Vibration response reduction device and vibration response reduction method

Abstract

To provide a vibration response reduction device capable of reducing a vibration response of a structure by bulging excited in a tank caused by vibration input from the structure, and to provide a vibration response reduction method.SOLUTION: A vibration response reduction device which reduces vibration amplitudes of a structure by excitation of a natural vibration mode includes a tank for storing a liquid inside. In the vibration response reduction device, the tank is constituted so as to excite a bulging mode which is a coupled vibration mode of a tank barrel plate and the liquid stored inside in the natural frequency of the structure.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vibration response reduction device and a vibration response reduction method for reducing the vibration response of an object such as a mechanical device. [Background technology]

[0002] In buildings, vehicles, machinery, etc., natural vibration modes may be excited due to disturbance loads such as wind, road conditions, and load fluctuations. In order to reduce the vibration response caused by the excitation of such natural vibration modes, vibration response reduction devices such as dynamic vibration absorbers and damper devices may be installed on objects such as buildings, vehicles, machinery, etc. Dynamic vibration absorbers and damper devices reduce the response magnification of the natural vibration modes of the object, but since they are installed in addition to the object, the weight of the object increases. This increase in weight may lead to a decrease in the natural frequency of the object, and the decrease in frequency may increase the amplitude and reduce the damping effect of the response acceleration. For this reason, it is desirable to configure a vibration response reduction device using a heavy object that is originally equipped on the object.

[0003] In response to this, Japanese Patent Laid-Open Publication No. 7-133681 (Patent Document 1) describes a vibration response reduction device that uses the sloshing of stored water in a water tank installed at the top of a high-rise building to form a dynamic vibration absorber. Sloshing is a relatively long-period vibration behavior in which the surface of liquid stored in a tank or the like fluctuates up and down, and the natural frequency is determined by the dimensions of the liquid surface and the depth of the liquid. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 7-133681 Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Document 1, in order to reduce the vibration response of a high-rise building due to wind loads, the sloshing frequency of a water tank installed on the roof is matched to the natural frequency of the building, making the water tank function as a dynamic vibration absorber.

[0006] However, this document assumes that the wall of the water tank is a rigid body and suppresses the vibration of the building by utilizing only the behavior of the stored water, without considering the deformation of the tank structure. Even if it is assumed that the water tank will deform due to the influence of sloshing of the stored water, it does not suggest at least a vibration response reduction mechanism that utilizes the vibration deformation of the water tank, or a structure that suppresses the vibration deformation of the vibration response reduction mechanism.

[0007] An object of the present invention is to provide a vibration response reduction device and a vibration response reduction method that can reduce the vibration response of a structure caused by bulging excited in a tank due to a vibration input from the structure. [Means for solving the problem]

[0008] In order to achieve the above-mentioned objective, the present invention provides a vibration response reduction device that reduces the vibration amplitude of a structure due to excitation of a natural vibration mode, the vibration response reduction device comprising a tank that stores liquid therein, the tank being configured to excite a bulging mode, which is a coupled vibration mode of the tank body and the liquid stored therein, at the natural vibration frequency of the structure. Effect of the Invention

[0009] According to the present invention, it is possible to reduce the vibration response of a structure caused by bulging excited in a tank due to a vibration input from the structure. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing a vibration response reduction device according to a first embodiment of the present invention; [Diagram 2] 1 is a flowchart showing a manufacturing procedure of a vibration response reduction device according to a first embodiment. [Diagram 3]FIG. 5 is a schematic diagram showing a vibration response reduction device according to a second embodiment of the present invention; [Figure 4] FIG. 5 is a schematic diagram showing a vibration response reduction device according to a third embodiment of the present invention; [Diagram 5] FIG. 13 is a schematic diagram showing a vibration response reduction device according to a fourth embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0012] (First embodiment) -Vibration response reduction device- Fig. 1 is a schematic diagram showing a vibration response reduction device 1 according to a first embodiment of the present invention. The vibration response reduction device 1 is a device that reduces the vibration amplitude of a structure caused by excitation of the natural vibration mode of the structure. The structure is a target structure for reducing the vibration response, and while Fig. 1 shows a mechanical device 2 as an example of a structure, the vibration response suppression device 1 can be applied to suppress the vibration amplitude of various structures such as buildings and frames.

[0013] The vibration response reduction device 1 includes a tank 10 that stores a liquid L therein, and a support member 20 that supports the tank 10 with respect to a mechanical device 2.

[0014] -tank- The tank 10 is a thin-walled container, and is preferably a container for storing therein the liquid L to be used by the mechanical device 2. Although the container that can be used as the tank 10 varies depending on the type of structure, for example, a surge tank, a buffer tank, a waste liquid tank, a fuel tank, a hydraulic oil tank, an oil tank, etc. can be used as the tank 10. The liquid L can be fuel, waste liquid, cooling water, lubricating oil, other water, etc., and any liquid necessary for the operation or operation of the structure can be used. The tank 10 can be configured by utilizing (modifying) a built-in container that was originally equipped in the structure, or can be replaced with a built-in container that was manufactured separately.

[0015] The tank 10 is typically cylindrical, and in this embodiment, is disposed in a position in which the center line C of the tank body 11 of the cylinder extends horizontally (left-right direction in FIG. 1). The tank 10 is disposed so that the center line C intersects (for example, is perpendicular to) the vibration direction V (direction perpendicular to the paper surface of FIG. 1) of the natural frequency of the main vibration mode of the mechanical device 2 to be suppressed, and the vibration direction V of the mechanical device 2 corresponds to the radial direction of the tank body 11.

[0016] The tank 10 is configured to excite a bulging mode, which is a coupled vibration mode of the tank body plate (the plate material constituting the tank body 11) and the liquid L stored therein, at the natural frequency of the mechanical device 2. For example, the diameter of the tank body 11 of the tank 10 is 300 times or more (e.g., 600 times) the plate thickness of the tank body plate, and the specific gravity of the liquid L stored in the tank 10 is 0.5 or more (1.0 for water). The length of the tank body 11 (length in the direction of the center line C) is 0.7 times or more (e.g., 1.0 times) the diameter of the tank body. Suitable examples of the material of the tank 10 include steel or aluminum alloy. The diameter / plate thickness ratio of the tank body 11, the specific gravity of the liquid L, and the upper limit of the length / diameter ratio of the tank body 11 are determined by the required strength of the tank 10 and the constraints of the installation space. Under these conditions, the dimensions of the tank 10 are set so that the bulging mode is easily excited at the natural frequency of the mechanical device 2 by fluid-structure coupled analysis. For example, when the natural frequency of the main vibration mode of the mechanical device 2 is about 100 Hz, the diameter of the tank body 11 can be set to about 300 mm, the length in the direction of the center line C to about 400 mm, and the thickness of the tank body plate to 0.3 to 0.5 mm, and the tank 10 can be manufactured from steel or aluminum alloy.

[0017] In the vibration response reduction device 1, since the liquid L does not need to slosh, if it is necessary to continue to feed the liquid L even under static acceleration conditions such as centrifugal force, or if disturbance of the motion behavior of the mechanical device 2 due to the swaying of the liquid L is a problem, a sponge-like structure 19 may be installed inside the tank 10. Furthermore, the liquid L does not need to be in direct contact with the inner circumferential surface of the tank body 11, and the bulging mode can be excited even if the liquid L is contained in the tank body 11 in a bag-like flexible container 18. For example, even if the liquid L is corrosive to the metal constituting the tank body plate, the liquid L can be stored in the tank 10 and the bulging mode can be excited by putting the liquid L in a flexible container 18 made of, for example, silicone resin, etc.

[0018] -Supporting member- The support member 20 has, for example, a flange-like structure, and supports the tank 10 near the joint between the tank body 11 and the head plates 12 attached to both ends of the tank body 11. Each support member 20 is firmly connected to the machine 2 at two linear joints by a construction method such as welding. This support member 20 is rigidly attached to the tank 10 in the vibration direction V in order to transmit the damping effect caused by bulging from the tank 10 to the machine 2. In other words, the joint structure between the support member 20 and the tank 10 has no play in the vibration direction V. On the other hand, it is preferable that the joint structure between the support member 20 and the tank 10 has play in the center line C direction of the tank 10 or is elastic. By configuring the tank 10 to be elastically supported in the center line direction, when the vibration of the machine 2 has a mode in the center line C direction, the tank 10 can act as a dynamic vibration absorber against the vibration mode in the center line C direction.

[0019] Although the support member 20 has been described as being flange-shaped, there are no particular limitations on the shape or quantity of the support member 20 as long as it can firmly install the tank 10 on the machinery 2. For example, instead of the configuration in which the head panels 12 on both sides are fixed to the machinery 2 as shown in Figure 1, a structure in which only one head panel 12 is fixed to the machinery 2 via the support member 20 and the other head panel 12 is directly fastened to the machinery 2 may also be used.

[0020] -Pressure device- In this embodiment, the vibration response reduction device 1 is provided with a pressurizing device 30, and the inside of the tank 10 can be pressurized by operating the pressurizing device 30. The pressurizing device 30 is, for example, a compressor, and an outlet is connected to the internal space of the tank 10 via a pipe 31. An exhaust pipe 32, the tip of which is open to the atmosphere, is connected to the middle of the pipe 31. A pressurizing valve 33 is provided on the pipe 31, and an exhaust valve 34 is provided on the exhaust pipe 32. The pressurizing valve 33 and the exhaust valve 34 constitute a pressure control valve. The pressurizing device 30, the pressurizing valve 33, and the exhaust valve 34 can be manually operated, and can also be controlled by a control device 40. The control device 40 is, for example, a computer, and can control the pressurizing device 30, the pressurizing valve 33, and the exhaust valve 34 in response to the output of an accelerometer 41 provided on the tank 10 and an accelerometer 42 provided on the mechanical device 2.

[0021] The tank 10 is thin-walled but must be able to withstand the bulging mode. For example, when the natural vibration mode of the machinery 2 is particularly likely to be excited during a transient operating state such as starting and stopping the machinery 2, the vibration condition of the machinery 2 during the transient operating state can be improved by the action of the vibration response reduction device 1. However, if the high-frequency bulging mode continues to be excited in the tank 10 even after the machinery 2 has entered a steady operating state and transitioned to a state in which the vibration response of the machinery 2 is no longer an issue, there is a possibility that the tank shell plate will be subjected to an excessive load due to high cycle fatigue.

[0022] Therefore, in this embodiment, the pressurizing device 30 is driven to open the pressurizing valve 33 with the exhaust valve 34 closed, and the internal pressure of the tank 10 is increased to apply tension to the tank body plate, thereby suppressing excitation of the bulging mode of the tank 10 due to vibration input from the mechanical device 2. For example, in order to excite the bulging mode of the tank 10 only during unsteady operation such as starting and stopping the mechanical device 2, the internal pressure of the tank 10 is increased by the pressurizing device 30 during steady operation of the mechanical device 2. Conversely, in order to excite the bulging mode of the tank 10 only during steady operation of the mechanical device 2, the internal pressure of the tank 10 is increased by the pressurizing device 30 during unsteady operation of the mechanical device 2. By stopping the pressurizing device 30, closing the pressurizing valve 33, and opening the exhaust valve 34, the inside of the tank 10 returns to atmospheric pressure, and the tank 10 returns to a state in which bulging can be excited.

[0023] For example, when a surge tank is used as the tank 10 and the coolant is liquid L, a valve that seals the tank 10 when the temperature of the coolant L rises can be provided as a pressure control valve, so that the inside of the tank 10 can be pressurized by utilizing the increase in vapor pressure of the liquid L during steady operation of the machine 2. In this case, the compressor as the pressurizing device 30 can be omitted.

[0024] Furthermore, if it is only necessary to automatically excite or not excite the bulging mode during non-steady or steady operation of the machinery 2, a signal related to the operation of the machinery 2 may be input to the control device 40 to control the pressurizing device 30, the pressurizing valve 33, and the exhaust valve 34. When non-steady / steady operation of the machinery 2 is detected based on the signal related to the operation of the machinery 2, the pressurizing device 30, the pressurizing valve 33, and the exhaust valve 34 are controlled.

[0025] Furthermore, the effect of suppressing the response vibration by the tank 10 can be optimized by controlling the pressurizing device 30, the pressurizing valve 33, and the exhaust valve 34 by the control device 40 based on the outputs of the accelerometers 41 and 42. In this case, a configuration can be exemplified in which the control device 40 calculates the amplitude of bulging of the tank 10 based on the output of the accelerometer 41, calculates the frequency of the mechanical device 2 based on the output of the accelerometer 42, and performs feedback control of the pressurizing device 30, the pressurizing valve 33, and the exhaust valve 34 so that, when any of the values ​​falls outside a preset optimum range, the value returns to the optimum range. For example, when the amplitude of bulging is excessively large during bulging excitation, the internal pressure of the tank 10 is increased to suppress the amplitude of bulging.

[0026] -effect- (1) Through extensive research, the inventors of the present application have discovered that bulging, i.e., vibration deformation of the tank 10, excited in the tank 10 by vibration input from the mechanical device 2 is effective in suppressing the vibration response of the mechanical device 2.

[0027] As described above, according to this embodiment, the tank 10 installed in the mechanical device 2 is excited into a natural vibration mode by vibration input from the mechanical device 2, and thereby a bulging mode, which is a coupled vibration mode of the tank body and the liquid L, is excited in the tank 10. By exciting the bulging mode at the natural vibration frequency of the mechanical device 2, the vibration response (response magnification) of the mechanical device 2 is suppressed by this bulging mode, and the amplitude of the vibration of the mechanical device 2 can be effectively suppressed, and deterioration of the performance and durability of the mechanical device 2 can be suppressed.

[0028] (2) Since the tank 10 is rigidly supported in the vibration direction V relative to the mechanical device 2, the excitation of the natural vibration mode of the mechanical device 2 and the bulging mode of the tank 10 can be rationally superimposed.

[0029] (3) Since the tank 10 stores the liquid L used by the machinery 2 inside, the tank 10 can also serve as the equipment that is necessary for the operation of the machinery 2 and that was originally installed on the machinery 2, thereby suppressing the increase in weight of the machinery 2.

[0030] (4) In this embodiment, by making the tank 10 cylindrical, a bulging mode (also called oval deformation) in which the cylindrical tank body 11 of the tank 10 undulates in the circumferential direction can be excited, and the natural frequency to be suppressed can be flexibly accommodated. In addition, by making the diameter / plate thickness ratio of the tank body 11 ≧300, the specific gravity of the liquid L ≧0.5, and the length / diameter ratio of the tank body 11 ≧0.7, an appropriate bulging effect can be obtained.

[0031] (5) Furthermore, in a situation where the response reduction effect of the mechanical device 2 is not required, the excitation of the bulging mode can be suppressed by increasing the internal pressure of the tank 10 using the pressurizing device 30. This makes it possible to suppress the application of more load than necessary to the tank 10 due to the excitation of unnecessary bulging modes.

[0032] (6) Since the tank 10 is horizontal, the increase in hoop stress due to hydrostatic pressure near the bottom can be suppressed, making it easier for the bulging mode to be excited.

[0033] (7) The vibration response reduction device 1 can be easily constructed by utilizing a tank that is originally provided in the mechanical device 2.

[0034] (8) Also, suppose that the mechanical device 2 is a device that does not cause a problem even if the liquid L sways for reasons such as the absence of static acceleration such as centrifugal force, and is configured not to transmit mechanical vibrations to the installation surface, or is configured to have a seismic isolation device interposed between the mechanical device 2 and the installation surface to reduce earthquake loads. In such a mechanical device 2, a rigid body vibration mode occurs at low vibration frequencies, and when the displacement becomes excessive, a load is applied to cables and piping connected to external equipment. In this case, by matching the sloshing frequency of the liquid L inside the tank 10 to the rigid body vibration mode, in addition to the effect of reducing the vibration response of the mechanical device 2 by the bulging mode of the tank 10, the vibration displacement due to the rigid body vibration mode can be reduced. The sloshing frequency of the liquid L inside the tank 10 can be adjusted by the surface area of ​​the liquid L (tank shape) and the water depth. Also, it is assumed that the sloshing frequency of the liquid L is significantly lower, about 1 / 100 of the bulging frequency. If the mechanical equipment 2 is seismically supported by a flexible mount, for example, and the natural frequency of the rigid body displacement mode of the entire mechanical equipment 2 including the vibration response reduction device 1 is about 1 Hz, the sloshing mode can also be used to reduce the rigid body mode response.

[0035] (9) Furthermore, when the structure to be subjected to vibration response reduction is, for example, a water tank installed on land, the structure itself to be subjected to vibration response reduction can also serve as the tank 10. In this case, just as in the case where the structure to be subjected to vibration response reduction is a building, it is expected that the water tank will be excited by, for example, an earthquake. Therefore, the water tank is manufactured as described above so that the bulging mode is excited at its own natural frequency. It is possible to reduce the response magnification of the sway mode, rocking mode, bending mode, etc. of the water tank by the action of bulging.

[0036] -Production procedure- Next, a flow for designing the dimensions of the tank 10 based on a fluid-structure interaction analysis will be described.

[0037] Fig. 2 is a flowchart showing the manufacturing procedure for the vibration response reduction device 1 according to this embodiment, in particular the evaluation procedure by fluid-structure interaction analysis for designing the tank body 11. The procedure shown in Fig. 2 represents the steps carried out by a designer or the like using a computer or the like as appropriate.

[0038] First, a modal analysis of the machine 2 is performed (step S11), the natural vibration mode that is the cause of the problematic vibration is estimated (step S12), and the position and vibration direction of the machine 2 where the response acceleration is large in that natural vibration mode is estimated (step S13). After that, the outer diameter and length limits of a cylinder that can be attached near the position where the response acceleration is large, with the vibration direction of the machine 2 being in the radial direction of the cylinder, are identified (step S14). In parallel with this, the vibration during operation of the machine 2 is actually measured (step S15), and the acceleration amplitude of the problematic vibration that occurs is recorded (step S16).

[0039] Next, the shape of the tank 10 is determined within the range where installation is possible ascertained in step S14, and the shape of the support member 20 is also determined (step S21). Then, the type of liquid L to be stored in the tank 10 is selected (step S22), and the type of liquid L is determined taking into consideration the convenience of piping and the like while preferentially selecting the liquid used in the mechanical device 2 (step S23). The piping is basically designed to be installed on the head plate 12 of the tank 10. Then, a temporary tank 10 is created and the liquid L is placed inside, and in this state, the natural frequency of the vibration mode that causes the problematic vibration of the mechanical device 2 is actually measured and confirmed (step S24). After that, the tank 10 is temporarily installed and a modal analysis is performed to confirm the natural frequency of the vibration mode that causes the problematic vibration (step S25). As an alternative method for this process, a method of preparing a weight having a mass equal to the sum of the mass of the support member 20 and 1 / 3 of the mass of the liquid L to be stored in the tank 10, attaching this weight to the planned installation position of the vibration response reduction device 1, and performing the modal analysis can also be adopted.

[0040] Next, the thickness of the tank body plate is designed under the condition that the diameter / thickness ratio is 300 or more for the outer diameter determined in step S21 (step S31), and a structural interaction analysis model is created (step S32). This structural analysis model is composed of only a simple circular tube with both ends fixed. In addition, a fluid analysis model is created separately (step S33). Then, based on the excitation amplitude obtained in step S16 and the frequency obtained in step S24, a simple harmonic acceleration excitation analysis is performed using a fluid-structure interaction analysis (step S34), and the presence or absence of bulging that exerts a response reduction effect is determined (step S35). Steps S31 to S35 can be efficiently performed by simultaneously setting multiple thicknesses of the tank body plate.

[0041] In the judgment of step S35, the criteria for determining whether effective bulging has occurred are that the radial acceleration waveform of the tank 10 has a high frequency of three times or more the input acceleration frequency, and the response magnification to the input acceleration amplitude is 40 times or more. In the judgment of step S35, if the difference in frequency between the input vibration and the bulging vibration is small, the rigidity of the tank 10 is considered to be insufficient, so the structural analysis model is changed by increasing the elastic coefficient of the tank body plate or increasing the plate thickness. If bulging does not occur, the rigidity of the tank body 11 is considered to be too high, so the structural analysis model is changed by decreasing the elastic coefficient of the tank body plate or decreasing the plate thickness. In addition, if there is a choice of liquid L, the setting of liquid L is changed to a type with a low density in order to increase the bulging frequency, and vice versa, to a type with a high density, and the fluid analysis model is changed. Then, the diameter, length, material of the body plate, plate thickness, and type of liquid L of the tank 10 with the largest response acceleration of the bulging deformation that can be expected to have a response reduction effect are recorded.

[0042] Steps S31-S34 are repeatedly performed by appropriately changing the structural analysis model and the physical properties of the liquid L, and when at least one candidate for the dimensions of the tank 10 and the physical properties of the liquid L is determined, the flow of Fig. 2 is terminated. By going through the steps of the flow of Fig. 2, the design of the tank 10 and the liquid L are determined.

[0043] Note that there are errors in fluid-structure interaction analysis, and manufacturing errors in the actual machine (the tank 10 that is actually produced). For this reason, the response obtained may not necessarily match the analysis results. However, the bulging mode exhibits a sufficient response reduction effect if it is in a frequency band close to the target frequency for response reduction, and can be adjusted by the liquid level height of the liquid L in the tank 10 and the internal pressure of the tank 10. Furthermore, because the structure of the tank 10 is simple, it is easy to first create a mockup and install it on the mechanical device 2 to check the excitation of bulging and the effect of reducing the vibration response, and then adjust the dimensions of the tank 10.

[0044] Second embodiment Fig. 3 is a schematic diagram showing a vibration response reducing device according to a second embodiment of the present invention, in which elements that are the same as or correspond to those in the already described embodiment are given the same reference numerals as in the already described drawings, and description thereof will be omitted.

[0045] The vibration response reduction device 1 of this embodiment differs from the vibration response reduction device 1 of the first embodiment in that the vibration response reduction device 1 of this embodiment includes a plurality of tanks 10A, 10B, each of which is independent of the other, and at least one of the ratio of the diameter of the tank body 11 to the plate thickness of the tank body plate and the ratio of the length of the tank body 11 to the diameter of the tank body 11 is different from the other. "The tanks 10A, 10B are independent from each other" means that the tanks 10A, 10B are not directly connected to each other by piping, and the liquid levels of the liquid L of the tanks L are not linked to each other and can be adjusted individually. The tanks 10A, 10B are configured such that at least one of the ratio of the diameter of the tank body 11 to the plate thickness of the tank body plate and the ratio of the length of the tank body 11 to the diameter of the tank body 11 is different from the other, and the bulging modes are excited at different natural frequencies of the mechanical device 2. In addition, since the tanks 10A and 10B are independent of each other as described above, by adjusting the liquid level (water depth) of the liquid L respectively, the natural frequencies related to the bulging modes of each of the tanks 10A and 10B can be adjusted separately.

[0046] In the example of FIG. 3, the tanks 10A and 10B are vertical cylindrical containers with the center line C extending vertically, and are fixed to the machine 2 via the support member 20 in a vertically aligned state. However, the tanks 10A and 10B may be horizontal cylindrical containers as in the first embodiment. Also, the tanks 10A and 10B are aligned vertically, but they may be aligned horizontally. However, the vertically aligned configuration can reduce the installation area of ​​the tanks 10A and 10B. Also, although a configuration having two tanks 10A and 10B is illustrated, the number of tanks may be three or more. Furthermore, the multiple tanks may be configured by dividing the chamber of one tank into multiple parts. The tanks 10A and 10B are designed and manufactured in the same manner as in the first embodiment.

[0047] In other respects, this embodiment is similar to the first embodiment. Although the control device 40, the pressurizing device 30, the spongy structure 19, the flexible container 18, the accelerometers 41 and 42, etc. are not particularly shown, these elements can be applied to this embodiment if necessary.

[0048] According to this embodiment, in addition to the same effects as those of the first embodiment, by having multiple independent tanks 10A, 10B with different natural frequencies related to the bulging mode, it is possible to obtain the advantage of being able to reduce vibration responses for multiple natural frequencies of the mechanical device 2. The vibration response reduction device 1 of this embodiment is effective when applied to a mechanical device 2 that does not require a large-capacity tank of a single structure.

[0049] In addition, in the case of a large vertical cylindrical tank, the hoop stress near the bottom increases due to hydrostatic pressure, which may make it difficult to excite the bulging mode. In contrast, in the present embodiment, although tanks 10A and 10B are both vertical cylindrical containers, there are multiple tanks, so their individual volumes and liquid levels are restricted, and the hydrostatic pressure in each tank can be reduced, making it easier to excite bulging deformation.

[0050] Third embodiment 4 is a schematic diagram showing a vibration response reducing device according to a third embodiment of the present invention, in which elements that are the same as or correspond to those in the previously described embodiments are given the same reference numerals as in the previously described drawings, and description thereof will be omitted.

[0051] The vibration response reduction device 1 of this embodiment differs from the vibration response reduction device 1 of the previously described embodiment in that the vibration response reduction device 1 of this embodiment is provided with multiple tanks 10C, 10D, each of which is connected to each other by piping 13, and at least one of the ratio of the diameter of the tank body 11 to the plate thickness of the tank body plate and the ratio of the length of the tank body 11 to the diameter of the tank body 11 is different from each other, and a height adjustment mechanism 21 is provided to adjust the height of at least one of the tanks 10C, 10D.

[0052] As in the second embodiment, the tanks 10C and 10D have different ratios of the diameter of the tank body 11 to the thickness of the tank body plate and the ratio of the length of the tank body 11 to the diameter of the tank body 11, so that the bulging modes are excited at different natural frequencies of the mechanical device 2. The tanks 10C and 10D are horizontally long cylindrical containers as in the first embodiment, but may be vertical cylindrical containers as in the second embodiment. Unlike FIG. 1, FIG. 4 shows the vibration response reduction device 1 as seen from a direction perpendicular to the vibration direction V. Also, FIG. 4 illustrates a configuration in which the tanks 10C and 10D are arranged parallel to the vibration direction V, but the layout can be changed as appropriate depending on the convenience of the tank installation space. For example, the tanks 10C and 10D may be arranged in tandem in a direction perpendicular to the vibration direction V. When the vibration directions V of the vibrations to be suppressed by the tanks 10C and 10D are different, the orientations of the tanks 10C and 10D may be different (the tanks 10C and 10D may be laid out so that their center lines C intersect in a plan view). The tanks 10C and 10D are also designed and manufactured in the same manner as in the first embodiment.

[0053] The internal spaces of the tanks 10C and 10D are connected to each other via the piping 13, and the liquid level (altitude) of the liquid L in each of the tanks 10C and 10D is the same. In this embodiment, a height adjustment mechanism 21 is provided on the support member 20 of the tank 10C, and when the height of the tank 10C is changed by the height adjustment mechanism 21, the height of the tank 10C changes with respect to the liquid level of the liquid L, and as a result, the liquid level (water depth) of the tanks 10C and 10D changes. This makes it possible to adjust the natural frequency related to the bulging mode of the tanks 10C and 10D. The height adjustment mechanism 21 is typically a hydraulic jack or a ball screw. It is desirable that the piping 13 is flexible so as to accommodate the displacement of the tank 10C.

[0054] The height adjustment mechanism can be operated manually, but can also be automatically controlled by the control device 40. For example, while bulging is excited in the tanks 10C, 10D, the amplitude of bulging in the tanks 10C, 10D and the frequency and direction of vibration of the mechanical device 2 can be calculated based on the outputs of the accelerometers 41, 42, and the height adjustment mechanism 21 can be controlled by the control device 40 to select which of the tanks 10C, 10D is to be excited with bulging, and to adjust the water depth of the selected tank so as to excite the bulging mode in that tank. Also, the height adjustment mechanism 21 can be feedback-controlled by the control device 40 so that the amplitude of bulging in the tanks 10C, 10D and the frequency of vibration of the mechanical device 2 are maintained within an appropriate range based on the outputs of the accelerometers 41, 42.

[0055] In other respects, this embodiment is similar to the first embodiment. Although the pressurizing device 30, the spongy structure 19, the flexible container 18, etc. are not particularly shown, these elements can be applied to this embodiment if necessary.

[0056] According to this embodiment, in addition to the same effects as those of the first embodiment, by having multiple independent tanks 10C, 10D with different natural frequencies related to the bulging mode, it is possible to obtain the advantage of being able to reduce vibration responses for multiple natural frequencies of the machinery 2. Furthermore, for example, by adjusting the water depth of the tanks 10C, 10D using the height adjustment mechanism 21 according to the operating conditions of the machinery 2, it is possible to excite bulging in a specific tank according to the vibration frequency and vibration direction of the machinery 2. This embodiment can be particularly effectively applied to a machinery 2 whose natural frequency and natural vibration mode change according to the operating conditions.

[0057] (Fourth embodiment) Fig. 5 is a schematic diagram showing a vibration response reduction device according to a fourth embodiment of the present invention, in which elements that are the same as or correspond to those in the already-described embodiments are given the same reference numerals as in the already-described drawings, and description thereof will be omitted.

[0058] The vibration response reduction device 1 of this embodiment differs from the vibration response reduction device 1 of the previously described embodiment in that the vibration response reduction device 1 of this embodiment is provided with a plurality of tanks 10E, 10F, 10G, 10H..., each tank 10E... is connected in a ring shape, and has a height adjustment mechanism 21 that adjusts the height of at least one of the tanks.

[0059] The tanks 10E, 10F... are cylindrical shells obtained by cutting straight pipes into a trapezoid in a plan view, and these tanks 10E, 10F... are joined together to form a torus shell shape. The tanks 10E, 10F... forming the torus shell shape each have a bulging mode. FIG. 5 shows half of the torus shell shape, and assumes a configuration in which eight tanks are joined in an annular shape, and illustrates four tanks 10E-10H. The number of tanks forming the torus shell shape can be changed as appropriate, and for example, 16 tanks may be joined to form the torus shell shape. The tanks 10E, 10F... are also designed and manufactured in the same manner as in the first embodiment. The tanks 10E, 10F... can be of the same design, or the diameter / thickness ratio, etc. can be made different as necessary.

[0060] Although one height adjustment mechanism 21 may be provided, it is preferable that a plurality of height adjustment mechanisms are provided in the circumferential direction of the torus shell shape. More preferably, three or more height adjustment mechanisms 21 are provided in the circumferential direction, in which case the torus shell shape can be freely tilted three-dimensionally. As in the third embodiment, the height adjustment mechanism can be manually operated or automatically controlled.

[0061] In other respects, this embodiment is similar to the first embodiment. Although the pressurizing device 30, the spongy structure 19, the flexible container 18, etc. are not particularly shown, these elements can be applied to this embodiment if necessary.

[0062] According to this embodiment, in addition to the same effects as those of the first embodiment, since each of the tanks 10E, 10F, etc., which are configured in a torus shell shape, has a bulging mode, it is possible to exert a vibration response reduction effect in all directions in the horizontal direction. Also, by adjusting the length of the support member 20 using the height adjustment mechanism 21 to tilt the torus shell, it is possible to change the water depth for each of the tanks 10E, 10F, etc., and freely change the bulging frequency. For example, a suppression chamber used in a nuclear reactor has a torus shell shape, and this can be exemplified as one application example of the vibration response reduction device 1 according to this embodiment.

[0063] (Modification) The present invention is not limited to the above-described embodiment, but includes various modified examples. For example, the above-described embodiment is specifically described in order to easily explain the present invention, and the present invention is not necessarily limited to all of the described configurations.

[0064] Also, a part of the configuration of one embodiment can be replaced with a part of the configuration of another embodiment. Also, the configuration of another embodiment can be added to the configuration of one embodiment. Also, a part of the configuration of each embodiment can be deleted, and a part of another configuration can be added or replaced with a part of another configuration. [Explanation of symbols]

[0065] 1... vibration response reduction device, 2... mechanical device (structure), 10, 10A-10H... tank, 11... tank body, 13... piping, 21... height adjustment mechanism, 30... pressure device, L... liquid, V... vibration direction

Claims

1. A vibration response reduction device that reduces a vibration amplitude of a structure due to excitation of a natural vibration mode, comprising: Equipped with a tank that stores liquid inside, The tank is configured to excite a bulging mode, which is a coupled vibration mode of the tank body and the liquid stored therein, at a natural frequency of the structure. Vibration response reduction device.

2. 2. The vibration response reducing device according to claim 1, A vibration response reduction device in which the tank is rigidly supported with respect to the structure in a vibration direction related to the natural frequency of the structure.

3. 2. The vibration response reducing device according to claim 1, The tank is a vibration response reduction device that stores liquid used in the structure.

4. 2. The vibration response reducing device according to claim 1, The tank is cylindrical, The diameter of the tank body is 300 times or more the thickness of the tank body plate, The specific gravity of the liquid stored in the tank is 0.5 or more. Vibration response reduction device.

5. 5. The vibration response reducing device according to claim 4, A vibration response reduction device, wherein the length of the tank body is 0.7 times or more the diameter of the tank body.

6. The vibration response reducing device according to claim 4, A vibration response reduction device having dimensions set so that a bulging mode is excited at the natural frequency of the structure by fluid-structure interaction analysis.

7. 2. The vibration response reducing device according to claim 1, A vibration response reduction device comprising a pressurizing device for pressurizing the inside of the tank.

8. 2. The vibration response reducing device according to claim 1, A plurality of the tanks are provided, The tanks are independent of each other, and at least one of the ratio of the diameter of the tank body to the thickness of the tank body plate and the ratio of the length of the tank body to the diameter is different from each other. Vibration response reduction device.

9. 2. The vibration response reducing device according to claim 1, A plurality of the tanks are provided, The tanks are connected to each other by piping, and at least one of the ratio of the diameter of the tank body to the plate thickness of the tank body plate and the ratio of the length to the diameter of the tank body is different from each other, A height adjustment mechanism is provided for adjusting the height of at least one tank. Vibration response reduction device.

10. 2. The vibration response reducing device according to claim 1, A plurality of the tanks are provided, The tanks are connected in a ring shape. Vibration response reduction device.

11. A vibration response reduction method for reducing a vibration amplitude of a structure due to excitation of a natural vibration mode, comprising the steps of: Using a tank that stores liquid inside, The tank is configured to excite a bulging mode, which is a coupled vibration mode of the tank body and the liquid stored therein, at a natural frequency of the structure. Vibration response reduction methods.

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