This application claims priority to Japanese Patent Application No. 2021-030251 filed on Feb. 26, 2021, which is incorporated herein by reference in its entirety including the specification, claims, drawings, and abstract.
The present specification discloses a sound transmission analyzer for a panel member of a vehicle.
Conventionally, technologies have been proposed which can be used to analyze sound radiated to the inner side of a panel member (e.g., a cabin) of a vehicle when the panel member vibrates.
For example, JP 2019-114114A discloses a vehicle panel member vibration analyzer configured to calculate a sound pressure sensitivity P/F indicating the relationship between external force F and a sound pressure P at a measurement position on the basis of equivalent radiated power (acoustic energy radiated from a vehicle panel) of the panel member when the external force F is imposed on the panel member of the vehicle, a soundproof material surface vibration ratio that is a ratio between vibration amplitudes of the panel member and a soundproof material provided on the inner side of the panel member, and an acoustic transfer function from an inner surface of the panel member to a preset measurement position, which are obtained by simulation.
In the technology according to JP 2019-114114A, the sound pressure sensitivity P/F involving the external force F imposed on the panel member is calculated. Here, the external force F in JP 2019-114114A corresponds to an input of force that generates vibrations transmitted through an object (solid propagating sound). That is, in the technology according to JP 2019-114114A, the sound pressure sensitivity P/F for the solid propagating sound is calculated.
However, an airborne sound propagating through the air from a sound source may be input to the panel member. Thus, it is useful to obtain an acoustic transfer function involving the transmission sound in which the sound pressure is transmitted through the panel member in consideration of the airborne sound input to the panel member.
The purpose of a sound transmission analyzer for a panel member of a vehicle as disclosed herein is to obtain an acoustic transfer function involving a transmission sound transmitted through the panel member from a sound source in consideration of an airborne sound that propagates through the air from the sound source outside the panel member and is input to an outer surface of the panel member.
A sound transmission analyzer for a panel member of a vehicle as disclosed herein includes a sound transmission analyzing unit configured to calculate an acoustic transfer function from a sound source via the air to an inner surface of a panel member on the basis of an outside-of-panel acoustic transfer function that is an acoustic transfer function involving an airborne sound from the sound source located outside the panel member of the vehicle to an outer surface of the panel member, and a panel transmission function that is an acoustic transfer function from the outer surface of the panel member to the inner surface of the panel member.
The outside-of-panel acoustic transfer function is an acoustic transfer function involving an airborne sound from the sound source to the outer surface of the panel member. The acoustic transfer function from the sound source to the inner surface of the panel member as calculated by such a configuration is an acoustic transfer function in consideration of an airborne sound that propagates through the air from the sound source and is input to the outer surface of the panel member.
According to the sound transmission analyzer for a panel member of a vehicle as disclosed herein, it is possible to obtain an acoustic transfer function involving a transmission sound transmitted through the panel member from a sound source in consideration of an airborne sound that propagates through the air from the sound source outside the panel member and is input to the outer surface of the panel member.
Embodiment(s) of the present disclosure will be described based on the following figures, wherein:
The sound transmission analyzer 10 is a device for analyzing a sound emitted from a sound source located outside a body panel (on the vehicle outer side) of the vehicle and radiated through the body panel to the inner side of the body panel (on the vehicle inner side). The body panel is a component of a vehicle frame part, and is a metal part enclosing a cabin space. In the body panel, a plurality of panel sections each constituting a part of the body panel can be defined. Examples of the panel section include, but are not limited to, a cowl panel or a dash panel positioned forwardly of the cabin space, a floor panel or a tunnel panel below the cabin space, a roof panel above the cabin space, and a back panel behind the cabin space.
In particular, in this embodiment, the sound transmission analyzer 10 analyzes a sound radiated to the cabin side from an inner surface of at least one panel member while the body panel of the vehicle is conceptually divided into a plurality of panel members. As described above, the plurality of panel sections can be defined in the body panel. Each panel section conceptually includes one or more panel members.
A communication unit 12 includes, for example, a network adapter. The communication unit 12 can communicate with other devices (e.g., a user terminal used by a user, a device configured to execute a simulation that will be described later).
A display unit 14 includes, for example, a liquid crystal panel. Various screens are displayed on the display unit 14. In particular, the display unit 14 in this embodiment displays calculation results of the sound transmission analyzing unit 26 described later.
A storage unit 16 includes, for example, a hard disk drive (HDD), a solid state drive (SSD), an embedded multimedia card (eMMC), a read only memory (ROM), and/or a random access memory (RAM). The storage unit 16 is configured to store a sound transmission analysis program for causing each unit of the sound transmission analyzer 10 to function.
In addition, the storage unit 16 in this embodiment is configured to store an outside-of-panel acoustic transfer function 18, a panel transmission function 20, a soundproof material surface vibration ratio 22, and an inside-of-panel acoustic transfer function 24. Note that the outside-of-panel acoustic transfer function 18, the panel transmission function 20, the soundproof material surface vibration ratio 22, and the inside-of-panel acoustic transfer function 24 may be stored not in the storage unit 16 but in another device accessible from the sound transmission analyzer 10.
The outside-of-panel acoustic transfer function 18, the panel transmission function 20, the soundproof material surface vibration ratio 22, and the inside-of-panel acoustic transfer function 24 are acquired by actual measurement or simulation for each panel member obtained by conceptually dividing the body panel of the vehicle. Note that in the case of acquisition by simulation, the simulation may be executed by the sound transmission analyzer 10 or may be executed by a device other than the sound transmission analyzer 10.
Before describing the outside-of-panel acoustic transfer function 18, the panel transmission function 20, the soundproof material surface vibration ratio 22, and the inside-of-panel acoustic transfer function 24, the panel member(s) will be described.
As illustrated in
In addition, each panel member 36 is divided into elements 38 that are smaller sub-regions (in
The area of each panel member 36 is set according to the frequency or wavelength of a sound to be analyzed. Specifically, the area of each panel member 36 is set such that the wavelength of a sound to be analyzed is sufficiently smaller than the area of the panel member 36. More specifically, the area of each panel member 36 is set such that the area of the panel member 36 includes at least one wavelength of a sound to be analyzed. For example, if the sound to be analyzed has a frequency in a medium region (from 200 to 630 [Hz]), the area of each panel member 36 is set to 300×300 [mm] or larger.
Hereinafter, the outside-of-panel acoustic transfer function 18, the panel transmission function 20, the soundproof material surface vibration ratio 22, and the inside-of-panel acoustic transfer function 24 will be described.
The outside-of-panel acoustic transfer function 18 is an acoustic transfer function involving an airborne sound that is a sound propagating through the air from a sound source outside the body panel 30 (i.e., the panel member 36) to an outer surface of the panel member 36. The outside-of-panel acoustic transfer function 18 will be described with reference to
Then, the volume velocity Q of the speaker 40, and the sound pressure Pi,panel of a sound acquired by the microphone 42 when the sound is output from the speaker 40, are acquired. The volume velocity Q of the speaker 40 is the product of the area of cone portion, which is a vibration part of the speaker 40, and the vibration velocity, and means that the larger the value, the louder the sound. The outside-of-panel acoustic transfer function 18 is expressed by a ratio between the volume velocity Q of the speaker 40 and the sound pressure Pi,panel at the microphone 42, that is, Pi,panel/Q [dB]. The subscript i indicates a panel member 36. The outside-of-panel acoustic transfer function 18 is obtained for each panel member 36.
It can be said that the outside-of-panel acoustic transfer function 18 is an indicator that indicates how easily a sound in the air is transmitted from the sound source to the outer surface 36o of the panel member 36. As the outside-of-panel acoustic transfer function 18 becomes larger, the sound from the sound source is more readily transmitted to the outer surface 36o of the panel member 36. On the other hand, as the outside-of-panel acoustic transfer function 18 becomes smaller, the sound from the sound source is less readily transmitted to the outer surface 36o of the panel member 36.
The outside-of-panel acoustic transfer function 18 for each panel member 36 can also be acquired by simulation using CAE. Specifically, 3D data about the body panel 30 divided by the mesher is read into the CAE. Then, the CAE is used to simulate installation of the speaker 40 at the sound source position, installation of the microphone 42 in the vicinity of the outer surface 36o of the panel member 36, measurement of the volume velocity Q of the speaker 40, and the sound pressure Pi,panel of the sound acquired by the microphone 42.
The panel transmission function 20 is an acoustic transfer function from the outer surface 36o of the panel member 36 to the inner surface of the panel member 36. Since the panel transmission function 20 is obtained based on equivalent radiated power representing the amount of acoustic energy radiated from the panel member 36, the transmitted radiation power will first be described.
The equivalent radiated power ERP is calculated by the following Formula 1.
In Formula 1, ρ0 represents the density of air, c0 represents the speed of sound, σ represents a radiation attenuation coefficient, variable j represents each element 38 defined in the panel member 36 for which the panel transmission function 20 is calculated, N represents the number of elements 38 in the panel member 36, and Vj represents the vibration velocity of each element 38, in particular, the speed in the normal direction of the panel member 36,
represents the conjugate complex number of the vibration velocity Vj of each element 38, and Sj represents the area of each element 38.
The radiation attenuation coefficient σ is an indicator that represents the efficiency of converting the vibration of the panel member 36 into sound. For example, depending on a situation around the panel member 36 (e.g., a positional relationship with other members), there may be a situation where it is difficult to convert the vibration of the panel member 36 into sound. In this case, by inputting a value for the radiation attenuation coefficient σ, it is possible to obtain equivalent radiated power ERP in consideration of the efficiency of converting the vibration of the panel member 36 into sound. In the case without considering the efficiency of converting the vibration of the panel member 36 to sound, the radiation attenuation coefficient σ for every panel member 36 is set to 1.
The product of the vibration velocity Vj and its conjugate complex number is the square of the vibration velocity Vj of the element 38 in the panel member 36 when the phase is not considered. Thus,
(Vj·
is the product of the square of the vibration velocity Vj of an element 38 without phase considered and the area of the element 38. Thus, it can be said that the equivalent radiated power ERP is calculated based on a value obtained by totaling the product of the square of the vibration velocity Vj without phase considered and the area Sj for each element 38 included in the panel member 36.
As described above, the equivalent radiated power ERP is calculated based on the vibration velocity Vj of each element 38 constituting the panel member 36, and the vibration velocity Vj of each element 38 is obtained by simulation in CAE.
The CAE is used to simulate vibration of each element 38 when a sound pressure of 1 [Pa] is applied to the panel member 36. Then, the vibration velocity Vj of each element 38 is acquired. Note that the vibration velocity Vj of each element 38 included in the panel member 36 can be different depending on factors such as the structure of the panel member 36. For example, as shown in
As is clear from Formula 1, the equivalent radiated power ERP is a value that varies depending on the vibration velocity Vj of each element 38 (which may be referred to as a sound pressure input to the panel member 36). Specifically, as the velocity Vj increases, the equivalent radiated power ERP also increases. Thus, the equivalent radiated power ERP does not by itself represent the panel transmission function 20 of the panel member 36.
The equivalent radiated power ERP is set to a value that does not depend on the vibration velocity Vj of each element 38 (that is, the sound pressure input to the panel member 36). To achieve this, as shown in the following Formula 2, the vibration velocity Vj and its conjugate complex number on the right side of Formula 1 are each divided by the sound pressure input to the panel member 36, namely, Pi,panel.
The parameter represented by Formula 2 represents the amount of acoustic energy radiated from the panel member 36 when the sound pressure Pi,panel is input to the outer surface 36o of the panel member 36 (in other words, when the sound pressure Pi,panel is provided as input conditions). That is, the parameter represented by Formula 2 is the acoustic transfer function from the outer surface 36o of the panel member 36 to the inner surface of the panel member 36, namely, the panel transmission function 20. As used herein, the panel transmission function 20 is denoted as τi,panel. Formula 2 may be converted to express τi,panel by the following Formula 3.
As described above, the panel transmission function 20 is calculated for each panel member 36. As the panel transmission function 20 becomes larger, the sound from the outer surface 36o of the panel member 36 is more readily transmitted to the inner surface 36i of the panel member 36. On the other hand, as the panel transmission function 20 becomes smaller, the sound from the outer surface 36o of the panel member 36 is less readily transmitted to the inner surface 36i of the panel member 36.
As described above, the equivalent radiated power ERP is calculated based on the vibration velocity Vj while the phase of the element 38 is not considered. However, the amount of acoustic energy radiated from the panel member 36 by the vibration of each element 38 is more suitably calculated while the phase of the vibration velocity Vj is considered. Specifically, the phase of the vibration velocity Vj is sometimes not considered. In this case, if the vibration velocity Vj is negative as illustrated in
Thus, the panel transmission function 20 may be acquired based on, instead of the equivalent radiated power ERP, the equivalent radiated power with phase considered ERPWPC in which the phase of the vibration velocity Vj is considered.
The equivalent radiated power with phase considered ERPWPC is calculated by Formula 4 below.
As shown in Formula 4, in the equivalent radiated power with phase considered ERPWPC, the product of the vibration velocity Vj and the area Sj for each element 38 is summed, and the absolute value of the sum is squared (the numerator on the right side of Formula 4). The reason why the sum is squared is because the equivalent radiated power ERP is expressed including the square of the vibration velocity Vj. When the sum of the products of the vibration velocity Vj and the area Sj is squared, the sum of the areas Sj of the respective elements 38 is also squared. Accordingly, the square of the sum of the products of the vibration velocity Vj and the area Sj is divided by the sum of the areas Sj of the respective elements 38 (the denominator on the right side of Formula 4).
In Formula 4, since the vibration velocities Vj of the plurality of elements 38 are added as they are, the equivalent radiated power in which the phase of the vibration velocity Vj is considered, that is, the equivalent radiated power with phase considered ERPWPC, can be calculated according to Formula 4.
If the panel transmission function 20 is acquired based on the equivalent radiated power with phase considered ERPWPC, τi,panel can be expressed by Formula 5 below.
In the following description, it is assumed that the panel transmission function 20 is calculated based on the equivalent radiated power with phase considered ERPWPC.
The soundproof material surface vibration ratio 22 is a ratio between a vibration velocity Vi,panel in the normal direction of the panel member 36 and a vibration velocity Vi,trim in the normal direction of a surface (inner surface) of the soundproof material provided on the inner side of the panel member 36.
When the soundproof material surface vibration ratio 22 is acquired by actual measurement, an accelerometer 46 is attached to the outer surface 36o of the panel member 36, and an accelerometer 48 is provided on the inner surface 44i of the soundproof material 44. Then, the vibration velocity Vi,panel of the outer surface 36o of the panel member 36 is calculated by time-integrating the acceleration at the panel member 36 as measured by the accelerometer 46, and the vibration velocity Vi,trim of the inner surface 44i of the soundproof material 44 is calculated by time-integrating the acceleration at the inner surface 44i of the soundproof material 44 as measured by the accelerometer 48. Note that since the panel member 36 can be regarded as a rigid body, the vibration velocities of the outer surface 36o and the inner surface 36i can be regarded as the same.
The soundproof material surface vibration ratio 22 is expressed by the square of the ratio between the vibration velocity Vi,panel of the panel member 36 and the vibration velocity Vi,trim of the inner surface 44i of the soundproof material 44. As used herein, the soundproof material surface vibration ratio 22 is described as Ti,trim. Ti,trim is expressed by the following Formula 6.
As described above, the soundproof material surface vibration ratio 22 is acquired for each panel member 36. As a matter of course, the soundproof material surface vibration ratio 22 is not acquired for the panel member 36 that does not have the soundproof material 44 provided on the inner side.
The soundproof material surface vibration ratio 22 for each panel member 36 can also be acquired by simulation using CAE. Specifically, 3D data about the body panel 30 divided by the mesher is read into the CAE. The panel member 36 is vibrated in simulation. Then, measurement of the vibration velocity Vi,panel of the outer surface 36o of each panel member 36 and measurement of the vibration velocity Vi,trim of the inner surface 44i of the soundproof material 44 provided on the inner side of each panel member 36 are simulated on the CAE.
It can be said that the soundproof material surface vibration ratio 22 is an acoustic transfer function from the inner surface 36i of the panel member 36 to the inner surface 44i of the soundproof material 44. As the soundproof material surface vibration ratio 22 becomes larger, the sound from the inner surface 36i of the panel member 36 is more readily transmitted to the inner surface 44i of the soundproof material 44. On the other hand, as the soundproof material surface vibration ratio 22 becomes smaller, the sound from the inner surface 36i of the panel member 36 is less readily transmitted to the inner surface 44i of the soundproof material 44.
The inside-of-panel acoustic transfer function 24 is an acoustic transfer function involving an airborne sound from the inner surface 44i of the soundproof material 44 to a measurement position (inside the cabin) on the inner side of the panel member 36. Alternatively, the inside-of-panel acoustic transfer function 24 is an acoustic transfer function involving an airborne sound from the inner surface 36i of the panel member 36 to a measurement position on the inner side of the panel member 36. The inside-of-panel acoustic transfer function 24 will be described with reference to
Then, the volume velocity Qi,trim of the speaker 50 when the sound is output from the speaker 50, and the sound pressure Pear of the sound obtained by the microphone 52, are acquired. The inside-of-panel acoustic transfer function 24 is expressed by a ratio between the volume velocity Qi,trim at the speaker 50 and the sound pressure Pear at the microphone 52, namely, Pear/Qi,trim [dB].
It can be said that the inside-of-panel acoustic transfer function 24 is an indicator that indicates how easily an airborne sound is transmitted from the inner surface 44i of the soundproof material 44 to the measurement position. As the inside-of-panel acoustic transfer function 24 becomes larger, the sound from the inner surface 44i of the soundproof material 44 is more readily transmitted to the measurement position. As the inside-of-panel acoustic transfer function 24 becomes smaller, the sound from the inner surface 44i of the soundproof material 44 is less readily transmitted to the measurement position.
The inside-of-panel acoustic transfer function 24 is calculated for each panel member 36.
For the panel member 36 provided with the soundproof material 44, as described above, Pear/Qi,trim is calculated as the first inside-of-panel acoustic transfer function. However, for the panel member 36 with which the soundproof material 44 is not provided, the acoustic transfer function involving an airborne sound from the inner surface 36i of the panel member 36 to the measurement position is calculated as the second inside-of-panel acoustic transfer function. Specifically, the speaker 54 is installed near the inner surface 36i of the panel member 36, and the microphone 52 is installed at the measurement position. Then, the volume velocity Qi,panel at the speaker 54 when the sound is output from the speaker 54, and the sound pressure Pear of the sound obtained with the microphone 52, are acquired. In this case, the inside-of-panel acoustic transfer function 24 is expressed by a ratio between the volume velocity Qi,panel at the speaker 54 and the sound pressure Pear at the microphone 52, namely, Pear/Qi,panel [dB].
The inside-of-panel acoustic transfer function 24 for each panel member 36 can also be acquired by simulation using CAE. Specifically, 3D data about the body panel 30 divided by the mesher is read into the CAE. Installation of the speaker 54 or 50 in the vicinity of the inner surface 44i of the soundproof material 44 (or the inner surface 36i of the panel member 36), installation of the microphone 52 at the sound source position, measurement of the volume velocity Qi,trim (or Qi,panel) at the speaker 50, and measurement of the sound pressure Pear at the microphone 52 are simulated on the CAE.
Back to
The sound transmission analyzing unit 26 is configured to be able to calculate, based on the outside-of-panel acoustic transfer function 18 and the panel transmission function 20, an acoustic transfer function from the sound source via the air to the inner surface 36i of a specific panel member 36. As described above, the outside-of-panel acoustic transfer function 18 is an acoustic transfer function involving an airborne sound from the sound source to the outer surface 36o of the panel member 36. The panel transmission function 20 is an acoustic transfer function from the outer surface 36o of the panel member 36 to the inner surface 36i of the panel member 36. Thus, the outside-of-panel acoustic transfer function 18 and the panel transmission function 20 may be used in combination to give an acoustic transfer function from the sound source via the air to the inner surface 36i of a specific panel member 36. As the acoustic transfer function becomes larger, the sound from the sound source is more readily transmitted to the inner surface 36i of the panel member 36. On the other hand, as the acoustic transfer function becomes smaller, the sound from the sound source is less readily transmitted to the inner surface 36i of the panel member 36.
The acoustic transfer function from the sound source via the air to the inner surface 36i of the specific panel member 36 can be expressed by Formula 7 below.
That is, the acoustic transfer function from the sound source via the air to the inner surface 36i of the specific panel member 36 is expressed by the product of the outside-of-panel acoustic transfer function 18 and the panel transmission function 20.
As illustrated in
In addition, the sound transmission analyzing unit 26 can calculate, based on the outside-of-panel acoustic transfer function 18, the panel transmission function 20, and the soundproof material surface vibration ratio 22, an acoustic transfer function from the sound source via the air and the specific panel member 36 to the inner surface 44i of the soundproof material 44 provided on the inner side of the panel member 36. As described above, the soundproof material surface vibration ratio 22 is an acoustic transfer function from the inner surface 36i of the panel member 36 to the inner surface 44i of the soundproof material 44. Thus, the outside-of-panel acoustic transfer function 18, the panel transmission function 20, and the soundproof material surface vibration ratio 22 may be used in combination to give an acoustic transfer function from the sound source, via the air and the specific panel member 36, to the inner surface 44i of the soundproof material 44. As the acoustic transfer function becomes larger, the sound from the sound source is more readily transmitted to the inner surface 44i of the soundproof material 44. On the other hand, as the acoustic transfer function becomes smaller, the sound from the sound source is less readily transmitted to the inner surface 44i of the soundproof material 44.
The acoustic transfer function from the sound source via the air and the specific panel member 36 to the inner surface 44i of the soundproof material 44 can be expressed by Formula 8 below.
That is, the acoustic transfer function from the sound source via the air and the specific panel member 36 to the inner surface 44i of the soundproof material 44 is expressed by the product of the outside-of-panel acoustic transfer function 18, the panel transmission function 20, and the soundproof material surface vibration ratio 22.
In addition to the outside-of-panel acoustic transfer function 18 and the panel transmission function 20, the soundproof material surface vibration ratio 22 is also acquired for each frequency as shown in
In addition, the sound transmission analyzing unit 26 can calculate, based on the outside-of-panel acoustic transfer function 18, the panel transmission function 20, the soundproof material surface vibration ratio 22, and the inside-of-panel acoustic transfer function 24, an acoustic sensitivity Pi,ear/Q, that is, an acoustic transfer function from the sound source, via the air, the specific panel member 36, and the soundproof material 44 provided on the inner side of the panel member 36, to the measurement position. As mentioned above, the inside-of-panel acoustic transfer function 24 (in this case, the first inside-of-panel acoustic transfer function Pear/Qi,trim) is an acoustic transfer function involving an airborne sound from the inner surface 44i of the soundproof material 44 to the measurement position. Thus, the outside-of-panel acoustic transfer function 18, the panel transmission function 20, the soundproof material surface vibration ratio 22, and the inside-of-panel acoustic transfer function 24 may be used in combination to give the acoustic sensitivity Pi,ear/Q. As the acoustic sensitivity Pi,ear/Q becomes larger, the sound from the sound source is more readily transmitted to the measurement position. On the other hand, as the acoustic sensitivity Pi,ear/Q becomes smaller, the sound from the sound source is less readily transmitted to the measurement position.
The acoustic sensitivity Pi,ear/Q can be expressed by the following Formula 9.
That is, the acoustic sensitivity Pi,ear/Q is expressed by the product of the outside-of-panel acoustic transfer function 18, the panel transmission function 20, the soundproof material surface vibration ratio 22, and the inside-of-panel acoustic transfer function 24.
Note that in the upper and middle expressions of Formula 9, the inside-of-panel acoustic transfer function 24 is expressed by Pear/Pi,trim. Meanwhile, in the lower expression of Formula 9, 2ρ0c0/S=P/Q. Thus, the panel transmission function 20 is expressed by ERPWPC/Pi,panel2, and the inside-of-panel acoustic transfer function 24 is expressed by Pear/Qi,trim.
In addition to the outside-of-panel acoustic transfer function 18, the panel transmission function 20, and the soundproof material surface vibration ratio 22, the inside-of-panel acoustic transfer function 24 is also acquired for each frequency as illustrated in
For the panel member 36 with which the soundproof material 44 is not provided, the sound transmission analyzing unit 26 can calculate, based on the outside-of-panel acoustic transfer function 18, the panel transmission function 20, and the inside-of-panel acoustic transfer function 24 (in this case, the second inside-of-panel acoustic transfer function Pear/Qi,panel), the acoustic sensitivity from the sound source via the air and the specific panel member 36 to the measurement position. The acoustic sensitivity Pi,ear/Q in this case can be expressed by the following Formula 10.
In addition, the sound transmission analyzing unit 26 can obtain, by totaling the acoustic sensitivities Pi,ear/Q for a plurality of the panel members 36, the total acoustic sensitivity Pear/Q, which is an acoustic transfer function from the sound source to the measurement position in consideration of a plurality of acoustic transfer paths from the sound source via the air and each panel member 36 to the measurement position. Specifically, the sound transmission analyzing unit 26 can obtain the total acoustic sensitivity Pear/Q by totaling the products of the outside-of-panel acoustic transfer function 18, the panel transmission function 20, the soundproof material surface vibration ratio 22, and the inside-of-panel acoustic transfer function 24 for each panel member 36. As the total acoustic sensitivity Pear/Q becomes larger, the sound from the sound source is more readily transmitted to the measurement position. On the other hand, as the total acoustic sensitivity Pear/Q becomes smaller, the sound from the sound source is less readily transmitted to the measurement position.
The total acoustic sensitivity Pear/Q can be expressed by the following Formula 11.
M in Formula 11 is the number of panel members 36 included in the body panel 30 of the vehicle. Thus, the total acoustic sensitivity Pear/Q illustrated in Formula 10 is an acoustic transfer function from the sound source to the measurement position in consideration of a plurality of acoustic transfer paths from the sound source to the measurement position via all the panel members 36 included in the body panel 30 of the vehicle.
Note that a case is considered where, among a plurality of panel members 36 constituting the body panel 30 of the vehicle, some panel members provided with the soundproof material 44 and other panel members not provided with the soundproof material are mixed. In this case, the sound transmission analyzing unit 26 calculates the acoustic sensitivity Pi,ear/Q using the outside-of-panel acoustic transfer function 18, the panel transmission function 20, the soundproof material surface vibration ratio 22, and the first inside-of-panel acoustic transfer function Pear/Qi,trim for each panel member 36 provided with the soundproof material 44, and calculates the acoustic sensitivity Pi,ear/Q using the outside-of-panel acoustic transfer function 18, the panel transmission function 20, and the second inside-of-panel acoustic transfer function Pear/Qi,panel for each panel member 36 not provided with the soundproof material 44.
The acoustic sensitivity Pi,ear/Q for each panel member 36 is acquired for each frequency. Thus, the sound transmission analyzing unit 26 also acquires the total acoustic sensitivity Pear/Q for each frequency by totaling the acoustic sensitivity Pi,ear/Q for each panel member 36 for each frequency. The sound transmission analyzing unit 26 can generate a graph indicating the relationship between the total acoustic sensitivity Pear/Q and the frequency.
As described above, the body panel 30 of the vehicle is configured to include a plurality of panel sections 32 each including one or more panel members 36. Here, the sound transmission analyzing unit 26 can calculate, for each panel section 32, a section acoustic sensitivity Pk,ear/Q (section acoustic sensitivity Pk,ear/Q from the sound source via the panel section 32 to the measurement position) for the panel section 32 on the basis of the acoustic sensitivities Pi,ear/Q of one or more panel members 36 constituting the panel section 32. Note that the subscript k indicates a panel section 32.
Specifically, the section acoustic sensitivity Pk,ear/Q for a certain panel section 32 can be obtained by totaling the acoustic sensitivities Pi,ear/Q of one or more panel members 36 constituting the panel section 32. For example, the acoustic sensitivities of a plurality of panel members 36 constituting the back panel are totaled to give the section acoustic sensitivity Pk,ear/Q for the entire back panel. The section acoustic sensitivities Pk,ear/Q for all the panel sections 32 constituting the body panel 30 of the vehicle are totaled to give the total acoustic sensitivity Pear/Q.
The sound transmission analyzing unit 26 generates a graph indicating the relationship between the section acoustic sensitivity Pk,ear/Q and a frequency for each panel section 32. The graph is illustrated in
The sound transmission analyzing unit 26 calculates, based on the section acoustic sensitivity Pk,ear/Q for each panel section 32, the contribution of each panel section 32 with respect to the sound transmission from the sound source to the measurement position. For example, when the total acoustic sensitivity Pear/Q is set to 100 [%], the percentage of the section acoustic sensitivity Pk,ear/Q for each panel section 32 in the total acoustic sensitivity Pear/Q is the contribution of each panel section 32. The greater the contribution, the greater the panel section 32 contributes to the sound transmission from the sound source to the measurement position. The section acoustic sensitivity Pk,ear/Q for each panel section 32 is obtained for each frequency. Accordingly, the contribution is also obtained for each frequency. That is, the sound transmission analyzing unit 26 calculates the contribution of each panel section 32 with respect to the sound transmission from the sound source to the measurement position for each frequency.
A user can also read the contribution of each panel section 32 from the graph illustrated in
The sound transmission analyzer 10 according to this embodiment is as described above. The sound transmission analyzer 10 according to this embodiment is configured to calculate an acoustic transfer function involving a transmission sound transmitted through a panel member(s) 36 from a sound source on the basis of the outside-of-panel acoustic transfer function 18, which is an acoustic transfer function involving an airborne sound from the sound source to the outer surface 36o of the panel member 36. Thus, the transmission analyzer according to this embodiment can be used to analyze the sound transmission involving the panel member(s) 36 in consideration of a sound emitted from the sound source, propagated in the air, and input to the outer surface 36o of the panel member 36.
Hereinafter, how the processing of the sound transmission analyzing unit 26 is processed will be described according to the flowchart shown in
In step S10, the sound transmission analyzing unit 26 determines whether or not the outside-of-panel acoustic transfer functions 18 have been acquired and are stored in the storage unit 16 or a device accessible from the sound transmission analyzer 10. In this processing, all the panel members 36 constituting the body panel 30 of the vehicle are analyzed. Thus, in step S10, whether or not the outside-of-panel acoustic transfer functions 18 for all the panel members 36 have been acquired is determined.
In a case where the outside-of-panel acoustic transfer functions 18 for all the panel members 36 have been acquired, the process goes to step S14. In a case where the outside-of-panel acoustic transfer functions 18 for any of the panel members 36 have not been acquired, the process goes to step S12. In step S12, the sound transmission analyzing unit 26 presents a notification for prompting acquisition of the outside-of-panel acoustic transfer functions 18 to a user. Note that the notification is presented by, for example, transmitting a notification message from the communication unit 12 to a user terminal or displaying the notification message on the display unit 14. When the outside-of-panel acoustic transfer functions 18 of interest are acquired by the user, it is determined that the outside-of-panel acoustic transfer functions 18 for all the panel members 36 have been acquired in step S10 again. Then, the process goes to step S14.
In step S14, the sound transmission analyzing unit 26 determines whether or not the panel transmission functions 20 for all the panel members 36 have been acquired and are stored in the storage unit 16 or a device accessible from the sound transmission analyzer 10.
In a case where the panel transmission functions 20 for all the panel members 36 have been acquired, the process goes to step S18. In a case where the panel transmission functions 20 for any of the panel members 36 have not been acquired, the process goes to step S16. In step S16, the sound transmission analyzing unit 26 presents a notification for prompting acquisition of the panel transmission functions 20 to the user. When the panel transmission functions 20 of interest are acquired by the user, it is determined that the panel transmission functions 20 for all the panel members 36 have been acquired in step S14 again. Then, the process goes to step S18.
In step S18, the sound transmission analyzing unit 26 determines whether or not the soundproof material surface vibration ratios 22 for all the panel members 36 provided with the soundproof material 44 have been acquired and are stored in the storage unit 16 or a device accessible from the sound transmission analyzer 10.
In a case where the soundproof material surface vibration ratios 22 for all the panel members 36 provided with the soundproof material 44 have been acquired, the process goes to step S22. In a case where the soundproof material surface vibration ratios 22 for any of the panel members 36 provided with the soundproof material 44 have not been acquired, the process goes to step S20. In step S20, the sound transmission analyzing unit 26 presents a notification for prompting acquisition of the soundproof material surface vibration ratios 22 to the user. When the soundproof material surface vibration ratios 22 of interest are acquired by the user, it is determined that the soundproof material surface vibration ratios 22 for all the panel members 36 provided with the soundproof material 44 have been acquired in step S18 again. Then, the process goes to step S22.
In step S22, the sound transmission analyzing unit 26 determines whether or not the inside-of-panel acoustic transfer functions 24 for all the panel members 36 have been acquired and are stored in the storage unit 16 or a device accessible from the sound transmission analyzer 10.
In a case where the inside-of-panel acoustic transfer functions 24 for all the panel members 36 have been acquired, the process goes to step S26. In a case where the inside-of-panel acoustic transfer functions 24 for any of the panel members 36 have not been acquired, the process goes to step S24. In step S24, the sound transmission analyzing unit 26 presents a notification for prompting acquisition of the inside-of-panel acoustic transfer functions 24 to the user. When the inside-of-panel acoustic transfer functions 24 of interest are acquired by the user, it is determined that the inside-of-panel acoustic transfer functions 24 for all the panel members 36 have been acquired in step S22 again. Then, the process goes to step S26.
In step S26, the sound transmission analyzing unit 26 calculates the total acoustic sensitivity Pear/Q by totaling the products of the outside-of-panel acoustic transfer function 18, the panel transmission function 20, the soundproof material surface vibration ratio 22, and the inside-of-panel acoustic transfer function 24 for the plurality of panel members 36.
In step S28, the sound transmission analyzing unit 26 calculates, for each panel section 32, the section acoustic sensitivity Pk,ear/Q for the panel section 32 by totaling the acoustic sensitivities Pi,ear/Q of one or more panel members 36 constituting the panel section 32. In addition, the sound transmission analyzing unit 26 calculates, based on the section acoustic sensitivity Pk,ear/Q for each panel section 32, the contribution of each panel section 32 with respect to the sound transmission from the sound source to the measurement position.
In step S30, the sound transmission analyzing unit 26 outputs the calculation results of steps S26 and S28. For example, a graph indicating the relationship between the total acoustic sensitivity Pear/Q and a frequency (see
The embodiment of the automatic driving vehicle according to the present disclosure has been described above. However, the automatic driving vehicle according to the present disclosure is not limited to the above embodiment, and various modifications can be made without departing from the gist of the present disclosure.
For example, in the above embodiment, it is assumed that the sound source is an engine, but of course, the sound source is not limited to the engine. For example, the sound source may be a front tire. In this case, the outside-of-panel acoustic transfer function 18 is acquired after the speaker 40 is installed near the front tire.
Number | Date | Country | Kind |
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2021-030251 | Feb 2021 | JP | national |