JP7210393B2 - Design support method and design support device for soundproof building - Google Patents

Description

In the design stage of a soundproof building, the present invention uses vibrations based on the dynamic characteristics of the vibration generator and actual measurements of the sound generated by the vibration to predict the sound that propagates from the vibration generator to the surroundings. The present invention relates to a soundproof building design support method and design support device that contributes to accurate soundproof building design by using predicted sound as a design element of a soundproof building.

For example, Patent Documents 1 to 3 are known as techniques related to soundproof facilities having soundproof performance. The "low-frequency sound reduction device" of Patent Document 1 is provided with a Helmholtz resonator known to absorb sound of a specific frequency, and uses a thin panel that enables efficient sound absorption. Low-frequency sound reduction An object of the present invention is to provide a low-frequency sound reduction device that encloses a sound source with a panel. The resonance frequency of the resonator is set to a value substantially matching the low frequency vibration of the sound source and is configured to absorb low frequency sound from the sound source.

Patent document 2, "Infrasound transmission reduction method and infrasound transmission reduction device", is an infrasound transmission reduction that suppresses leakage of infrasound from an opening of an infrasound insulation house that is always open. An ultra-low frequency soundproof house covering an ultrasonic sound source and an ultra-low frequency reactance provided at an opening of the ultra-low frequency soundproof house that is always open. An infrasound transmission reduction method and an infrasound transmission reduction device for reducing infrasound radiated to the outside from an opening, comprising a reactance type silencer for infrasound has an inlet and an outlet with a wetting edge length of a predetermined length proportional to the apparent resistance component of the acoustic impedance, and develops an acoustic boundary layer in proportion to the wetting edge length to reduce the apparent resistance component and configured to reduce infrasound by converting acoustic energy into thermal energy.

Patent Document 3, "Infrasound reduction device and soundproof house equipped with the infrasound reduction device" provides a device for effectively reducing infrasound and a soundproof house equipped with the device. An infrasound reduction device provided in an opening of a soundproof house covering a sound source that emits infrasound, wherein the infrasound reduction device extends along the edge of the opening It is provided so as to protrude inside the soundproof house, has a cylindrical shape, and is configured to be integrally provided with the soundproof house.

JP-A-2001-75574 JP 2009-282155 A JP 2011-221073 A

In general, a vibrating machine that vibrates during operation generates noise along with the vibration. In order to prevent the noise from harming the surrounding environment, the vibration machine is surrounded by a soundproof building such as a soundproof house to prevent the noise from propagating to the surroundings.

When vibration characteristics in three-dimensional space have directivity, such as when the amplitude of vibration generated by a vibrating machine is particularly large in a specific direction, and the vibration is periodic, the noise accompanying the vibration has directivity. Therefore, the direction in which sound with high sound pressure propagates differs from the direction in which sound with relatively low sound pressure propagates, and the directional characteristics of the noise are not uniform.

When it is necessary to provide a normally open opening, such as an opening for equipment, in a soundproof building, if the opening is formed in the direction in which sound with a large sound pressure propagates, the vibration generating machine is covered with the soundproof building. However, the soundproofing effect is significantly impaired.

In the past, the soundproofing effect of the soundproof building could not be confirmed until after the soundproof building was built and the vibration generating machine was installed inside. If a sufficient soundproof effect is not obtained, the soundproof building must be repaired or refurbished, and this work requires a great deal of time and effort.

At the stage of designing a soundproof building, if it were possible to predict the dynamic characteristics of the vibrating machine, specifically the propagation of noise generated by directional periodic vibrations, it would be possible to predict the propagation of large sound pressure. Since it is possible to form an opening while avoiding the direction in which it is formed, it has been desired to devise a method and apparatus that enable such prediction at the design stage.

The present invention was devised in view of the above-mentioned conventional problems. It is possible to predict the sound that propagates from the vibration machine to the surroundings, and by using the predicted sound as a design element of the soundproof building, a soundproof building design support method and design that contributes to the accurate design of the soundproof building. The purpose is to provide a support device.

A soundproof building design support method according to the present invention is a method for supporting the design of a soundproof building that encloses a vibration machine that generates sound in conjunction with directional periodic vibrations. Using a sound pressure measuring instrument provided nearby, the sound pressure emitted from the vibration machine due to vibration was actually measured for each coordinate plane of a three-dimensional orthogonal coordinate system, and provided to the vibration machine. Using a vibration acceleration measuring instrument, the vibration acceleration of the vibrating machine is actually measured for each coordinate plane of a three-dimensional orthogonal coordinate system, and a calculation device is used to measure the sound pressure and vibration acceleration using the time domain finite difference method. Arithmetic processing is performed, and a predicted sound pressure value predicted to propagate from the position of the vibration generating machine as a starting point to a coordinate position in a three-dimensional space over time is obtained as a design element of the soundproof building. and

The predicted sound pressure value is an arithmetic mean value of instantaneous predicted sound pressure values predicted for each instant.

A predicted sound pressure distribution in a three-dimensional space that spreads around the vibration machine is obtained using the predicted sound pressure value through arithmetic processing of the arithmetic unit.

The sound pressure and the vibration acceleration are actually measured at the same timing.

A soundproof building design support device according to the present invention is a device that supports the design of a soundproof building that encloses a vibration machine that generates sound in conjunction with directional periodic vibration. a sound pressure measuring device provided in the vicinity of the vibration excitation machine for actually measuring sound pressure emitted from the vibration excitation machine due to vibration on each coordinate plane of a three-dimensional orthogonal coordinate system; A vibration acceleration measuring device that actually measures the vibration acceleration of a vibrating machine on each coordinate plane of a three-dimensional orthogonal coordinate system, and the actual values of the sound pressure and vibration acceleration measured by the sound pressure measuring device and the vibration acceleration measuring device. A computing device that performs computational processing by the time-domain finite difference method using the above-mentioned soundproof building, and obtains, as a design element of the above-mentioned soundproof building, a predicted sound pressure value that is predicted to propagate in a three-dimensional space over time starting from the vibration-exciting machine. and

In the soundproof building design support method and design support device according to the present invention, at the stage of designing a soundproof building, the vibration based on the dynamic characteristics of the vibration machine and the actual measurement value of the sound generated by the vibration are used. , the sound propagating from the vibration machine to the surroundings can be predicted, and the predicted sound can be used as a design element of the soundproof building, which can be used for the accurate design of the soundproof building.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram for explaining a preferred embodiment of a design support device used in a soundproof building design support method according to the present invention; FIG. 3 is a graph diagram illustrating an example of actually measuring the sound pressure of a vibrating sieve machine in a three-dimensional space using a sound pressure measuring instrument that constitutes the design support device for a soundproof building shown in FIG. 1 ; 2 is a graph illustrating an example of actual measurement of vibration acceleration of a vibrating sieve on each coordinate plane of a three-dimensional orthogonal coordinate system using a vibration acceleration measuring device that constitutes the soundproof building design support device shown in FIG. 1. FIG. Using the arithmetic unit that constitutes the design support system for the soundproof building shown in Figure 1, the sound pressure and particle velocity that indicate the state of the sound field in the space (analysis area) around the vibrating sieve machine are calculated as the predicted sound pressure values. FIG. 10 is an explanatory diagram for explaining a calculated state; FIG. 5 is an explanatory diagram including FIG. 4 and showing an analysis region extending around the vibrating sieve machine together with calculation points; FIG. 4 is a contour diagram illustrating a state in which a predicted sound pressure distribution at a certain moment in a three-dimensional space extending around the vibrating sieve machine, which is an analysis area, is acquired using predicted sound pressure values obtained by arithmetic processing of the arithmetic unit. FIG. 7 is a contour diagram illustrating a state in which an average predicted sound pressure distribution obtained by accumulating and averaging instantaneous predicted sound pressure distributions of which an example is shown in FIG. 6 over time is acquired.

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of a soundproof building design support method and design support device according to the present invention will be described in detail below with reference to the accompanying drawings.

A vibrating sieve machine is known as an example of a vibrating machine that produces directional periodic vibrations. A vibrating sieve machine is used, for example, to separate surplus soil and muddy water from muddy water generated in shield tunneling construction, continuous wall construction, foundation piling construction, dams, harbors, and the like.

As shown in FIG. 1, the vibrating sieve machine 1 is provided with a rotating drum 4 on which a rotating shaft (not shown) is eccentrically mounted so as to come into contact with the top of a tank 3 supported on a spring 2. The sieving action is obtained by displacing the tank 3 in the vertical direction by the eccentric rotation of the .

Then, from a sludge drain pipe 6 extending to the upper side of the separation screen 5 which is a "sieve surface" installed in the tank 3, sludge drain water 7 containing earth and sand and gravel is thrown in toward the screen 5, and the screen 5 The sediment and gravel 8 received and separated by the tank 3 are transferred to a belt conveyor from a discharge duct 9 attached to the tank 3 and carried out, and the muddy water 10 passing through the screen 5 is discharged to a drainage system.

The vibrating sieve machine 1 vibrates the air due to the movement of the tank 3, so that it generates ultra-low frequency (about 1 to 20 Hz) noise, which propagates to the surroundings.

The ultra-low frequency sound generated from the vibrating screen machine 1 has directivity due to the dynamic characteristics due to the eccentric rotation of the rotary drum 4, but the dynamic characteristics of the vibrating screen machine 1 itself and the transmitted ultra-low frequency sound Relationships are not easily grasped.

When the vibrating sieve machine 1 is surrounded by a soundproof building because the sieved earth and sand and gravel 8 are carried out by a belt conveyor, the soundproof building must have an opening that is normally open while the vibrating sieve machine 1 is in operation. It is desirable to install the opening in a position where sound with relatively low sound pressure propagates, avoiding the direction in which sound with high sound pressure propagates, based on the directivity of ultra-low frequency sound. .

In this embodiment, using the sound pressure and vibration acceleration measured for the vibrating sieve machine 1, the well-known finite difference time domain method (FDTD method) is used to determine the propagation state of sound, specifically, ultra-low frequency sound We are trying to predict the temporal change of the sound pressure distribution of the system at the preliminary design stage.

First, for example, at a manufacturing factory of the vibrating screen machine 1, the vibration of the vibrating screen machine 1 and the sound emitted from the vibrating screen machine 1 accompanying the vibration are measured.

A vibration acceleration detector 11 for measuring the vibration acceleration of the vibrating screen machine 1 every moment is installed in the vibrating screen machine 1 (tank 3).

The vibration acceleration measuring device 11 is of a three-axis measurement type, whereby vibration acceleration is measured over time on each of the coordinate planes XY, YZ, and XZ of the XYZ three-dimensional orthogonal coordinate system.

A sound pressure measuring instrument 13 for measuring the sound pressure emitted from the vibrating screen machine 1 generating vibrations is placed in the vicinity of the vibrating screen machine 1 using a temporary frame 12 or the like surrounding the vibrating screen machine 1. to be arranged.

Specifically, a sound pressure measuring device 13 is provided so as to face the front surface, rear surface, left and right side surfaces, and top surface of the vibrating screen machine 1, thereby measuring each coordinate of the XYZ three-dimensional orthogonal coordinate system. Sound pressure can be measured over time for planes XY, YZ, and XZ.

In the illustrated example, four sound pressure measuring instruments 13 are arranged on the front surface and rear surface, and six on each of the left and right side surfaces and the upper surface. Any number may be provided. For a plurality of surfaces, an arithmetic mean value of sound pressures actually measured by the sound pressure measuring device 13 is used. Moreover, in the actual measurement, it is preferable to install an additional sound pressure measuring device for reference at a position appropriately separated from the vibrating screen machine 1 and perform the measurement.

2 and 3 show examples of actually measuring the vibration acceleration and sound pressure of the vibrating screen machine 1. FIG. The sound pressure and the vibration acceleration were measured at the same timing, and the sampling frequency was set to 44, 100 Hz for both the sound pressure measuring device 13 and the vibration acceleration measuring device 11 .

FIG. 2 is a graph showing sound pressure frequency characteristics near each surface. The frequency characteristics of all surfaces were substantially the same at about 80 Hz or less, and a very large sound pressure sound was generated near 16 Hz (=980 rpm/60 seconds) due to the rotational speed of the rotary drum 4 .

FIG. 3 shows changes in the vibration acceleration of the vibrating screener 1 on each coordinate plane (YZ plane, XZ plane, XY plane) of the three-dimensional orthogonal coordinate system from moment to moment. Following the movement of the rotating drum 4 rotating eccentrically, the vibrating screen machine 1 (tank 3) also repeatedly moved eccentrically.

The vibration acceleration in the vertical direction (Z direction) is greater than that in the horizontal direction (XY direction), and the vibration acceleration in the longitudinal direction (Y direction) is greater than that in the horizontal direction (X direction). It was found that the directional vibration occurred periodically as shown in the figure.

In this example, the ultra-low frequency sound (noise) generated by the vibrating sieve machine 1 was generated by vibrating the air in the tank 3, and the frequency was about 16 Hz.

Next, based on the actually measured sound pressure and vibration acceleration from the vibrating sieve machine 1, sound is predicted by arithmetic processing of the arithmetic unit 14 (see FIG. 1). The arithmetic unit 14 has a wireless function for wirelessly obtaining measured values from the sound pressure measuring device 13 and the vibration acceleration measuring device 11, and is connected to input means such as a keyboard and output means such as a monitor to perform arithmetic processing. It consists of a personal computer or the like that outputs results from input data.

The arithmetic device 14 uses the values of the sound pressure and the vibration acceleration actually measured by the sound pressure measuring device 13 and the vibration acceleration measuring device 11 from time to time. Calculates and outputs the sound field that

In the present embodiment, the FDTD method differentiates the Helmholtz wave equation using actually measured sound pressure and vibration acceleration as initial conditions, and calculates the sound field The sound pressure and particle velocity (see FIG. 4) indicating the state are calculated as predicted values of the sound pressure. The computing device 14 calculates the predicted value every moment.

FIG. 4 shows an analysis area D on an XY coordinate plane (where X and Y are positive values) with the vibrating screen machine 1 as a starting point, that is, as a coordinate origin. In the illustrated example, FIG. 4A shows that the sound pressure and particle velocity at time t=n of the sound emitted from the vibrating sieve machine 1 at the calculation point k (coordinate position) correspond to the "color shading" at the calculation point. ” and “Vector”.

These displays are graphical representations of predicted sound pressure values (calculated values) that are predicted to propagate to coordinate positions in a three-dimensional space over time.

FIG. 4(B) shows the sound pressure and particle velocity at time t=n+1, from which it can be understood how sound propagates due to vibration.

FIG. 4(C) further shows the sound pressure and particle velocity at time t=n+2, from which it can be understood how the sound accompanying the vibration propagates further.

By comparing FIG. 4B and FIG. 4C, it can be seen that the sound at calculation point kP at time t=n+1 transitions to calculation points kQ and kR at time t=n+2.

FIG. 4 is an enlarged view of the main part of the analysis area D, and FIG. 5 shows the analysis area D extending around the vibrating sieve machine 1, including FIG.

FIG. 4 is a representation for the analysis domain of the coordinate planes with positive X and Y values, the coordinate plane with positive X and negative Y values, the coordinate plane with negative X and positive Y values, and the coordinate plane with positive X and Y values. , and Y can be similarly expressed in the coordinate planes with negative values, and these analysis areas express the propagation of sound in the XY plane around the vibrating screen machine 1 .

Similarly, the analysis regions of the XZ coordinate plane and the YZ coordinate plane can also be expressed, and it is predicted that the three-dimensional space around the vibrating screen machine 1 will propagate to each coordinate position (calculation point k). Predicted sound pressure values (calculated values themselves) and graphical representations are obtained and used as design elements for the soundproof building.

FIG. 6 shows the sound pressure distribution at an instant when there is a sound field in the entire analysis area D (XY coordinate plane) using the predicted sound pressure values obtained by the arithmetic processing of the arithmetic unit 14. An instantaneous predicted sound pressure distribution in dimensional space is shown.

In the drawing, it can be understood that the sound pressure in the lower left direction of the vibrating screen machine 1 is large (the density of the displayed color is high). Similar instantaneous predicted sound pressure distributions can be obtained for the XZ coordinate plane and the YZ coordinate plane.

FIG. 7 shows a predicted sound pressure distribution (average predicted sound pressure distribution) on the XY coordinate plane using the arithmetic average value in a predetermined period of the instantaneous predicted sound pressure value (instantaneous predicted sound pressure value) at each calculation point k. , that is, the predicted sound pressure distribution is expressed by the cumulative arithmetic mean value of the instantaneous predicted sound pressure distribution shown in FIG.

Similar average predicted sound pressure distributions can be obtained for the XZ coordinate plane and the YZ coordinate plane.

From the dynamic characteristics of the vibrating screen machine 1, in the drawing, a large sound pressure range can be seen from the diagonally upper right direction of the vibrating screen machine 1 to the clockwise left direction. Since a range where the sound pressure is small can be seen in the diagonally upper left direction, it can be seen that it is preferable to form the opening 16 of the soundproof building so as to match this range.

As described above, according to the design support method and the design support device for a soundproof building according to the present embodiment, the sound pressure measuring device 13 provided near the vibrating screen machine 1 is used to measure vibration from the vibrating screen machine 1. The sound pressure emitted as a result is actually measured for each coordinate plane of a three-dimensional orthogonal coordinate system, and the vibration acceleration of the vibrating screen machine 1 is measured using the vibration acceleration measuring device 11 provided in the vibrating screen machine 1 in three dimensions. Each coordinate plane of the orthogonal coordinate system is actually measured, and arithmetic processing is performed by the arithmetic unit 14 by the time domain finite difference method using the measured values of the sound pressure and vibration acceleration. A predicted sound pressure value that is predicted to propagate to the coordinate position in the dimensional space is acquired as a design element of the soundproof building. And using the actual measurement value of the sound generated by the vibration, the sound propagating from the vibrating screen machine 1 to the surroundings can be predicted in a three-dimensional space, and the predicted sound can be used as a design element of the soundproof building. It can be used for accurate soundproof building design.

1 vibrating sieve machine 11 vibration acceleration measuring device 13 sound pressure measuring device 14 computing device

Claims (5)

A method for assisting the design of a soundproof building surrounding a vibrating machine that produces sound in conjunction with directional periodic vibration, comprising:
Using a sound pressure measuring instrument provided near the vibration excitation machine, the sound pressure emitted from the vibration excitation machine due to vibration is actually measured on each coordinate plane of a three-dimensional orthogonal coordinate system,
Using a vibration acceleration measuring device provided in the vibration machine, the vibration acceleration of the vibration machine is actually measured on each coordinate plane of a three-dimensional orthogonal coordinate system,
An arithmetic unit performs arithmetic processing by the time domain finite difference method using the measured values of the sound pressure and vibration acceleration, and predicts that the position of the vibration generating machine is the starting point and propagates to the coordinate position in the three-dimensional space as time passes. A design support method for a soundproof building, characterized in that a predicted sound pressure value to be estimated is acquired as a design element of the soundproof building. 2. The soundproof building design support method according to claim 1, wherein the predicted sound pressure value is an arithmetic mean value of instantaneous predicted sound pressure values predicted at each instant. 3. The soundproofing according to claim 1 or 2, wherein a predicted sound pressure distribution in a three-dimensional space spreading around the vibration generating machine is obtained using the predicted sound pressure value through arithmetic processing of the arithmetic unit. A building design support method. The soundproof building design support method according to any one of claims 1 to 3, wherein the actual measurement of the sound pressure and the vibration acceleration are performed so that measurement timings match. A device that supports the design of a soundproof building that encloses a vibrating machine that generates sound with directional periodic vibration,
a sound pressure measuring instrument provided in the vicinity of the vibration excitation machine for actually measuring sound pressure emitted from the vibration excitation machine due to vibration on each coordinate plane of a three-dimensional orthogonal coordinate system;
a vibration acceleration measuring device provided in the vibration excitation machine for actually measuring the vibration acceleration of the vibration excitation machine on each coordinate plane of a three-dimensional orthogonal coordinate system;
Using the sound pressure and vibration acceleration actually measured by the sound pressure measuring instrument and the vibration acceleration measuring instrument, arithmetic processing is performed by the time domain finite difference method, and it propagates to the three-dimensional space according to the passage of time starting from the vibration machine. A soundproof building design support device, comprising: an arithmetic device for obtaining a predicted sound pressure value predicted as the building progresses, as a design element of the soundproof building.

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