JPS63172030A - Vibration damping device - Google Patents

Abstract

PURPOSE:To damp vibrations of large and small amplitudes so as to improve the vibration damping performance by providing elasto-plastic members for damping vibration in a moving system and friction force generating members between a fixed member locked in a stationary system and a supporting member for supporting the moving system. CONSTITUTION:In a fixed rod 23 as a fixed member and a supporting rod 25 as a moving member are provided with connecting holes 31, 35 and flat-faced portions 33, 37 respectively, and on both sides of the flat-faced portions 33, 37 are arranged plural plates 27 along the axes of both rods 23, 25 at equally intervals. One end of each of the plates 27 is locked to each of the flat-faced portions 33, 37 and the other end is locked to each of connecting plates 39, thus both rods 23 and 25 being elasto-plastically connected to each other. Between both flat-faced portions 33 and 37, a guide 29 is locked to the flat-faced portion 33 and fitted to the flat-faced portion 37 through a shim so that the contact face pressure can be adjusted by adjusting bolts 47. Thus, vibrations of large and small amplitudes are favorably damped, so that the vibration damping performance can be improved and fatigue failure of the elasto-plastic member can also be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a vibration damping bag U that supports a movable system such as a piping system and damps vibrations of the movable system.

(Prior Art) Plant piping systems vibrate due to earthquakes and external forces from rotating equipment. There is a vibration damping device that supports such a vibrating piping system and damps the vibration. This vibration damping device is in this case a pipe support device. Conventional pipe support devices include, for example, oil snappers and mechanical snappers.

However, since these have complicated structures, quality control is complicated and costs increase. In order to solve these drawbacks, piping support devices that utilize the plastic strain energy of materials have been proposed.

FIG. 10 and FIG. 11 are a front view and a sectional view, respectively, showing a conventional pipe support device that utilizes plastic strain energy.

The pipe 1 is supported via a connecting rod 3 by a plurality of plates 5 as elastic-plastic members. These plates 5 are
As shown in FIG. 12, the plate 5 is formed to have a wide width at both ends and a narrow width at the center so that the stress distribution in the thickness direction of the plate 5 is uniform. Further, the other ends of the plurality of plates 5 are fixed to the cover 7. An attachment 9 is integrally or integrally attached to the cover 7, and this attachment 9 is supported by a building or other structure.

In such a pipe support device, in response to thermal expansion of the pipe 1, the plate 5 is elastically deformed and acts as a spring.
Absorbs deformation due to thermal expansion.

In addition, if a large load is applied to the pipe 1 during an earthquake, etc.,
The vibrations caused by the large load are damped by plastic strain energy due to yielding of the plate 5.

Note that a bottle 11 is implanted in the plate 5.

This pin 11 is designed so that even if an excessive force is applied to the plate 5 through the connecting rod 3, the pin 11 will come into contact with the end of the locking hole 13 of the cover 7 and function as a limit switch. Prevent photopic destruction of h5. It is something.

(Problems to be Solved by the Invention) As described above, in the conventional pipe support device, a large load within the plastic region of the plate 5 acts on the pipe 1 with a large amplitude.
When the pipe 1 vibrates, the vibration of the pipe 1 can be damped by the plastic strain energy of the plate 5.

However, if a load within the elastic range of the plate 5 acts on the pipe 1 and the pipe 1 vibrates with a small amplitude, the small amplitude vibration cannot be damped by plastic strain energy.

For such small-amplitude imaging, there is no other option but to attenuate it by elastic deformation of the plate 5. However, plate 5
The problem with damping by elastic deformation is that small amplitude vibrations cannot be sufficiently damped.

In addition, since it is not possible to sufficiently attenuate small amplitude and high frequency vibrations, the plate 5
The plate 5 becomes fatigued due to repeated loads acting on the
There is a risk of destruction.

This invention was made in consideration of the above facts, and even when a large load within the plastic region is applied to a small amplitude vibration that occurs when a load within the elastic region of an elasto-plastic member is applied. It is possible to suitably damp the large amplitude vibrations that occur, improve vibration damping performance, and
It is an object of the present invention to provide a vibration damping device that can prevent fatigue failure of elastic-plastic members.

[Structure of the invention]

(Means for Solving the Problems) The present invention includes a fixed member fixed to a stationary system, a supporting member supporting a movable system, and a fixed member attached between the fixed member and the supporting member to apply plastic strain energy to the movable system. The F? generated between an elastic-plastic member that damps the vibrations of the above-mentioned fixed member and at least one of the supporting members and at least one of these members. The movable system includes a friction force generating member that damps vibrations of the movable system using friction force.

(Function) Therefore, the vibration damping device according to the present invention uses the plastic strain energy of the elastoplastic member to damp vibrations of large amplitude that occur when a load within the plastic region of the elastoplastic member acts on the movable system. Attenuated, small-amplitude vibrations that occur when a load within the elastic range of an elasto-plastic member acts on a movable system can be suppressed by the friction that occurs between at least one of the fixed member or the supporting member and the frictional force generating member. Attenuate the shooting by force. In this way, both small vibrations and large vibration amplitudes can be suitably damped.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a front view showing an embodiment of a vibration damping device according to the present invention.

The piping support device 21 as a vibration damping device includes a fixed rod 23 as a fixed member, a support rod 25 as a support member, a plate 27 as an elastic-plastic member, and a guide 29 as a friction force generating member. It consists of

The fixing rod 23 has a fixing connection hole 31 on one end side,
The other end side is formed into a flat portion 33 as shown in FIG.

On the other hand, the support rod 25 is also configured in substantially the same manner as the fixed rod 23, and has a support connecting hole 35 and a flat portion 37.

The fixing connection hole 31 is for fixing the fixing rod 23 to a structure or the like (not shown) as a stationary system. Further, the support connecting hole 35 is for connecting the support rod 25 to a piping system (not shown) or the like as a movable system to support the piping system or the like.

A plurality of plates 2 are provided on both sides of the flat parts 33 and 37.
7 are arranged at approximately equal intervals in the axial direction of the fixed rod 23 and the support rod 25. Each plate 1-27 is fixed at one end to the flat portion 33.37 and at the other end to the connecting plate 33.37.
is fixed to. This connection plate 39 connects the fixed rod 23 and the support rod 25 via the plate 27.

Therefore, when a load acts between the fixed rod 23 and the support rod 25, the plate 27 is elastically or plastically deformed, and the fixed rod 23 and the support rod 25 move toward or away from each other in their axial directions. The distance between the flat portions 33, 27 of the fixed rod 23 and the support ITI rod 25 is set so that the fixed rod 23 and the support rod 25 do not come into contact even if they approach each other.

The number of plates 27 arranged is selected depending on the piping dimensions of the piping system, thermal conditions, seismic load, etc. Each plate 27
is made of steel, for example, and its width is widest at both ends in the longitudinal direction and narrowest at the center, as shown in FIG. This shape makes the stress distribution generated in the thickness direction of the plate 27 uniform.

On the other hand, the flat portion 3 of the fixed rod 23 and the support rod 25
3.371:! J is provided with guides 29 on both sides of these flat portions 33°37. The guide 29 has a U-shaped cross section as shown in FIGS. 2 and 3, and is provided so as to cover the side surfaces of the flat portions 33 and 37. This guide 29 is fixed to the flat portion 33 of the fixed rod 23 with bolts 41 and a lug 43. Further, the guide 29 is provided in contact with the side surface of the flat portion 37 of the support rod 25 so as to be movable in layers.

A shim 45 as shown in FIG. 4 is disposed between the guide 29 and the side surface of the flat portion 37. As shown in FIG. Further, an adjustment bolt 47 is screwed onto the abutting surface of the guide 29. A recess 49 is formed in the shim 45, and the tip of the adjustment bolt 47 is fitted into the four recesses 49. By adjusting the threaded suspension of the adjustment bolt 47, the surface pressure between the side surface of the flat portion 37 and the shim 45 can be varied.
Adjust the magnitude of the frictional force R generated between the The frictional force R has an equivalent damping constant he (encroachment) of the critical damping (he=1
).

Now, when a load is applied between the fixed rod 23 and the support rod 25, the plate 27 exhibits elastic-plastic restoring force characteristics as shown in FIG. Load from piping ff1Q and play 1~
The relationship between 27 and the displacement X is as follows. When the load Q acts, the plate 27 undergoes elastic deformation at its initial rigidity until it reaches the yield point A1. Once the yield point A1 is reached, plastic deformation continues until the point A is reached even if no load Q is applied. When a load Q in the opposite direction acts at point A2, deformation proportional to the load progresses from point A2 toward point A3. Below, point A, point A
and is displaced according to a history loop connecting point A1.

Further, when a load is applied between the fixed rod 23 and the support rod 25, the support rod 25 vibrates relative to the fixed rod 23, and a frictional force R is generated between the flat portion 33 of the support rod 25 and the shim 45. FIG. 6 shows a history loop of restoring force characteristics due to vibration accompanied by friction. Displacement X does not occur from point OB to point B1 due to frictional force R. When a load exceeding this Il friction force R acts, a displacement X occurs from point B1 toward point B2 against this rs friction force R. Even if a load in the opposite direction is applied at point B2, no displacement occurs due to the am force R, and displacement occurs when a load exceeding point B3 is applied. Thereafter, displacement follows a history loop connecting points B4, B5, and B1.

Therefore, the restoring force characteristic of the pipe support device 21 becomes the history loop shown by the solid curve [151 in FIG. 7], which is the sum of the history loops in FIGS. 5 and 6. In other words, point O
From to point A, the fixed rod 23 and the support rod 25
Even if a load Q acts between them, a frictional force R is generated between the flat portion 37 and the shim 45, and no displacement X occurs. When a load Q exceeding point A is applied to the plate 27, the plate 27 loses its initial rigidity and is displaced to a yield point B. When the yield point B is reached, plastic deformation progresses even if no load is applied, and the point C is reached. Load I in the opposite direction from point C
When Q acts, frictional force R is generated again between flat portion 33 and shim 45, and displacement X does not occur.

Hereinafter, transformation is performed according to an employment history loop connecting points E1, F1, G, J5, and H.

Therefore, when a load is applied to the fixed rod 23 and the support rod 25, the vibration energy is dissipated by the frictional force R generated between the flat portion 33 and the shim 45, and the vibration energy is further absorbed as the plate 27 undergoes plastic strain deformation. . Note that the broken line curve 53 in FIG.

This is an elastic-plastic restoring force characteristic, and is similar to that shown in FIG.

Also, one point g1 line curve in Figure 7! 155 is a history loop of restoring force characteristics due to vibration accompanied by friction, and is similar to that shown in FIG.

Next, the damping characteristics of the pipe support device 21 will be explained with reference to FIG. 8.

The damping characteristics of the piping support device 21, as shown by the solid line curve ti157, are the sum of the damping characteristics of the plate 27 shown by the broken line curve 59 and the damping characteristics due to vibration accompanied by frictional force shown by the dashed-dotted line curve 61. It is.

First, the damping characteristics of the plate 27.

Since the plate 27 has elastic-plastic restoring force characteristics as shown in FIG. 5, the plastic stiffness ratio γ is γ=0. Therefore, the relationship between the equivalent damping constant he and the plasticity rate μ (Q large response deformation (amplitude)/yield deformation) is as shown in FIG. That is, at the yield point, μ=1.0, and in the plastic region (μ>1.
0), the equivalent damping constant he increases parabolically as the plasticity modulus μ increases. For example, when the plasticity modulus μ is μ=2.0, the equivalent damping constant he is approximately 0.3. Therefore, the relationship between the equivalent attenuation constant he and the amplitude a is also a curve similar to the curve in FIG. 9, and this is represented by the broken line curve in FIG. It is 259. In the steel plate 27,
When a load in the elastic range (μ<1.0) is applied and the amplitude a is a small vibration, the equivalent damping constant he is about 0.01. On the other hand, when a large load in the plastic region is applied and the amplitude a is large, the equivalent damping constant he increases in proportion to the amplitude a.

Next, the damping characteristics due to vibration accompanied by frictional force R.

The energy consumption ΔW for one cycle due to the frictional force R is: ΔW=4Ra (1)
It is expressed as Generally, the steady amplitude y is set as y=acos(pt-θ)...(2>) (P: circular frequency, t: time, 01 phase difference), and the energy consumption during one cycle is made equal. When the equivalent viscous damping coefficient Ce is determined, ΔW=yrCePa2.

In addition, in general, the equivalent viscous damping constant Ce and the equivalent damping constant he
The relationship with is .

Therefore, from equations (1), (3), and (4), the equivalent damping constant he due to vibration accompanied by the frictional force R is the natural circular frequency of the system. From this equation (5), the equivalent damping constant he due to vibration accompanied by the frictional force R and the amplitude a are inversely proportional to each other, and this relationship is shown by the dashed-dotted curve 61 in the m8 diagram.

Therefore, the damping characteristics of plate 27 and a! According to the damping characteristic of the piping support device 21, which is a combination of the damping characteristic due to vibration accompanied by the frictional force R, when a small load within the elastic range of the plate 27 acts between the fixed rod 23 and the support rod 25, The small amplitude vibration caused by the small load is mainly 19F! A is attenuated by force R. Further, when a large load within the plastic region of the plate 27 acts between the fixed rod 23 and the support rod 25, the large amplitude vibration caused by the large load is damped mainly by the plastic strain energy of the plate 27. As a result, the piping support device 21 has improved G damping characteristics in the shaded area in FIG. 8, compared to the conventional piping support device using the plate 27 or the like.

According to the above example, when a large load in the plastic region of the plate 27 acts from the piping system and a large amplitude vibration occurs, this vibration is damped by the plastic strain energy of the plate 27, and the piping system When a small load within the elastic range of plays 1 to 27 acts and a small amplitude vibration occurs, this vibration is generated between the side surface of the flat portion 33 and the shim 45.j! ! ta
Since the vibration is attenuated by the force 1≧, it is possible to suitably attenuate vibrations in the piping system having amplitudes a over a wide range of sizes. As a result, the earthquake resistance and reliability of the plant including the piping system can be improved.

Further, even if a small load within the elastic range of the plate 27 is applied from the piping system, the small amplitude and high frequency vibrations that occur at this time can be suitably damped, so fatigue failure of the plate 27 can be prevented.

Furthermore, since the piping support Vt position 21 is composed of a fixed rod 23, a support rod 25, a plate 27, and a guide 29, the structure is simple, and quality control and maintenance management are facilitated. .

In particular, the plate 27 as an elastoplastic member is made of steel and will not deteriorate due to radiation like vibration-proof rubber or become radioactive like oil in an oil snubber, so the frequency of maintenance management can be reduced. It can also be applied to nuclear power plants, expanding the scope of use.

In the above embodiment, the guide 29 is fixed to the flat part 33 of the fixed rod 23 and the guide 29 is slidably provided to the flat part 37 of the support rod 25. The guide 29 may be fixed to the side using bolts 41 and nuts 43, and this guide 29 may be slidably in contact with the fixed rod 23 side.Furthermore, the guide 29 may be fixed to the fixed rod 23 and the support rod 25. It may also be provided to be slidable together via a shim 45.

〔Effect of the invention〕

As described above, according to the vibration damping device according to the present invention,
An elastic member and a friction force generating member are installed between a fixed member that is fixed to the stationary system and a support member that supports the movable system, and the vibrations of the movable system are damped by the plastic strain energy of the elastic-plastic member, and the system is further fixed. Since it is attenuated by the we force generated between the friction force generating member and at least one of the member and the support member, large amplitude vibrations that occur when a large load within the plastic region of the elastoplastic member is applied are also elastoplastic. Small-amplitude vibrations that occur when a small load is applied within the elastic range of the member can also be suitably damped, and vibration damping performance can be improved.

Furthermore, fatigue failure of the elastic-plastic member can also be prevented.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of a pipe support device as a vibration damping device according to the present invention, and FIG.
Figure 3 is a cross-sectional view along line ■-■ in Figure 1, Figure 4 is an enlarged view of part ■ in Figure 3, and Figure 5 is a hysteresis loop of the elastic-plastic restoring force characteristics of the plate. Figure 6 shows I!
A diagram showing the history loop of restoring force characteristics due to vibration accompanied by J friction force, Figure 7 is a diagram showing the history loop of restoring force characteristics in the pipe support device of Figure 1, and Figure 8 is a diagram showing the history loop of restoring force characteristics in the pipe support device of Figure 1. Figure 9 is a diagram showing the relationship between the equivalent damping constant he of the plate and the plasticity modulus μ, and Figures 10 and 11 are diagrams showing the damping characteristics of the device. 12 is a plan view showing the plate of FIG. 11, respectively. 21... Vibration damping device, 23... Fixed rod, 25
. . . Support rod, 27 . . . Plate, 29 . . . Guide, 45 . Figure 1 Figure 2 Plastic A Prison μ Figure 9 Figure 8 Figure 10 Figure 11 Figure 12

Claims (1)

[Scope of Claims] 1. A fixed member fixed to the stationary system, a supporting member supporting the movable system, and an elastic member installed between the fixed member and the supporting member to damp vibrations of the movable system by plastic strain energy. It is characterized by comprising a plastic member and a frictional force generating member attached between the fixed member and the supporting member and damping vibrations of the movable system by the frictional force generated between at least one of these two members. Vibration damping device. 2. The vibration damping device according to claim 1, wherein the frictional force generating member is fixed to the fixed member and is provided in slidable contact with the supporting member. 3. The vibration damping device according to claim 1 or 2, wherein the movable system is a piping system.