JP7169721B2 - Propagated sound prediction method and propagated sound prediction device - Google Patents

Description

The present invention relates to technology for predicting transmitted sound associated with structures such as buildings.

2. Description of the Related Art As a technique for predicting transmitted sound related to a structure such as a building, for example, Patent Document 1 discloses a technique for predicting noise propagating in the air using an "extended energy integral equation method."

JP 2003-75244 A

However, noise originating from noise/vibration sources also includes airborne sound that propagates through structures and radiates at the sound receiving position. On the other hand, the technique described in Patent Document 1 is a technique for predicting noise only for airborne sound. Therefore, it is difficult to predict the noise level at the sound receiving position taking into account the solid-borne sound propagating through the structure.

Therefore, the present invention has been made by paying attention to such problems, and provides a method for predicting the noise level at the sound receiving position, taking into consideration the solid-borne sound propagating in the structure. An object of the present invention is to provide a prediction method and a propagated sound prediction device.

In order to solve the above problems, a transmitted sound prediction method according to an aspect of the present invention includes the steps of: modeling a structure into a plurality of member elements to which vibration physical properties are assigned; calculating the acoustic radiation energy of the structure model by a statistical energy analysis method based on the incident vibration energy to and the vibration energy transmissibility between the member elements; converting into incident sound energy of structure-borne sound; and predicting a noise level at a sound receiving position by a boundary energy integration method based on the incident sound energy of structure-borne sound. .

Further, a transmitted sound prediction apparatus according to an aspect of the present invention includes the steps of: modeling a structure into a plurality of member elements to which vibration physical properties are assigned; calculating the acoustic radiation energy of the structure model by a statistical energy analysis method based on the vibration energy transmissibility between the member elements; a program comprising the step of converting into energy, and the step of predicting a noise level at a sound receiving position by a boundary energy integration method based on the incident acoustic energy of the solid-borne sound; a computer executing the program; characterized by comprising

According to the transmitted sound prediction method and apparatus according to an aspect of the present invention, it is possible to predict the noise level at the sound receiving position in consideration of the solid-borne sound propagating through the structure.

In order to solve the above problems, a transmitted sound prediction method according to another aspect of the present invention includes: a plurality of minute elements to which acoustic characteristics are imparted; a plurality of member elements to which vibration physical characteristics are imparted; and calculating the incident acoustic energy of airborne sound based on the incident acoustic energy from the noise/vibration source to the microelements and the acoustic energy transmissibility between the microelements. calculating the acoustic radiation energy of the structure model by a statistical energy analysis method based on the incident vibration energy from the noise/vibration source to the member elements and the vibration energy transmissibility between the member elements; converting acoustic radiation energy of the structure model into incident acoustic energy of structure-borne sound via coupling elements; and estimating the noise level at the sound receiving position by an energy integration method.

Further, a transmitted sound prediction apparatus according to another aspect of the present invention includes a step of modeling a structure using a plurality of minute elements to which acoustic properties are assigned and a plurality of member elements to which vibration physical properties are assigned. calculating the incident acoustic energy of the airborne sound based on the acoustic energy incident on the minute element from the noise/vibration source and the acoustic energy transmissibility between the minute elements; calculating the acoustic radiation energy of the structure model by a statistical energy analysis method based on the incident vibration energy to the member elements and the vibration energy transmissibility between the member elements; converting the energy into incident acoustic energy of structure-borne sound through a coupling element; and determining a sound receiving position by a boundary energy integration method based on the incident acoustic energy of the air-borne sound and the incident acoustic energy of the structure-borne sound. and a computer that executes the program.

According to the transmitted sound prediction method and apparatus according to another aspect of the present invention, the noise level at the sound receiving position can be predicted by taking into account the solid-borne sound propagating through the structure in addition to the air-borne sound. Therefore, air-borne sound and structure-borne sound can be predicted simultaneously.

According to the present invention, the noise level at the sound receiving position can be predicted in consideration of the solid-borne sound propagating through the structure.

It is a schematic diagram showing an example of a construction site where air-borne sound and solid-borne sound propagate simultaneously, and (a) is a schematic diagram of the entire construction site, and (b) is indicated by symbol R in (a). It is an enlarged view of the living room portion. FIG. 2 is a block diagram of propagated sound prediction processing executed by an embodiment of a propagated sound prediction device used in a method of predicting a propagated sound according to an aspect of the present invention; 3 is a diagram for explaining a structure model used in the transmitted sound prediction process of FIG. 2; FIG. 2, in which vibration elements (acoustic radiation energy of member elements of a structure model) are converted into acoustic elements (incident acoustic energy of solid-borne sound) via coupling elements. It is a figure which shows the image which is. FIG. 4 is a conceptual diagram showing parameters in simultaneous equations by the boundary energy integration method; It is a figure explaining handling of diffraction concerning one embodiment of the present invention.

An embodiment of the present invention will be described below with appropriate reference to the drawings. Note that the drawings are schematic. Therefore, it should be noted that the relationship, ratio, etc. between the thickness and the planar dimensions are different from the actual ones, and the drawings include portions where the relationship and ratio of the dimensions are different from each other.
Further, the embodiments shown below are examples of devices and methods for embodying the technical idea of the present invention. etc. are not specified in the following embodiments.

FIG. 1 shows an example of the demolition work of a building, and the figure is a conceptual diagram of demolishing the upper part of the building B with various construction machines M while a person P is staying in the living room R in the lower part of the building B. .
Here, in the demolition work, vibration propagates within the structure of building B, which is a structure (hereinafter also referred to as "solid-borne sound Ss"), and noise propagates as sound waves in the air (hereinafter referred to as "air Also referred to as “propagated sound As”). Therefore, in the living room R in the lower part of the building B, noise is generated by the structure-borne sound Ss and the air-borne sound As from noise/vibration sources such as the construction machine M.

On the other hand, the transmitted sound prediction apparatus of the present embodiment uses an extended energy integral equation method (boundary energy integration method) to predict all noise propagation related to a structure B such as a building. , a vibration propagation prediction method based on a statistical energy analysis method (hereinafter also referred to as SEA (Statisfical Energy Analysys)), and a “coupling element” (step S17 in FIG. 2) is created, whereby the solid-borne sound and Simultaneously analyze and predict the airborne sound by computer simulation.

Specifically, in FIG. 1, the construction machine M is the noise/vibration source, and the building B is divided into mesh-like minute elements to which acoustic characteristics are imparted, and a plurality of member elements to which vibration physical characteristics are imparted. It is a structure modeled as
Physical characteristics (sound absorption coefficient, transmission loss) related to acoustics are given as data to each minute element according to the part of the structure B. FIG. Also, the noise/vibration source M is given physical characteristics. The diffuse reflection coefficient is set to 1 for all elements so that all reflected energy is diffusely reflected.

Next, a method of obtaining noise propagation prediction according to the present embodiment will be described with reference to the block diagram of propagation sound prediction processing shown in FIG.
When the computer executes the propagated sound prediction processing program, as shown in the figure, first, in step S1, a prediction range for predicting the propagated noise is set. In step S2, the positions and number of noise/vibration sources M are set.

Further, in step S3, a model is constructed by dividing the members involved in sound reflection, sound absorption, and transmission in the structure B into member elements. As shown in an example of modeling in FIG. 3, of the structure B modeled as a plurality of member elements, reference numeral 1 is a slab, reference numeral 2 is a beam, and reference numeral 3 is a column, each of which is a "member element". corresponds to In addition, the predicted range of sound reception is set to the above-described room R on the second floor as the sound reception position.

Subsequently, as shown in FIG. 2, in step S4, acoustic physical characteristics such as the power level and directional characteristics of the noise/vibration source M are set. In step S5, according to each member element such as the slab 1, the beam 2, and the column 3, acoustic physical property coefficients such as sound absorption coefficient, sound transmission loss, and diffuse reflection coefficient are set, and in step S6, each member element is cut into a mesh and divided into multiple small elements. In step S7, coefficients of physical vibration characteristics such as density, Young's modulus, moment of inertia of area, and radiation efficiency are set for each member element.

Then, in step S8, the acoustic energy transmissibility from each minute element to each sound receiving position within the prediction range is calculated. In step S9, the acoustic incident energy that is incident on each minute element directly from the noise/vibration source M and via multiple diffraction is calculated.
Also, in step S10, the acoustic energy transmissibility between each minute element is calculated in consideration of reflection, multiple diffraction, and acoustic transmission. Acoustic energy transmissibility is a ratio of energy incident on an element to energy incident on another element, and is determined by distance attenuation, diffraction attenuation, transmission attenuation, and incident angle.

In step S11, the vibration energy transmissibility between each member element such as the slab 1, the beam 2, the column 3, etc. shown in FIG. 3 is calculated. In step S12, the incident vibration energy from the noise/vibration source M to the member element is calculated.
Then, in step S13, simultaneous equations are constructed with the vibration energy of each member element as unknowns, and in subsequent step S14, the simultaneous equations are solved by a statistical energy analysis method (hereinafter also referred to as SEA (Statistical Energy Analysis)). Then, in step S15, vibration energy is calculated for each member element.

Furthermore, in step S16, the acoustic radiation energy of each member element is calculated. Note that SEA is based on a known method (for example, Journal of the Acoustical Society of Japan, Vol. 48, No. 6 (1992)), so a detailed explanation is omitted.
In step S17, as illustrated in FIG. 4, vibration energy (vibration element) possessed by the member element is converted into incident acoustic energy (acoustic element) of solid-borne sound via the coupling element. A coupling parameter C of the coupling element is calculated from the physical property values of the vibration surface by the following (Equation 1). where _ρ0 is the density of air, _c0 is the speed of sound in air, and σ, ρ, E, and h are the radiation efficiency, density, Young's modulus, and thickness of the surface material that radiates sound, respectively.

Here, the process of deriving the above "connection element" will be described.
Now, the impedance Z of bending vibration in an infinite plate can be obtained by the following (Equation 2) from literature (Sound Insulation Design Data for Buildings, Architectural Institute of Japan, P124). In (Formula 2), B is bending stiffness, E is Young's modulus, ρ is density, and h is thickness of the plate.

In the vibrating element of FIG. 4, if the average velocity of the plate bending vibration is _v , the vibration energy IV per unit area of the plate bending vibration (vibration that generates sound) of the vibrating element is given by the following formula from the statistical energy theory: 3) can be approximated. As a result, the following (Equation 4) is obtained.

I _V =Zv ² (equation 3)

On the other hand, in the bending vibration of the plate, if the intensity of the radiated sound in the vibrating element at the average velocity v is I _S , the density of air is ρ ₀ , the speed of sound is c ₀ , and the radiation efficiency is σ, the following equation (5) can be obtained. becomes.
I _S =ρ ₀ c ₀ v ² σ (equation 5)

Therefore, by eliminating v2 from (Equation ⁴ ) and (Equation 5), the following (Equation 6) for calculating the radiated sound intensity from the vibration energy, that is, the "acoustic radiation energy of the acoustic element" is can get.

Therefore, if C is a coefficient for converting the "vibration energy I _V of the vibration element" into the "acoustic radiation energy I _S of the acoustic element", the above (Equation 1) is obtained.

Returning to FIG. 2, in step S18, energy transmissibility between minute elements, including incident acoustic energy (acoustic element) information of solid-borne sound obtained by converting the vibration energy (vibration element) possessed by the member element by the "coupling element" And, using the incident energy from the noise/vibration source M to each microelement, the simultaneous equations by the boundary energy integration method, with the energy incident on each microelement as an unknown, considering reflection, diffraction, and transmission, are as follows: It is constructed as shown in (Formula 7).

In this (equation 7), the first term on the left side is a term related to reflection, the second term is a term related to diffraction, the third term is a term related to transmission, and the fourth term is a term related to noise source 1. This is the term for direct propagation and the fifth term is for diffraction propagation from the noise source.

where x _j , y _i , y _k are the node points of the meshed microelements, and we assume that the intensities in the microelements are all equal to the nodal point values. These equations are simultaneous equations relating to the energy balance between minute elements forming the boundary surface of the sound field, as shown in FIG. Each parameter has the relationship shown in FIG. τ(j) represents transmittance. Also, R(y′, x _j , y _k ) indicates the reflection coefficient at x _j and is represented by the following (Equation 8).

N, M, and L are the number of reflection paths, the number of diffraction paths, and the number of transmission paths, respectively. Ns and Ms are the number of sound sources reached by direct sound and the number of sound sources reached by diffraction paths, respectively. α(j) is the sound absorption coefficient, τ(j) is the transmittance, and d(j) is the diffuse reflection coefficient (hypothetical, but according to Lambert Law, the ratio of the diffusely reflected energy to the incident energy. There is specular reflection energy except diffuse reflection).

SPLf(i, _j ) is the sound pressure level at xj when there is an omnidirectional sound source of unit power at _yi , as shown in FIG. Qs is the directional characteristic of the sound source, and Ws is the power of the sound source.
Then, in step S19, the above simultaneous equations are solved, and in step S20, the incident energy from the sound source and other minute elements is calculated for each minute element. That is, by solving the above equation, the acoustic incident energy to each minute element can be obtained in consideration of multiple reflections, multiple diffractions, sound transmission, and their combined effects.

In step S21, the acoustic incident energy incident on each sound receiving position directly from the noise/vibration source M or through a path of only diffraction is calculated. In step S22, the product sum of the energy transmissibility obtained in step S8 and the acoustic incident energy to each minute element obtained in step S20 is obtained, and the acoustic incident energy incident on each sound receiving position from each minute element is obtained. Calculate

Then, in step S23, the acoustic incident energy obtained in step S22 and the acoustic incident energy obtained in step S21 at each sound receiving position are synthesized, and the noise level at each sound receiving position is calculated based on the following (Equation 9). Calculate Then, the noise level distribution (sound pressure contour) within the prediction range is obtained from the noise level at each sound receiving position. The obtained noise distribution is displayed on a monitor or printed on paper.

Next, the action and effect of the propagated sound prediction method using the propagated sound prediction apparatus of this embodiment will be described.
Here, in recent years, there are many cases in which renovation work is carried out while people continue to work as before in rooms other than the repaired area, among the renovation work of buildings. In that case, the vibration generated by the renovation work propagates through the frame and shakes the walls of the living room where people are occupied.
Therefore, in addition to the noise propagating in the air, there is a problem that consideration must be given to solid-borne sound that generates noise. In other words, it is necessary to quickly and accurately analyze in advance how much structure-borne sound will be generated in order to study noise countermeasures.

However, in the past, each person in charge had to individually create a calculation formula for this analysis and attempt the analysis, and there was no unified prediction system. In addition, it has been impossible to predict the sound environment of renovation work noise and demolition work noise that affects the entire building efficiently at a practical level.
On the other hand, according to the propagated sound prediction method using the propagated sound prediction apparatus of the present embodiment, the structure B, such as a building, is divided into a plurality of microelements to which acoustic properties are given, and a vibration physical property is given. Simultaneously calculate multiple reflections, multiple diffractions, sound transmissions, and their combined effects occurring in structure B by modeling the structure with multiple member elements and solving the exchange of energy between the member elements and minute elements. can.

In particular, by the transmitted sound prediction method using the transmitted sound prediction apparatus of the present embodiment, it is practically possible to simultaneously consider both the airborne sound and solid-borne sound for the entire structure such as a building and efficiently predict it. It becomes possible.
That is, according to the propagated sound prediction method using the propagated sound prediction apparatus of the present embodiment, as shown in FIG. , S7). Then, based on the incident vibration energy from the noise/vibration source to the member elements and the vibration energy transmissibility between the member elements, the acoustic radiation energy of the structure model is calculated by the statistical energy analysis method (steps S11 to S16). .
Furthermore, the acoustic radiation energy, which is the vibration element, is converted into the incident acoustic energy of the structure-borne sound, which is the acoustic element, via the coupling element (step S17). Then, based on the incident acoustic energy of the structure-borne sound, the noise level at the sound receiving position is predicted by the boundary energy integration method (steps S18 to S23). Therefore, by combining the "vibration element" with the "acoustic element" by the "coupling element", the air-borne sound and solid-borne sound can be predicted simultaneously.

In particular, according to the propagated sound prediction method using the propagated sound prediction apparatus of the present embodiment, as shown in FIG. Structures are modeled by members and elements. Then, the incident acoustic energy of the airborne sound is calculated based on the incident acoustic energy from the noise/vibration source to the minute elements and the acoustic energy transmissibility between the minute elements.
Furthermore, the acoustic radiation energy of the structure model is calculated by a statistical energy analysis method based on the incident vibration energy from the noise/vibration source to the member elements and the vibration energy transmissibility between the member elements. Then, the acoustic radiation energy of the structure model is converted into incident acoustic energy of solid-borne sound via the coupling elements. Then, the noise level at the sound receiving position is predicted by the boundary energy integration method based on the incident acoustic energy of the air-borne sound and the incident acoustic energy of the solid-borne sound. Therefore, air-borne sound and solid-borne sound can be predicted simultaneously.

That is, according to the propagated sound prediction method using the propagated sound prediction apparatus of the present embodiment, for example, when building B is used by resident P and renovation work and partial demolition work are performed in the same building, Generated structure-borne sound and air-borne sound can be predicted simultaneously.

Therefore, the present invention can be applied to prediction of construction noise for repair work and partial demolition work carried out by the client while using the target building. Further, according to the transmitted sound prediction method using the transmitted sound prediction apparatus of the present embodiment, the airborne sound and the solid-borne sound can be calculated simultaneously. Therefore, it is possible to compare and study which influence is stronger, and to study soundproofing and antivibration measures more efficiently than before. In addition, the calculation time is short, and analysis with high practicality becomes possible.

In addition, according to the transmitted sound prediction method using the transmitted sound prediction device of the present embodiment, noise generated by construction (generated by vibration Composite sound of solid-borne sound and air-borne sound) can be predicted in advance. Therefore, it can be used for selecting the construction method and examining the countermeasure method for the countermeasure range.

In addition, according to the transmitted sound prediction method using the transmitted sound prediction apparatus of the present embodiment, the noise of equipment that causes both the generated noise (airborne sound) and the generated vibration (structure-borne sound) to be a problem is predicted. can. Therefore, it can be applied to study soundproofing and antivibration measures for equipment that generates a large amount of noise and vibration.

In addition, according to the transmitted sound prediction method using the transmitted sound prediction apparatus of the present embodiment, the noise of equipment that generates both noise and vibration (complex sound of solid-borne sound and air-borne sound generated by vibration) is approximated on an energy basis, so the amount of meshing can be reduced, and with simple input conditions, it is possible to predict in advance with high accuracy in a short time. Therefore, the prediction work can be standardized and made efficient, and it can be used for examining soundproofing and vibrationproofing measures for this type of equipment.

Further, according to the propagated sound prediction method using the propagated sound prediction apparatus of the present embodiment, it is possible to visualize the state of attenuation in the process of propagation of sound or vibration. Therefore, the range affected by the noise is easy to understand, and the range requiring countermeasures can be efficiently determined. Furthermore, it can be effectively used as a presentation tool because the results can be displayed visually.

In particular, it is important in presentations to "visualize" results that are easy for customers to understand, and it is possible to present analysis results in visual terms. Since the transmitted sound prediction apparatus of the present embodiment is capable of unified analysis of solid-borne sound, it can be utilized in construction competitions.
In addition, since it is possible to provide a unified transmitted sound prediction system that is easy to input and highly accurate, it is possible to consider in advance how much noise will be in the living room, and it will be possible to consider the construction plan more appropriately according to the customer's needs. .

In addition to renovation work, buildings with deteriorated functions (hospitals, schools, government buildings), such as a rolling plan in which a part of an existing building is demolished to secure the site and construct a new building while maintaining its function, etc.), it is also effective for considering necessary countermeasures by analyzing structure-borne sound during construction, which is a problem in renewal work.

As described above, according to the transmitted sound prediction method using the transmitted sound prediction apparatus of the present embodiment, airborne sound and solid-borne sound can be predicted at the same time. The method and device for predicting propagated sound according to the present invention are not limited to the above-described embodiments, and various modifications are possible without departing from the scope of the present invention.

1 slab (member element)
2 beam (member element)
3 pillars (member elements)
As Air-borne sound Ss Solid-borne sound C Coupling element B Building (structure)
M Construction Machinery (Noise/Vibration Source)
P people (residents)
R living room (sound receiving position)

Claims (2)

modeling the structure into a plurality of member elements with vibration physics attached;
calculating the acoustic radiation energy of the structure model by a statistical energy analysis method based on the incident vibration energy from the noise/vibration source to the member elements and the vibration energy transmissibility between the member elements;
converting the acoustic radiation energy into incident acoustic energy of structure-borne sound via a coupling element;
predicting a noise level at a sound receiving position by a boundary energy integration method based on the incident acoustic energy of the solid-borne sound; and a computer executing the program. Propagated sound prediction device. modeling a structure with a plurality of microelements to which acoustic properties are assigned and a plurality of member elements to which vibration physical properties are assigned;
calculating incident acoustic energy of airborne sound based on incident acoustic energy from a noise/vibration source to said microelements and acoustic energy transmissibility between said microelements;
calculating the acoustic radiation energy of the structure model by a statistical energy analysis method based on the incident vibration energy from the noise/vibration source to the member elements and the vibration energy transmissibility between the member elements;
converting acoustic radiation energy of the structure model into incident acoustic energy of structure-borne sound via coupling elements;
predicting a noise level at a sound receiving position by a boundary energy integration method based on the incident acoustic energy of the air-borne sound and the incident acoustic energy of the solid-borne sound; and executing the program. A propagated sound prediction device comprising: a computer;

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