration element composed of the seismic isolation device 13 and the seismic isolation object 14) and lower than the natural frequency of the non-base isolation object 12 with respect to the ground 11. That is, it can be said that the low-flexibility structure has a natural frequency in this range.

  FIG. 2 is a schematic diagram showing a vibration model 20 obtained by modeling the vibration suppression vibration system 10 shown in FIG.

  The vibration model 20 includes a rigid wall 21 (left side in the figure) corresponding to the ground 11 in FIG. 1 and a first mass element 31 by a first spring 41, and the rigid body wall 21 (right side in the figure) and a second mass. This is a two-mass system model configured by connecting the element 32 with a second spring 42 and connecting the first mass element 31 and the second mass element 32 with a third spring 43. An inertia mass element 34 inserted in parallel with the first spring 41 is connected between the rigid wall 21 (left side in the figure) and the first mass element 31.

  The first mass element 31, the second mass element 32, and the inertial mass element 34 connect the non-seismic isolation object 12 and the seismic isolation object 14 respectively in the vibration suppression vibration system 10 (FIG. 1). This corresponds to the vibration damping device 1 that suppresses the resonance of the piping 17 as the low-flexibility structure, the seismic isolation object 14, and the piping 17 during the earthquake.

  Here, of the two vibration modes in the vibration model 20 (two-mass system model), the primary mode corresponds to the movement of the seismic isolation object 14 and the secondary mode corresponds to the resonance of the pipe 17 itself. The stimulus coefficient described later is a stimulus coefficient for the secondary mode unless otherwise specified.

2, the symbols u, x ₁ , and x ₂ represent the displacement amount of the ground 11, the displacement amount of the first mass element 31, and the displacement amount of the second mass element 32, respectively. It is. Further, the symbols m ₁ , m ₂ , and m _S represent the equivalent mass of the low-flexibility structure (pipe 17), the mass of the seismic isolation object 14, and the control in the vibration mode (secondary mode) of interest. This is the inertial mass of the inertial mass element 34 that can be adjusted by the vibration device 1. The inertia mass element 34 described in the present specification generates an inertia force proportional to the relative acceleration between installed elements.

Furthermore, reference numerals k ₁ , k ₂ , and k ₃ denote the equivalent rigidity of the non-base isolation object 12 side and the equivalent rigidity of the base isolation device 13 with respect to the equivalent mass m ₁ of the low-flexibility structure (pipe 17), respectively. , And the equivalent stiffness on the seismic isolation object 14 side with respect to the equivalent mass m ₁ of the low-flexibility structure (pipe 17). In the vibration model 20 (two-mass system model), This corresponds to the spring constant of the springs 41, 42, 43. Note that m ₁ , k ₁ , and k ₃ can be obtained by analysis, respectively.

The vibration suppression method and the vibration suppression vibration system according to the embodiment of the present invention adjusts (optimizes) the value of the inertia mass m _S of the inertia mass element 34 in the vibration model 20 as described above, so that the target vibration mode This minimizes the stimulation coefficient of (secondary mode).

  The configuration of the vibration damping system according to the embodiment of the present invention is arbitrary as long as it satisfies the function of generating an inertial force proportional to the relative acceleration between the installed elements. For example, according to the embodiment of the present invention, various methods are used such as one that uses the inertial mass of the fluid or one that obtains an inertial mass larger than the mass of the actual mass using the inertial moment of the mass. A vibration damping device can be configured.

Subsequently, an optimization method (first optimization method and second optimization method) of the inertial mass m _S in the vibration model 20 will be described.

[First optimization method]
In the vibration model 20, the inertial mass element 34 disposed between the first mass element 31 and the rigid wall 21 has an inertial force proportional to the relative acceleration between the first mass element 31 and the rigid wall 21. Is generated. The equation of motion for the first mass element 31 of the vibration model 20 can be expressed by the following equation (1).

In this equation (2), inertial mass m _S is added for the inertia term, while m _S is not added for the external force term. Therefore, it can be seen that the inertial term is affected by m _S , but the external force term is not affected by m _S. This is because the inertial force is proportional to the relative acceleration between the first mass element 31 and the rigid wall 21, and the inertial force generated by the first mass element 31 itself is proportional to the absolute acceleration.

  Next, considering the case where there is no external force, the natural frequency and the natural mode vector are obtained. The equation of motion can be expressed by the following equation (5).

In the first optimization method, the equation (13) the absolute value of the minimum value of the stimulation index beta ₂ represented, as more preferably zero (beta _{2 =} 0), the inertial mass of the inertial mass element 34 m _S is adjusted and the inertial mass m _S is optimized.

Subsequently, an example of optimization calculation of the inertia mass m _S using the above formula (13) will be shown, and the optimization of the inertia mass m _S in the first optimization method will be described.

FIG. 3 is an explanatory diagram (graph) showing the absolute value of the stimulation coefficient β ₂ of the second-order vibration mode with respect to the dimensionless parameter μ _S proportional to the inertia mass m _S of the inertia mass element 34.

In the graph shown in FIG. 3, the dimensionless parameters μ _I , ν _I , and α are μ _I = 5, ν _I = 0.1, and α = 0.5, respectively.

According to the graph shown in FIG. 3, the mu _S is mu _{S =} 0.86 a horizontal axis, that the absolute value of the stimulation index beta ₂ is a vertical axis represents the 0 seen. Under the above conditions, μ _S = 0.86, that is, the inertia mass m _S of the inertia mass element 34 is set to 0.86 times m ₁ of the first mass element 31 (m _S = 0.86 m ₁ ). By doing so, the stimulation coefficient β ₂ (absolute value) can be set to zero.

Thus, the excitation of the vibration mode is suppressed by setting the inertia mass m _S of the inertia mass element 34 so that the absolute value of the stimulation coefficient β ₂ is as small as possible (in this case, β ₂ = 0). be able to.

The absolute value of the stimulation index beta ₂ may not necessarily be the minimum value, the simulation arbitrarily set as long as effectively tolerance less capable of suppressing the resonance derived from the results and the like. However, the smaller the absolute value of the stimulation coefficient β ₂ is, the lower the influence on the input vibration is. Therefore, even if the absolute value of the stimulation coefficient β ₂ cannot be set to β ₂ = 0. The minimum value is more preferable, and when β ₂ = 0 can be set, 0 is further preferable.

Also, the graph shown in FIG. 3 is an example, and the values of the dimensionless parameters μ _I , ν _I , α as conditions for calculating the stimulation coefficient β ₂ do not necessarily match those in the above example. The values of these dimensionless parameters μ _I , ν _I , α vary depending on conditions.

[Second optimization method]
The second optimization method is based on the first optimization method, but using an equation different from the first optimization method, the inertia mass m of the inertia mass element 34 is simpler than the first optimization method. Optimize _S. More specifically, when there is a large difference in rigidity and mass between the first and second mass elements 31 and 32 that are the two vibrating bodies of the vibration model 20 (FIG. 2), the above-described equation (13) is further simplified. The inertia mass m _S of the inertia mass element 34 is optimized using the formula (formula (25) described later).

Subsequently, an example of optimization calculation of the inertial mass m _S using the above formula (26) will be shown, and the optimization of the inertial mass m _S in the second optimization method will be described.

FIG. 4 is an explanatory diagram (graph) showing the absolute value of the vibration mode stimulation coefficient β with respect to the dimensionless parameter μ _S proportional to the inertia mass m _S of the inertia mass element 34.

In the graph shown in FIG. 4, the solid line represents the absolute value of the stimulation coefficient β of the vibration mode with respect to the dimensionless parameter μ _S proportional to the inertia mass m _S of the inertia mass element 34 obtained by the second optimization method, and the broken line represents The absolute value of the second-order vibration mode stimulation coefficient β ₂ with respect to the dimensionless parameter μ _S proportional to the inertia mass m _S of the inertia mass element 34 obtained by the first optimization method is shown.

The other dimensionless parameters μ _I , ν _I , α are μ _I = 100, ν _I = 0.1, and α = 0.5, respectively.

When the solid line and the broken line shown in FIG. 4 are compared, it can be confirmed that the two calculation results indicated by the solid line and the broken line are in good agreement. Therefore, when the dimensionless parameters ν _I and μ _I satisfy the above-described expressions (15a) and (15b), that is, when the conditions expressed by the above-described expressions (14a) and (14b) are satisfied. For example, the second optimization method for optimizing the inertial mass m _S of the inertial mass element 34 by minimizing the absolute value of the stimulation coefficient β expressed by the above equation (26) is simple and effective. You can say that.

Therefore, when the conditions shown by the above-described equations (14a) and (14b) and k ₁ = k ₃ are satisfied, if the inertia mass m _S is set as m _S = m ₁ , the stimulation coefficient β Can be set to 0 which is the minimum value. Thus, when the conditions shown by the above-described equations (14a) and (14b) are satisfied, the inertial mass m _S of the inertial mass element 34 can be optimized more easily.

  Next, the action and effect of damping by the damping method and damping vibration system according to the embodiment of the present invention will be described.

  FIG. 5 is an explanatory diagram for explaining a difference in vibration between the case where the vibration damping device 1 is applied and the case where the vibration damping device 1 is not applied. FIG. FIG. 5B is an explanatory diagram illustrating a result of analyzing the transition of the load, and FIG. 5B is an explanatory diagram illustrating a result of analyzing the transition of the load to the structure when the vibration damping device 1 is not applied. Note that reference numerals R1 and R2 shown in FIG. 5A are time domains, and correspond to the time domains R1 and R2 shown in FIG. 5B, respectively.

  In the waveform shown in FIG. 5 (A), a waveform having a short period corresponding to the vibration associated with resonance of a structure such as a pipe is superimposed on a waveform having a long period corresponding to the period of the swing of the seismic isolation object. In the time regions R1 and R2, a waveform having a short period is observed. On the other hand, in the time regions R1 and R2 shown in FIG. 5B, it can be seen that there is no waveform having a short period corresponding to the vibration associated with resonance, which is suppressed.

  Therefore, if the vibration damping device 1 is applied, the vibration damping device 1 absorbs (allows) the vibration of the seismic isolation object, while suppressing the short-period vibration accompanying the resonance. Damage to objects can be minimized.

  For example, in a system (for example, a power plant, a chemical plant, a food plant, etc.) in which devices connected by a low-flexible tubular structure are arranged over a plurality of buildings, non-seismic isolation is installed on the ground. One end of the plant equipment installed in the building and the other end of the plant equipment installed in the base-isolated building that has been seismically isolated, penetrate the walls of the non-base-isolated building and the base-isolated building. In addition, if two plant devices located at both ends are connected via non-flexible piping whose overall length is longer than the length between both plant devices located at both ends, If the apparatus 1 is installed and applied, a long-period fluctuation corresponding to the period of the oscillation of the seismic isolation object caused by the earthquake motion can be absorbed and a short-period fluctuation accompanying the resonance can be suppressed. In situations where damage may occur Prevent raw, it can keep the integrity of the entire plant.

  As described above, according to the vibration suppression method and the vibration suppression vibration system according to the embodiment of the present invention, the vibration-isolating object caused by the ground motion is suppressed by suppressing the structure constituting the vibration system in which both ends are connected to the ground. Since the vibration with a long period corresponding to the period of the object's vibration can be absorbed and the vibration with a short period due to resonance can be suppressed, the occurrence of a situation in which the structure is damaged by the vibration can be prevented, and the entire system can be prevented. Soundness can be maintained.

  Further, according to the power plant according to the embodiment of the present invention, that is, the power plant to which the vibration damping device (or vibration damping method) according to the embodiment of the present invention is applied, the piping 17 (FIG. 1) due to long-period vibration is used. Since short-period vibration can be suppressed while absorbing the displacement, vibration of the plant main part including the piping 17 can be suppressed in the event of an earthquake, etc., and the soundness of the entire power plant can be reduced. Can keep.

  It should be noted that the present invention is not limited to the above-described embodiment as it is, and can be implemented in various forms other than the above-described examples in the implementation stage, and various modifications can be made without departing from the spirit of the invention. Can be omitted, added, replaced, or changed. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

For example, with respect to the vibration damping method and the like according to an embodiment of the present invention, in the optimization method of the inertial mass m _S described above, performed by setting the value of the inertial mass m _S of the absolute value of the stimulation index is the minimum value However, it is not always necessary to set the absolute value of the stimulation coefficient to a minimum value, and any value other than the minimum value can be set as long as it is within a range of values that can effectively suppress resonance. .

  DESCRIPTION OF SYMBOLS 1 ... Damping device, 10 ... Damping vibration system, 11 ... Ground, 12 ... Non seismic isolation object, 13 ... Seismic isolation device, 14 ... Seismic isolation object, 17 ... Piping (low flexible structure), DESCRIPTION OF SYMBOLS 20 ... Vibration model, 21 ... Rigid body wall, 31 ... 1st mass element, 32 ... 2nd mass element, 34 ... Inertial mass element, 41 ... 1st spring, 42 ... 2nd spring, 43 ... 3rd Spring.

Claims (6)

Between the first device rigidly disposed on the ground, the second device disposed via the ground and the first vibration damping means, and between the first device and the second device. In a vibration damping method for a vibration system comprising a low-flexible structure that is longer than a stationary distance between a connection portion to the first device and a connection portion to the second device,
A vibration damping method, wherein a second vibration damping means is installed between the ground and the low flexibility structure.   2. The vibration damping method according to claim 1, wherein the second damping unit suppresses resonance generated in the low-flexibility structure due to shaking of the ground. 3. .   2. The vibration damping method according to claim 1, wherein the second damping means generates an inertial force proportional to a relative acceleration between the ground and the second device.   The first device is a turbine building, the second device is a steam generating facility that generates steam supplied to the turbine building, and the low-flexible structure is connected to the steam generating facility and the turbine building. A power plant that is damped by the vibration damping method according to claim 1 as a pipe to be laid. Between the first device rigidly disposed on the ground, the second device disposed via the ground and the first damping means, and between the first device and the second device In a vibration-damping vibration system comprising a low-flexible structure longer than the distance at rest between the connection to the first device and the connection to the second device,
A vibration damping vibration system characterized in that second vibration damping means is provided between the ground and the low flexible structure.   6. The vibration damping system according to claim 5, wherein the second damping means is configured to generate an inertial force proportional to a relative acceleration between the ground and the second device. Damping vibration system.

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