JPH03260245A - Soundproof floor structure - Google Patents

Abstract

PURPOSE:To prevent shock sounds, by attaching dynamic dampers to the ceiling slab in a building having a plurality of stories at least two antinodes of inherent oscillation mode of the slab and by tuning them to the inherent value of the slab. CONSTITUTION:Dynamic dampers 3, 4 are attached to the ceiling slab 1 of a building body having a plurality of stories in the vicinities of at least two inherent antinodes of the oscillation mode out of primary, secondary,..., n-order oscillation modes of the slab. And it is set that the inherent value of dynamic damper/inherent value of slab = 0.9-1.4, total weight/slab weight = 0.02-0.5, and loss coefficient = 0.02-0.4. And the inherent value of the dynamic damper is tuned to be near that of the slab. In this way, shock sounds of the floor generated on the upper stories can be effectively prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a soundproof floor structure using a dynamic damper to prevent floor impact noise generated on floors.

[Conventional technology]

Conventionally, when installing a dynamic damper on a slab,
The optimal number of installations and the setting of eigenvalues have been determined through field verification. For example, as shown in FIG. 10, six dynamic dampers 100 were also installed at node 2 (indicated by a dotted line in the drawing) of the vibration mode at the fourth-order eigenvalue (55 Hz) of slab 1.

The part surrounded by the dotted line on the drawing indicating node 2 of the vibration mode is the antinode part of the vibration mode.There are 6 antinodes in total, 3 rows in the X-axis direction and 2 rows in the Y-axis direction. 18 in the part
Ke's Dynamic Damper 101 was installed. Both dynamic damper 100 and 101 have their eigenvalues 5.
It was tuned to 8Hz.

[Issues to be resolved]

Conventionally, a dynamic damper 100 is also provided at the node 20 portion of the vibration mode, and the dynamic dampers 100, 101 are arranged so as to correspond only to a predetermined eigenvalue of the slab 1.
Because of this, it was not possible to effectively prevent the floor impact noise that occurs upstairs.

Therefore, this invention focuses on the fact that the eigenvalues of a slab are not constant and that providing a dynamic damper near the antinode of the vibration mode is effective in preventing floor impact noise. In addition, it is an object of the present invention to provide a soundproof floor structure that effectively prevents floor impact noise by considering the mounting position of a dynamic damper.

[Failure to solve the problem]

In order to achieve the above object, the present invention provides slab eigenvalues of the first order, second order, .
...A dynamic damper is installed near the antinode of the vibration mode of at least two eigenvalues of the nth order, respectively,
The dynamic damper's eigenvalue is tuned to be close to the slab's eigenvalue.

[Effect]

In this invention, for example, focusing on the third-order eigenvalue (38) (z) and the fourth-order eigenvalue (55 &) among the eigenvalues of the slab,
The eigenvalue is 40Hz at the antinode of the vibration mode of each eigenvalue,
By installing a dynamic damper tuned to 58&, it was possible to reduce slab vibration over a wide range of frequencies.

〔Example〕

Preferred embodiments of the present invention will be described below with reference to the drawings.

In the embodiment shown in FIG. 1, the cubic eigenvalue (38
A dynamic damper 3 (hatched in the figure) whose eigenvalue is tuned to 40Hz is installed at the antinode of the vibration mode of the slab 1 (55H).
A dynamic damper 4 with an eigenvalue tuned to 58& was installed at the antinode of the vibration mode of z). The dynamic dampers 3, 4 consist of an additional mass 5 and a spring material 6 (see FIG. 2.3). Figure 4 shows eight dynamic dampers 3 (40Hz) installed at the antinode of the vibration mode of the third-order eigenvalue (38Hz) of slab 1, and vibration is effective for the 103rd-order eigenvalue of the slab. to prevent. Figure 5 shows the fourth-order eigenvalue (55Hz) of slab 1.
Dynamic damper 4 (5
81 (z) is installed, and 4 of slab 1 is installed.
Vibration is effectively prevented for the following eigenvalues. The example shown in Fig. 1 is a combination of the installation examples of the dynamic dampers 3 and 4 shown in Fig. 4.5 to prevent vibrations against the 3rd and 4th order eigenvalues of the slab l. . It is most preferable to install the dynamic dampers 3 and 4 at the center of each antinode of the vibration mode, but even if the center positions are slightly shifted, the effect can be obtained if the dampers are installed within the range of the antinode.

The eigenvalues of slab I are not only 3rd and 4th order, but also Fig. 6 (
As shown in a), (company), (C), 1st, 2nd, 5th, and even 6th, 7th, etc. (not shown), n
The following eigenvalues exist. To measure the antinode and node 2 of the vibration mode of the eigenvalue, a mode analysis is performed. For example, two-channel FET (First F.

(Transformation) An acceleration sensor with a fixed measurement point is attached to one f+'J channel of the analyzer, and the measured value there is used as a reference to compare the value obtained from another acceleration sensor measured in another channel. By moving the measurement points on the slab 1, the amplitude ratio (transfer function) and phase of the vibration at each point can be determined. By organizing the data obtained from these results using a computer, the vibration mode at each resonance point of the slab 1 can be determined.

If the eigenvalue of the dynamic damper 3.4 is f (&), the mass of the additional mass 5 is M (kg>), the spring constant of the spring material 6 is K (kg/cm), and the loss coefficient is η, then it can be expressed by the following formula. If you want to tune the eigenvalue to a high frequency, you can do so by decreasing M or increasing K. If you want to tune to a low frequency, you can do so by increasing M or decreasing K. Adjustment of the eigenvalue of 3.4 can be easily performed.

In the mode analysis described above, dynamic damper 3
．． 4 is installed on the ceiling side of the slab 1, changes in vibration properties can be investigated using a simulation method. Optimization of the installation position, installation quantity, weight, damping coefficient, etc. of the dynamic damper 3.4 can be studied on paper, and design efficiency is significantly improved compared to conventional simulations based on field verification. As a result of performing such simulations, the following was found.

That is, the weight of slab 1 is M. , if the total weight of the dynamic damper 3.4 is Ml, then M,/MO=0.
It is desirable to set it to 02-0.5. If it is larger than 0.5, it will be difficult to reduce vibration at the intended frequency.

Also, the eigenvalue of slab 1 is f. , if the eigenvalue of the dynamic damper 3.4 is f+, then r+/fo=0.9~
1.4 (see Figure 7). If it deviates from this range, the vibration reduction effect will be diminished. The curve displayed as "unmeasured" in FIG. 7 shows the resonance curve of the slab 1 alone without the dynamic damper installed. The vibrating object (slab 1) has many resonant systems in a wide frequency range, each of which can be thought of as a system with independent mass, spring, and resistance, and when the frequency is changed, resonance occurs as shown in Figure 7. Draw a curve. Further, the vibration acceleration transmission rate H in FIG. 7 is χ0. Furthermore, the loss coefficient η of the dynamic damper 3.4 is desirably set to 0.02 to 0.4, as shown in FIG. This loss coefficient η is a frequency width Δf (vibration energy is 1/2
It is defined as the ratio of the frequency width), and is determined from the formula: η=Δf/f. When rubber is used as the spring material 6 of the dynamic damper 34, the loss coefficient η is as follows: Natural rubber ・・・・・・・・・・・・ 0.05
~0.15 Chloroprene rubber ・・・・・・ 0,1
5～0,3SBR・・・・・・・・・・・・ 0.15
~0.3 Butyl rubber ・・・・・・・・・・・・
The loss coefficient η can be changed from 0.25 to 0.4 by changing the material of the rubber used for the spring material 6.

The “unmeasured” curve in the graph is for slab 1, which is the same as in Figure 7.
A single resonance curve is shown.

In addition, in the graph showing the change in transfer function due to tuning frequency change and the effect of the dynamic damper shown in Fig. 7, M = 10 kg for the dynamic damper.
, η=0.1.

Furthermore, in the graph shown in FIG. 8, M=10 kg.

f l/fo = 1.05.

Figure 9 shows the JIS-A-1 floor impact sound isolation performance.
This is a graph measured based on 418, and ■ to ■ in the figure are as follows. A heavy floor impact source using a bang machine was used as the floor impact source.

■ ... Performance of the slab material ■ ... Conventional example shown in Fig. 10 ■ ... Shown in Fig. 2 ■ ... Example shown in Fig. 1 As is clear from this graph, this In invention, the symbol ■
, Improvement in floor impact sound insulation performance was observed compared to those shown in ■.

〔effect〕

As explained above, according to the present invention, the eigenvalues of the slab, 1st order, 2nd order, .
...A dynamic damper is installed near the antinode of the vibration mode of at least two eigenvalues of the nth order, respectively,
Since the eigenvalue of the dynamic damper is tuned to be close to the eigenvalue of the slab, floor impact noise generated on floors can be effectively prevented.

[Brief explanation of drawings]

Fig. 1 is a plan view showing a preferred embodiment of the present invention, Fig. 2 is a floor plan of the dynamic damper, Fig. 3 is a view from below Fig. 2, and Fig. 4 is a tertiary fixed value. 5th plan view showing a dynamic damper installed at the antinode of the vibration mode of
The figure is a plan view of a dynamic damper installed at the antinode of the fourth-order fixed value vibration mode, and Figures 6 (a) to (C) are diagrams showing the first, second, and fifth orders of the fixed value of the slab. , Figure 7 is a graph showing the change in the transfer function due to a change in the tuning frequency and the effect of the dynamic damper, Figure 8 is a graph showing the change in the transfer function due to a change in the loss coefficient and the effect of the dynamic damper, and Figure 9 is a graph showing the effect of the dynamic damper on the floor impact. A graph showing the measurement results of sound insulation performance, and FIG. 10 is a plan view showing a conventional example. 1-... Slab, 2... Vibration mode node, 3.4... Dynamic damper 5... Additional mass, 6... Spring material.

Claims (1)

[Claims] 1. Near the position of the antinode of the vibration mode of at least two eigenvalues of the first, second, ... n-th eigenvalues of the slab on the ceiling side of the slab of a multi-story building structure. A soundproof floor structure characterized by installing a dynamic damper in each of the slabs and tuning the eigenvalue of the dynamic damper to be close to the eigenvalue of the slab. 2. Eigenvalue of dynamic damper/Eigenvalue of slab =
The soundproof floor structure according to claim 1, characterized in that the soundproof floor structure has a coefficient of 0.9 to 1.4. 3. Total weight of dynamic damper/slab weight = 0.
02 to 0.5.
Soundproof floor structure described in . 4. Set the loss coefficient of the dynamic damper to 0.02 to 0.
The soundproof floor structure according to any one of claims 1 to 3, characterized in that the soundproof floor structure is set in a range of 4.