JP2011012427A - Initial displacement-imparted tmd vibration control system for building - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive and easy-to-mount TMD vibration control system for a building, which enhances a response reducing effect at the initial stage of transient response of a vibration control device (TMD) installed on the rooftop of the building and on its indoor side, and which exerts a great vibration control effect.SOLUTION: This vibration control system includes: the vibration control device (TMD) which comprises a weight acting in the direction of canceling seismic-ground-motion input into the building during earthquakes, and a spring and a damper, interposed between the weight and the building; and a trigger device 4 which keeps the vibration control device in a locked state, and which puts the vibration control device into an unlocked state during the earthquakes. The spring of the TMD is preliminarily expanded/contracted by a predetermined length; and initial displacement, which is set using a change in the phase of an envelope curve of "beat" generated by the superposition of a plurality of vibration modes having natural frequencies set close to one another and generated near a vibration mode in the case of the single building, is imparted by the addition of the TMD, maintained by the trigger device 4, and released from the initial displacement by releasing the locked state during the earthquake.

Description

The present invention relates to a vibration damping system provided with an initial displacement imparting type TMD capable of enhancing the vibration damping effect at the beginning of transient response in a building.

As a vibration control method when earthquake motion is applied to a building, an active vibration control method and a passive vibration control method are taken. The active vibration control method is a method of controlling the vibration of a building due to a disturbance by forcibly moving a weight so as to cancel the disturbance using an actuator. However, this control method requires a large amount of external energy to operate the actuator, which not only lengthens the vibration control device, but also creates a dangerous instability phenomenon such as spillover due to lower dimensions. Since there is a possibility, a complicated control law for controlling the actuator is also required.

As a passive type vibration control method, there is one in which a TMD is provided in a building. This TMD is composed of a weight, a spring, and a damper, and is attached to the structure to resonate and vibrate greatly to absorb the vibration energy of the structure as the kinetic energy of the weight and to dissipate the energy by the damping force of the damper. It is a control method. Since this TMD does not require a fulcrum, it has a high degree of freedom in designing. Has a proven track record in many fields, including measures against environmental vibration of large span floor slabs.

However, since the damping effect of TMD is based on a steady state, it is known that the damping effect of TMD against unsteady ground motion is not so great. In particular, when subjected to earthquake motion, the vibration control effect of the building to which the TMD is attached in the early response cannot be expected. This is because in passive TMD, there is no external energy to force the weight to move, so the damping effect does not appear until the weight starts to move itself by disturbance (seismic motion) and reaches a stable vibration state. It is. This is a major issue that makes it difficult to apply TMD to earthquake motion.

There are many patent documents that use passive type TMD in buildings to control response to seismic force, but by applying initial displacement to TMD, the response reduction effect when receiving impact force that is a typical transient response Prior art to be improved is only described in Non-Patent Document 1 and Non-Patent Document 2 below. These two documents use TMD's phase change of the “beat” envelope generated by the superposition of two (or more) adjacent vibration modes generated by attaching a TMD to a building. There is no disclosure of a method for greatly increasing the response reduction effect in the initial transient response by controlling the magnitude of the initial displacement.

M.Abe and T.Igusa: Semi-Active Dynamic Vibration Absorbers for Controlling Transient Response, Journal of Sound and Vibration, Vol.198 (5), pp.547-569, 1996. Nobuo Tanaka “Vibration Control” Yokendo 2008

The present invention applies an initial displacement to a spring of a vibration damping device (TMD) installed on the roof of a building or indoors by a predetermined length in advance and maintains the initial displacement with a trigger device. Releasing the locked state to release the initial displacement, and giving the initial displacement of the TMD appropriately at that time greatly enhances the response reduction effect at the initial stage of the transient response. The purpose is to provide a vibration control system.

A building initial displacement imparting TMD vibration damping system according to claim 1 of the present invention is a vibration damping system installed on the roof of a building or indoors, and the vibration damping system receives an input seismic motion to the building during an earthquake. A damping device (TMD) comprising a weight acting in a direction to cancel out the vibration, a spring and a damper interposed between the heavy water and the building, and maintaining the damping device in a locked state so that it locks in the event of an earthquake The TMD spring includes a trigger device to be released, and a plurality of vibration modes having close natural frequencies generated in the vicinity of the vibration mode of a single building by the addition of TMD are superimposed on the TMD spring in advance. The initial displacement set by using the phase change of the “beat” envelope generated by this is given and the initial displacement is maintained by the trigger device, and the locked state is released at the time of the earthquake and the initial displacement It is characterized by being released.

Since TMD provided in conventional vibration-damping buildings is based on steady-state vibration damping effects, it has been found that TMD vibration-damping effects against unsteady ground motion are not very large. In particular, when subjected to earthquake motion, the vibration control effect of the building to which the TMD is attached in the early response cannot be expected. This is because in passive TMD, there is no external energy to force the weight to move, so the damping effect does not appear until the weight starts to move itself by disturbance (seismic motion) and reaches a stable vibration state. It is. This is a major problem that makes it difficult to apply TMD to earthquake motion.

However, the TMD of the present invention is not intended to improve the damping effect simply by giving an initial displacement, but the phase of the “beat” envelope generated by the superposition of a plurality of vibration modes having close natural frequencies. It uses change. Specifically, by attaching one TMD to a building, two vibration modes having a natural frequency close to each other in the vicinity of the vibration mode for a single building are newly generated. When these two vibration modes are superimposed on the time history, a “beat” occurs. In this case, if a plurality of TMDs are attached to the building, a vibration mode corresponding to the number is newly generated. By applying the initial displacement of TMD, the phase of the “beat” envelope can be changed, and the time history response curve can be controlled. Here, if the initial displacement of the TMD is set large, the response reduction effect immediately after receiving the impact force can be greatly increased. When the initial displacement is set to be small, the response reduction effect immediately after receiving the impact force is slightly inferior to the case where the initial displacement is large, but the response reduction effect over the entire time history can be greatly enhanced. Therefore, the designer can control the time history response curve by changing the magnitude of the initial displacement according to the design purpose.

FIG. 1 compares the frequency response curves when the structure is a single body and when one TMD is attached to the structure. As shown in FIG. 1, by attaching one TMD, two vibration modes of A mode and B mode are generated with a small frequency difference on both sides of the natural frequency of the vibration mode when the structure is a single body. . When two TMDs are attached, three vibration modes are generated. These two vibration modes of the A mode and the B mode are superposed on the response time history, thereby generating a “beat”. The present invention uses the region where the amplitude of the envelope gradually decreases during the “beat” cycle, and controls the time when the amplitude decreases by the magnitude of the initial displacement of the TMD, thereby reducing the initial response of the transient response. It has the feature that the effect can be greatly enhanced, and the spring is given an initial displacement (pre-stress) in consideration of “beat” in advance, and the weight is released at an appropriate time during the input of the earthquake external force The present invention provides a TMD damping system for a building that exhibits a higher damping effect than a TMD provided in a conventional damping structure by using a simple mechanism.

ただし、ｙ₀は初期変位（ｍ）、ω_aは制振建物とＴＭＤの固有円振動数の平均値、ｘ₀はトリガーを解放する閾値として設定した制振建物の応答速度である。式中の（−）は制振建物の振動方向と逆の向き（ＴＭＤの振幅が大きくなる向き）に初期変位ｙ₀を与えることを示す。初期変位の単位はm、速度の単位はm/secである。 The building initial displacement imparting type TMD vibration control system according to claim 2 of the present invention is the building according to claim 1, wherein the initial displacement is divided by the coefficient α relating to the magnitude of the phase change of the beat envelope. These are set using the following two approximate expressions.

However, y ₀ is the initial displacement (m), ω _a is the average value of the natural circular frequencies of the damping building and TMD, and x ₀ is the response speed of the damping building set as a threshold for releasing the trigger. (-) In the equation indicates that the initial displacement y ₀ is applied in the direction opposite to the vibration direction of the damping building (the direction in which the amplitude of TMD increases). The unit of initial displacement is m, and the unit of velocity is m / sec.

According to the above configuration, the initial displacement for expanding and contracting the TMD spring in advance by a predetermined length can be easily performed by using the expression (1) divided by the magnitude of the coefficient α related to the magnitude of the phase change of the beat envelope. Can be set.

According to a third aspect of the present invention, there is provided an initial displacement imparting type TMD vibration control system according to a first aspect of the present invention, wherein the trigger device receives a signal from an earthquake detection device that detects vibration during an earthquake, It is characterized by a control device that sometimes releases the locked state of the trigger device.

According to the above configuration, the trigger device receives a signal from the earthquake sensing device that detects the vibration at the time of the earthquake and releases the locked state of the trigger device at the time of the earthquake, so according to the magnitude of the vibration at the time of the earthquake. The trigger device can be adjusted not only to be unlocked but also to be unlocked after an arbitrary time has elapsed since the occurrence of the earthquake.

According to a fourth aspect of the present invention, there is provided an initial displacement imparting type TMD vibration control system according to the first aspect, wherein the initial displacement imparting type TMD control system includes the vibration damping device (TMD) and the trigger device in a building. It is characterized in that at least two vibration systems are provided.

According to the above configuration, since at least two initial displacement imparting TMD vibration control systems including the vibration control device (TMD) and the trigger device are provided in the building, for example, in the case of a multi-layered frame structure such as a building In addition to being distributed in different layers to enable vibration control for each layer, adjust the release timing of each trigger device of multiple initial displacement imparted TMD vibration control systems installed in the building By doing so, it is possible to cope with multiple aftershocks that come after the main shock. In this case, if the trigger device receives a signal from an earthquake sensing device that detects vibration during an earthquake and releases the locked state of the trigger device during an earthquake, the control can be performed more reliably.

Since the initial displacement imparting type TMD vibration control system of the building of the present invention has the above-described configuration, it is not intended to improve the damping effect by simply applying the initial displacement to the TMD spring in advance, but to the TMD to the building. Due to the addition, the initial displacement set using the phase change of the “beat” envelope generated by the superposition of multiple vibration modes with close natural frequencies is attached, so it is inexpensive to install. It is possible to provide a TMD vibration control device for a building having an easy and high vibration suppression effect.

It is the conceptual diagram which showed the comparison of the frequency response curve in the case of a structure single-piece | unit, and the case where TMD is attached to a structure. It is explanatory drawing which showed the structure of the damping building. It is explanatory drawing which showed how to give the initial displacement of a damping device. It is explanatory drawing which showed the relationship between coefficient (alpha) and TMD initial displacement. It is explanatory drawing which showed the control flow of initial displacement provision type | mold TMD. It is explanatory drawing which showed the method of dividing | segmenting TMD into several pieces. It is explanatory drawing which showed the method of arrange | positioning the divided | segmented TMD in the space | distribution type in space. It is explanatory drawing which showed the control flow at the time of dividing | segmenting TMD into two. It is explanatory drawing which showed the structure of the TMD apparatus using a motor. It is explanatory drawing which showed the control flow at the time of using a motor.

A simple mechanism that applies an initial displacement (pre-stress) to the spring in advance and releases the weight at an appropriate time of the earthquake input with the aim of improving the vibration reduction effect in the initial transient response, which is a weak point of TMD. It was realized by using.

FIG. 2 shows a structure of a vibration control building where the initial displacement imparting type TMD is installed. The device of the initial displacement imparting type TMD includes a weight 1, a spring 2, a damper 3, and a trigger device 4. The spring 2 and the damper 3 have a vibration control building as a fulcrum, and a weight 1 is connected to the other end. The weight 1 is about 1-2% of the building weight. The natural circular frequency ω _{T of the} spring 2 and the damping ratio ξ _T of the damper 3 are formulas (3), (4), and (5) that are calculation formulas for optimization with respect to generally used harmonic ground vibration. ). When an earthquake occurs and the vibration of the damping building starts, the response of the damping building is observed by the earthquake sensor 5 installed in the damping building and input to the control device 6. The seismic sensor 5 is installed in a place where the response is expected to be greatest in the building obtained as a result of the analysis performed at the time of design, or is installed in a distributed manner in several places in the damping building. The control device 6 outputs the response speed of the damping building. When the seismic sensor 5 is installed at several places, the maximum or average value of the response speeds at several places is obtained and used as the response speed of the damping building. When the response speed of the damping building is below a certain threshold, the trigger device 4 is locked and the damping device does not operate. When the response speed threshold set at the time of design is exceeded, the trigger device 4 is unlocked, the weight 1 is released, the vibration control device is activated, and the response of the vibration control building is controlled. In this embodiment, the unlocking of the trigger device 4 is controlled by the seismic sensor 5 and the control device 6, but this is performed without using the seismic sensor 5 and the control device 6. 4 is made of a material that breaks due to an earthquake load, and when the load due to the earthquake acts on the trigger device 4, the trigger device 4 is broken and unlocked, and then the weight 1 is released and the vibration damping device is released. It may be configured to operate.

ここで、ω_sは制振建物の制御モードにおける固有円振動数、μは重錘１の質量比である。質量比μは重錘１の質量ｍの制振建物の制御モードにおける等価質量Ｍに対する比である。

Here, ω _s is the natural circular frequency in the control mode of the damping building, and μ is the mass ratio of the weight 1. The mass ratio μ is the ratio of the mass m of the weight 1 to the equivalent mass M in the control mode of the damping building.

Weight 1 of the damping device, the state when no earthquake normal is spring 2 is stretchable from a state 7 stretching no spring to a predetermined length as shown in FIG. 3 the initial displacement y ₀ granted 8 And is locked by the trigger device 4.

ω_aは制振建物とＴＭＤの固有円振動数の平均値、ｘ₀はトリガーを解放する閾値として設定した制振建物の応答速度である。式中の（−）は制振建物の振動方向と逆の向き（ＴＭＤの振幅が大きくなる向き）に初期変位ｙ₀を与えることを示す。初期変位の単位はm、速度の単位はm/secである。 The initial displacement y ₀ is set using a coefficient α related to the magnitude of the phase change of the “beat” envelope resulting from the superposition of the two vibration modes generated by incorporating TMD into the structure in response time history. To do. When α is increased, the region where the amplitude of the envelope of “growing” is small moves to the front of the time history, so that the response control effect immediately after releasing the trigger is very good, but the response in the latter period becomes larger. When α is small, the response control effect immediately after releasing the trigger is slightly inferior to that when α is large, but the response over the entire time history is well controlled. Normally, α is set between 0.2 and 1.0. FIG. 4 shows the relationship between the coefficient α and (ω _a · y ₀ / x ₀ ) at 2.0%, which is a general mass ratio of TMD installed in a building. ω _a is the average value of the natural circular frequencies of the damping building and the TMD, and x ₀ is the response speed of the damping building set as a threshold for releasing the trigger. Practically, FIG. 4 is calculated using a linear approximation, and the initial displacement y ₀ is divided by the coefficient α related to the magnitude of the phase change of the “beat” envelope, and the following 2 It sets using the type | formula (1) or (2).

ω _a is the average value of the natural circular frequencies of the damping building and the TMD, and x ₀ is the response speed of the damping building set as a threshold for releasing the trigger. (-) In the equation indicates that the initial displacement y ₀ is applied in the direction opposite to the vibration direction of the damping building (the direction in which the amplitude of TMD increases). The unit of initial displacement is m, and the unit of velocity is m / sec.

FIG. 5 shows a control flow of the initial displacement imparting type TMD of the present invention. When the response speed of the damping building is small, such as a small earthquake motion, the trigger is maintained without being released, and the damping device does not operate. When the response speed of the vibration-damped building exceeds the control target speed for releasing the trigger 4, which is the threshold set at the time of design, as in the case of a large earthquake, trigger 4 is set at the peak response speed in the time history. Release and activate the damping device.

When it is difficult to completely control the response of the damping building by releasing the initial displacement only once over the entire loading time, such as when receiving earthquake motion with a long duration. The operation of giving and releasing the initial displacement is performed two or more times.

As a means for releasing the initial displacement a plurality of times, there is a method of dividing the TMD into several pieces. As shown in FIG. 6, several small TMDs having initial displacements are prepared, and when the damping building reaches a control target speed that is a threshold value of the trigger device 4, the small size is sequentially reduced in a preset order. Release one TMD at a time.

The TMDs may be arranged in a distributed manner in the space as shown in FIG. In the case of a multi-layered frame structure such as a building, it may be arranged in a distributed manner not on the same floor but on different floors.

FIG. 8 shows a control flow when the TMD is divided into two.

Other examples

As a means for releasing the initial displacement a plurality of times, as shown in FIG. 9, a motor 9 and a wire 10 are attached between the weight and the fulcrum, and the spring is contracted by the motor 9 so that the initial displacement is applied to the weight 1. There is a method of repeating a locked state in which the motor 9 is locked and a state in which the motor 9 is unlocked. This method requires a motor power source, but the initial displacement can be released any number of times.

In order to move the weight 1 to the position of the predetermined initial displacement after releasing the weight 1, a working time of the motor is required. Therefore, when the set time Δt has elapsed after the TMD is unlocked, the weight 1 is locked once, and the time interval until the damping building reaches the control target speed that is the threshold value of the trigger 4 again is set to the time interval of the motor. The working time is set, and the weight 1 is released again after the structure reaches the control target speed. Δt is a time during which the damping effect of the initial displacement imparting TMD is higher than that of a general TMD having no initial displacement. When the TMD mass ratio μ is 2.0% and the coefficient α is 1.0, Δt is set to 1.31 seconds. FIG. 10 shows a control flow of this method.

Since it is possible to provide a vibration control device that has a high vibration control effect and is inexpensive and easy to install, it can be used for seismic reinforcement against earthquakes in high-rise buildings and detached houses, etc. The use of large-span floor slabs with frequent occurrence as a measure against environmental vibration is also expected. Since TMD does not require a fulcrum, it has a high degree of design freedom and is effective for application to a large span roof structure with a complicated shape.

DESCRIPTION OF SYMBOLS 1 Weight 2 Spring 3 Damper 4 Trigger device 5 Seismic sensor 6 Control device 7 Weight position before applying initial displacement 8 Weight position after applying initial displacement 9 Motor 10 Wire

Claims (4)

A vibration damping system installed on the roof or indoors of a building, wherein the vibration damping system includes a weight acting in a direction to cancel an input ground motion to the building at the time of an earthquake, and an interposed between the weight and the building. A damping device (TMD) comprising a spring and a damper, and a trigger device for maintaining the damping device in a locked state and releasing the lock in the event of an earthquake. The initial displacement set by using the phase change of the “beat” envelope generated by the superposition of multiple vibration modes close to the natural frequency generated in the vicinity of the vibration mode of a single building due to the addition of TMD And the initial displacement is maintained by a trigger device, and the initial displacement is released by releasing the initial displacement in the event of an earthquake. The building according to claim 1, wherein the initial displacement is set using the following two approximate expressions, divided by the magnitude of the coefficient α related to the magnitude of the phase change of the beat envelope. An initial displacement imparting type TMD vibration control system.

However, y ₀ is the initial displacement (m), ω _a is the average value of the natural circular frequencies of the damping building and TMD, and x ₀ is the response speed of the damping building set as a threshold for releasing the trigger. (-) In the equation indicates that the initial displacement y ₀ is applied in the direction opposite to the vibration direction of the damping building (the direction in which the amplitude of TMD increases). The unit of initial displacement is m, and the unit of velocity is m / sec. The said trigger apparatus is provided with the control apparatus which receives the signal from the earthquake detection apparatus which detects the vibration at the time of an earthquake, and cancels | releases the locked state of a trigger apparatus at the time of an earthquake. TMD vibration control system with initial displacement for buildings. The building according to any one of claims 1 to 3, wherein at least two or more initial displacement imparting TMD damping systems including the damping device (TMD) and the trigger device are provided in the building. Initial displacement imparted TMD vibration control system.

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