Gradient helmholtz resonator array design method based on uniform bottle neck, array and equipment

Abstract

The application discloses a gradient Helmholtz resonator array design method based on unified curled neck, an array and equipment, and the method comprises the following steps: determining a target frequency set according to an object to be enhanced; obtaining resonant group information; determining the curled neck parameters of each resonant group according to the resonant group information and a preset processing strategy, and calculating equivalent acoustic inertia parameters; calculating the cavity height of each Helmholtz resonator unit according to the target frequency and the equivalent acoustic inertia parameters corresponding to each Helmholtz resonator unit, and then generating a gradient Helmholtz resonator array model. In the application, the gradient Helmholtz resonator array adopts a gradient Helmholtz resonator array structure with unified curled neck, which can take into account the low-frequency sound signal enhancement and miniaturization of the curled structure, and improve the determination certainty of frequency prediction and the array design efficiency.

Description

Technical Field

[0001] This application relates to the field of acoustic superstructures, and in particular to a design method, array, and device for a gradient Helmholtz resonator array based on a unified curled bottleneck. Background Technology

[0002] In the detection of weak low-frequency acoustic signals and acoustic front-end enhancement, it is often necessary to selectively amplify the sound pressure energy near the target frequency before the acoustic signal enters the sensor. Helmholtz resonators and their arrays are important basic units in low-frequency sound absorption, sound insulation, and sound field manipulation.

[0003] Conventional low-frequency acoustic enhancement structures suffer from a trade-off between low-frequency performance and structural size. For traditional structures such as conventional straight-bottom Helmholtz resonators and quarter-wavelength tubes, lower target frequencies typically require larger cavity volumes or longer acoustic paths. When the target frequency is in the hundreds of hertz or even lower frequency range, the structural size easily exceeds the acceptable range of sensor front-ends, mechanical equipment housings, confined installation spaces, or portable detection devices. Therefore, traditional structures suffer from insufficient miniaturization in low-frequency weak acoustic signal enhancement scenarios. Furthermore, while coiled spatial structures can lower the operating frequency, the target frequency prediction is not direct enough. Coiled channels increase the equivalent acoustic length by folding the propagation path, enabling low-frequency enhancement within a limited space. However, bends, slits, end openings, and local cross-sectional changes in the coiled path introduce additional inertia and losses, causing the actual resonant frequency to deviate from the simple theoretical model. Especially when multiple coiled units form an array, near-field coupling and boundary reflections between units further affect the response frequency. The design of coiled structures in Helmholtz resonator arrays often relies on extensive finite element simulations or experimental corrections, which is inefficient.

[0004] The root cause of the above problems lies in the fact that low-frequency acoustic enhancement relies on a large equivalent acoustic length or a large cavity compliance, while limited installation space restricts the linear bottleneck length and cavity volume of the gradient Helmholtz resonator array. The coiled structure of the gradient Helmholtz resonator array can increase the equivalent acoustic path in a limited space, but the complex folding path introduces additional end effects, bending effects, thermal viscosity losses, and processing sensitivity, making target frequency prediction difficult.

[0005] In summary, the design approach for gradient Helmholtz resonator arrays in related technologies suffers from drawbacks, including difficulty in simultaneously achieving low-frequency miniaturization, deterministic frequency prediction, and relatively low array design efficiency. Summary of the Invention This application proposes a gradient Helmholtz resonator array design method, array, and device based on a unified curled bottleneck, which can balance the enhancement of low-frequency acoustic signals and miniaturization of the curled structure, and improve the determinism of frequency prediction and array design efficiency.

[0006] The gradient Helmholtz resonator array design method based on a unified curled bottleneck according to the first aspect of this application includes the following steps: A set of target frequencies is determined based on the object to be enhanced, the set of target frequencies includes multiple target frequencies, and the target frequencies are determined by the characteristic frequencies of the object to be enhanced. The number of resonant groups in the gradient Helmholtz resonator array and the number of Helmholtz resonator units in each resonant group are determined according to the target frequency set and the preset grouping strategy to obtain the resonant group information; wherein, the grouping strategy is: the Helmholtz resonator units in each resonant group have the same curled bottleneck structure, and each Helmholtz resonator unit corresponds to a target frequency in the target frequency set. The curling bottleneck parameters for each of the resonant groups are determined based on the resonant group information and the preset processing strategy; The curling bottleneck parameters of each of the resonant groups are input into a preset curling bottleneck equivalent acoustic inertia model to obtain the equivalent acoustic inertia parameters of each of the resonant groups. The cavity height of each Helmholtz resonator unit is calculated based on the target frequency and the equivalent acoustic inertial parameters corresponding to each Helmholtz resonator unit. A gradient Helmholtz resonator array model is generated based on the resonator group information, the cavity height of each Helmholtz resonator unit, and the curling bottleneck parameter. The gradient Helmholtz resonator array model is used to indicate the structure of the gradient Helmholtz resonator array.

[0007] According to some embodiments of this application, after generating the gradient Helmholtz resonator array model based on the resonator group information, the cavity height of each Helmholtz resonator unit, and the curling bottleneck parameter, the method further includes: A corresponding frequency domain acoustic model is established based on the gradient Helmholtz resonant cavity array model. Simulations were performed based on the frequency domain acoustic model to obtain the peak resonant frequencies of each Helmholtz resonant cavity unit. The frequency error is obtained by comparing the peak resonant frequency of each Helmholtz resonant cavity unit with the target frequency. The cavity height is corrected based on the frequency error to obtain the corrected cavity height; A modified gradient Helmholtz resonator array model is generated based on the resonator group information, the modified cavity height of each Helmholtz resonator unit, and the curling bottleneck parameter.

[0008] According to some embodiments of this application, the step of correcting the cavity height based on the frequency error to obtain a corrected cavity height includes: The Helmholtz resonator unit with the smallest frequency error in each frequency group is used as the reference unit. The equivalent acoustic inertial correction parameters for each frequency group are calculated based on the reference unit. The cavity height of each Helmholtz resonator unit in the same group is recalculated based on the equivalent acoustic inertial correction parameters to obtain the corrected cavity height.

[0009] According to some embodiments of this application, the frequency domain acoustic model includes a two-dimensional pressure acoustic model and a three-dimensional pressure acoustic model. The step of establishing a corresponding frequency domain acoustic model based on the gradient Helmholtz resonator array model includes: Determine the array thickness direction of the gradient Helmholtz resonant cavity array model and generate the array thickness determination result; A corresponding frequency domain acoustic model is established based on the array thickness determination result; wherein... When the array thickness determination result indicates that the array thickness direction structure of the gradient Helmholtz resonant cavity array model is uniform, a two-dimensional pressure acoustic model is established. When the array thickness determination result indicates that there is a significant change in the array thickness direction of the gradient Helmholtz resonant cavity array model, a three-dimensional pressure acoustic model is established.

[0010] According to some embodiments of this application, after calculating the cavity height of each Helmholtz resonator unit based on the target frequency and the equivalent acoustic inertial parameters corresponding to each Helmholtz resonator unit, the method further includes: The cavity height is compared with a preset height threshold; If the cavity height is greater than the height threshold, the curling bottleneck parameter is adjusted.

[0011] According to some embodiments of this application, the equivalent acoustic inertial parameter is the equivalent inertial impedance coefficient. In the step of calculating the cavity height of each Helmholtz resonator unit based on the target frequency corresponding to each Helmholtz resonator unit and the equivalent acoustic inertial parameter, the formula for calculating the cavity height is: ; in, The height of the cavity, The equivalent inertial impedance is given by m, where m is the number of Helmholtz resonator elements. For the speed of sound, For the target frequency, t is the width of the air space within the cavity, and t is the inner radius.

[0012] According to the second aspect of this application, a gradient Helmholtz resonator array based on a unified curved bottleneck is provided. The gradient Helmholtz resonator array is fabricated based on a gradient Helmholtz resonator array model, which is obtained by the gradient Helmholtz resonator array design method based on a unified curved bottleneck as described in the first aspect of this application.

[0013] According to an acoustic device of a third aspect of this application, the acoustic device is provided with a gradient Helmholtz resonator array based on a unified curling bottleneck as described in the second aspect embodiment.

[0014] The gradient Helmholtz resonator array design method, array, and device based on a unified curled bottleneck according to embodiments of this application have at least the following beneficial effects: In this embodiment, a target frequency set is determined based on the object to be enhanced; the number of resonant groups in the gradient Helmholtz resonator array and the number of Helmholtz resonator units in each resonant group are determined based on the target frequency set and a preset grouping strategy, thus obtaining resonant group information; the curling bottleneck parameters of each resonant group are determined based on the resonant group information and a preset processing strategy; the curling bottleneck parameters of each resonant group are input into a preset curling bottleneck equivalent acoustic inertia model to obtain the equivalent acoustic inertial parameters of each resonant group; the cavity height of each Helmholtz resonator unit is calculated based on the target frequency and equivalent acoustic inertial parameters corresponding to each Helmholtz resonator unit; and a gradient Helmholtz resonator array model is generated based on the resonant group information, the cavity height of each Helmholtz resonator unit, and the curling bottleneck parameters. This application can balance the enhancement of low-frequency acoustic signals and miniaturization of the curled structure, improving the determinism of frequency prediction and the efficiency of array design.

[0015] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0016] The present application will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a flowchart of the gradient Helmholtz resonator array design method based on a unified curling bottleneck in the embodiments of this application; Figure 2 This is a cross-sectional view of a gradient Helmholtz resonant cavity array according to an embodiment of this application; Figure 3 This is a cross-sectional view of a gradient Helmholtz resonant cavity array according to an embodiment of this application. Detailed Implementation

[0017] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples.

[0018] In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, without necessarily requiring or implying any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0019] To address the problems of existing technologies, embodiments of this application provide a design method, array, and device for a gradient Helmholtz resonator array based on a unified curved bottleneck. The design method for a gradient Helmholtz resonator array based on a unified curved bottleneck, as provided in this application, will be described below.

[0020] Figure 1 This illustration shows a flowchart of a gradient Helmholtz resonator array design method based on a unified curved bottleneck, provided in an embodiment of this application. This method, applied to electronic devices, includes the following steps: S101. Determine the target frequency set based on the object to be enhanced. The target frequency set includes multiple target frequencies, and the target frequencies are determined by the characteristic frequencies of the object to be enhanced. S102. Determine the number of resonant groups in the gradient Helmholtz resonator array and the number of Helmholtz resonator units in each resonant group according to the target frequency set and the preset grouping strategy to obtain the resonant group information; wherein, the grouping strategy is: the Helmholtz resonator units in each resonant group have the same curled bottleneck structure, and each Helmholtz resonator unit corresponds to a target frequency in the target frequency set. S103. Determine the curling bottleneck parameters for each resonant group based on the resonant group information and the preset processing strategy. S104. Input the curling bottleneck parameters of each resonant group into the preset curling bottleneck equivalent acoustic inertia model to obtain the equivalent acoustic inertia parameters of each resonant group. S105. Calculate the cavity height of each Helmholtz resonator unit based on the target frequency and equivalent acoustic inertial parameters corresponding to each Helmholtz resonator unit. S106. Generate a gradient Helmholtz resonator array model based on the resonator group information, the cavity height of each Helmholtz resonator unit, and the curling bottleneck parameters. The gradient Helmholtz resonator array model is used to indicate the structure of the gradient Helmholtz resonator array.

[0021] In this embodiment, a target frequency set is determined based on the object to be enhanced; the number of resonant groups in the gradient Helmholtz resonator array and the number of Helmholtz resonator units under each resonant group are determined based on the target frequency set to obtain resonant group information; the curling bottleneck parameters of each resonant group are determined based on the resonant group information and a preset processing strategy; the curling bottleneck parameters of each resonant group are input into a preset curling bottleneck equivalent acoustic inertia model to obtain the equivalent acoustic inertial parameters of each resonant group; the cavity height of each Helmholtz resonator unit is calculated based on the target frequency and equivalent acoustic inertial parameters corresponding to each Helmholtz resonator unit; and a gradient Helmholtz resonator array model is generated based on the resonant group information, the cavity height of each Helmholtz resonator unit, and the curling bottleneck parameters. This application can balance the enhancement of low-frequency acoustic signals and miniaturization of the curled structure, improving the determinism of frequency prediction and the efficiency of array design.

[0022] In step S101 above, determining the target frequency set based on the object to be enhanced refers to determining the set of target frequencies based on the corresponding sound source of the acoustic signal to be enhanced. The target frequency refers to the frequency of the acoustic signal to be enhanced. Specifically, the target frequency can be determined by the acoustic signal spectrum of the object to be enhanced, mechanical structural parameters, operating speed range, fault characteristic frequency, sensor operating frequency band, etc. For example, for rotating machinery, the target frequency can be determined based on the number of gear teeth, meshing relationship, shaft rotation frequency, or fault harmonics. For ambient sound or equipment sound, the low-frequency peaks that need to be enhanced can be extracted from the measured spectrum.

[0023] For example, in scenarios involving the detection of weak low-frequency acoustic signals, such as non-contact fault diagnosis of rotating machinery and acoustic detection of long-range drones, it is necessary to focus on specific frequencies, such as fault characteristic frequencies and drone rotation frequencies, to determine the set of frequencies to be enhanced. As a set of target frequencies.

[0024] In step S102 above, determining the number of resonant groups in the gradient Helmholtz resonant cavity array based on the target frequency set refers to determining the number of Helmholtz resonant cavity units based on the target frequency. Each Helmholtz resonant cavity unit corresponds to a target frequency, and the number of resonant groups is determined based on the span of the target frequencies in the target frequency set.

[0025] It should be noted that if the target frequency range is small, the number of resonant groups is one, meaning all Helmholtz resonator units belong to the same resonant group and have the same curled bottleneck structure. When the target frequency range is large and a single curled bottleneck cannot cover the entire cavity height range, the Helmholtz resonator units are divided into multiple resonant groups, with the Helmholtz resonator units within the same group having the same curled bottleneck structure.

[0026] It should be noted that each Helmholtz resonator unit adopts the same or grouped curved bottleneck structure. The purpose is to make the units in the same group have the same or basically the same bottleneck equivalent acoustic inertia. Then, by changing the volume or height of the cavity at the rear end of each unit, different units have different Helmholtz resonant frequencies. Finally, multiple units are arranged spatially according to the target frequency from low to high, from high to low, or according to the sensor arrangement requirements to form a fixed gradient Helmholtz resonator array. The "unified curved bottleneck" in this application can refer to all units in the entire array using the same curved bottleneck (i.e., the number of resonator groups is equal to one), or it can refer to dividing the array into several groups according to the target frequency range (i.e., the number of resonator groups is greater than 1), with the same curved bottleneck used in the same group.

[0027] For example, if the target frequency range is large, such as a difference of 100Hz, all Helmholtz resonator units can be divided into low-frequency, mid-frequency, and high-frequency groups according to the target frequency, and a certain number of curled partitions can be selected for each group. However, the group still maintains a uniform curved bottleneck structure.

[0028] In step S103 above, determining the curvature bottleneck parameters for each resonator group based on the resonator group information and the preset processing strategy refers to determining the curvature bottleneck structural parameters according to the division of the Helmholtz resonator unit. The curvature bottleneck is formed by alternating partitions, folded channels, labyrinth channels, spiral channels, or other structures that can extend the sound propagation path. Taking an alternating partition type curvature channel as an example, the two sides of the structure are rigid walls, and the middle is an air domain; each partition extends into the air domain in the horizontal direction, and a lateral slit is formed between the free end of the partition and the opposite wall; the sound wave propagates along the slit and the folded channel, thereby forming a longer equivalent bottleneck within a limited structural height.

[0029] Figure 2This diagram shows a cross-sectional view of a gradient Helmholtz resonator array with a similar coiled bottleneck structure. Alternating partitions form the coiled bottleneck, with rigid vertical walls on both sides and an air domain in the middle. The lateral width is [missing information]. The length of each partition extending horizontally into the air space is... ( The vertical thickness of the partition is The vertical clearance between adjacent partitions is The baffle does not completely enclose the flow channel; a lateral slit is formed between the free end of the baffle and the opposite wall surface, the width of which is defined as... Each cavity has the same number of curled partitions. .

[0030] Specifically, in this embodiment, the number of curled partitions is determined by... The parameters for determining the curling bottleneck include array shape size limitations, processing methods, and processing accuracy. .in The number of curled partitions is generally taken as... ; This refers to the width of the air space within the cavity, specifically the width of the air space of the cavity unit. Since acoustic sensors need to be installed inside the cavity, therefore... It should be larger than the diameter of the acoustic sensor probe. This refers to the length of the rolled-up partition, i.e., the length of the rolled-up partition within the cavity. . The slit width, that is, the slit width between the free end of the partition and the opposite side wall, is therefore equal to... . The vertical clear spacing between adjacent partitions can be set to the same as... Consistency simplifies the design parameters. The thickness of the rolled partition is determined by the minimum wall thickness requirement of the processing method, with a reference value of 1mm.

[0031] The equivalent acoustic inertial parameter in step S104 above refers to the equivalent acoustic inertia. or equivalent inertia coefficient The curling bottleneck parameters of each resonator are input into a preset curling bottleneck equivalent acoustic inertia model to obtain the equivalent acoustic inertia parameters of each resonator. This refers to the equivalent acoustic inertia calculated based on the curling bottleneck parameters and the curling bottleneck equivalent acoustic inertia model. or equivalent inertia coefficient Since the curvature bottleneck parameters are the same for each group, each group has the same equivalent acoustic inertial parameters.

[0032] Specifically, this application equates the coiled bottleneck to a bottleneck section with a certain acoustic inertia. For a coiled bottleneck composed of multiple channels, its acoustic inertia can be calculated based on the geometric length and cross-sectional area of ​​each channel, and the acoustic inertia of each segment can be summed to obtain the equivalent acoustic inertia of the coiled bottleneck. For low-frequency operating conditions, the coiled bottleneck can be approximated as a one-dimensional equivalent acoustic channel. In the equivalent acoustic inertia model of the coiled bottleneck, the coiled bottleneck is mainly used to increase the equivalent bottleneck length or equivalent acoustic inertia, while the cavity mainly provides air compliance. The Helmholtz resonant frequency is determined by both the equivalent acoustic inertia of the coiled bottleneck and the cavity volume. The total inertial reactance of the coiled bottleneck needs to be calculated according to... The parity of each variable is discussed separately. The expression for the equivalent acoustic inertia model of the curled bottleneck is as follows: ; in, These are the cross-sectional areas of the vertical segments that are away from / close to the axis of rotation, respectively, used to calculate the acoustic inertia of the vertical segments; air density, Let t be the speed of sound, and t be the inner radius, which is the distance from the side of the cavity closest to the axis of rotation to the axis of rotation. This represents the thickness of the partition.

[0033] Let the quantity determined by the geometric parameters in the above formula, i.e., the expression within the parentheses, be denoted as: Then the total inertial resistance of the coiled bottleneck can be uniformly expressed as ; Therefore, the equivalent inertial resistance coefficient C can be calculated based on the bottleneck parameters, and thus the equivalent acoustic inertia can be calculated. .

[0034] In step S105 above, calculating the cavity height of each Helmholtz resonator unit based on its target frequency and equivalent acoustic inertial parameters refers to calculating the cavity height of the resonator based on the target frequency and equivalent inertial coefficient C of each cavity unit. .

[0035] Specifically, since the units in the same group use a uniform curved bottleneck, their equivalent acoustic inertia is the same or basically the same. Therefore, the difference in resonant frequency between different units within the same group is mainly determined by the cavity volume. Since other geometric parameters are already determined, the cavity volume is determined by the cavity height. This application calculates the cavity height corresponding to each target frequency based on the Helmholtz resonance relationship. The calculation formula is: ; in, For the first Target frequency The corresponding cavity height.

[0036] In step S106 above, a gradient Helmholtz resonator array model is generated based on the resonator group information, the cavity height of each Helmholtz resonator unit, and the curvature bottleneck parameter. The geometric structure of each Helmholtz resonator unit can be obtained based on the cavity height and curvature bottleneck parameter. Then, combined with the resonator group information, the structure of the entire gradient Helmholtz resonator array can be obtained. Therefore, firstly, based on the grouping and number of each Helmholtz resonator unit, the cavity height of each Helmholtz resonator unit, and the previously obtained curvature bottleneck parameter, the relative positions of each Helmholtz resonator unit are determined. Then, based on the relative positions, a gradient Helmholtz resonator array model corresponding to the gradient Helmholtz resonator array structure is generated.

[0037] It should be noted that, firstly, the relative positions of each Helmholtz resonator unit are determined based on the resonator group information and the cavity height; that is, the distance between the inner wall of each cavity unit and the rotation axis, as well as the arrangement of the cavities, are determined. Different target frequencies are then determined through the rear cavity height. Changes obtained, cavity height The higher the cavity, the lower the resonant frequency. To reduce manufacturing costs, this embodiment places the Helmholtz resonant cavity unit with the highest cavity height at the center of the array. The cavity frequency distribution gradually increases from the inside to the outside, and the cavity height shows a decreasing gradient trend. The resonant frequency of the cavity unit closest to the central axis is the minimum value of the target frequency. Let the distance from the m-th cavity's side closest to the rotation axis to the rotation axis be... The wall thickness of the adjacent cavities is The position of each cavity unit can be determined by the following formula, as follows: .

[0038] This application sets up multiple Helmholtz resonant cavity units in an array. Each resonant cavity unit adopts the same or grouped curved bottleneck structure, so that the units in the same group have the same or basically the same bottleneck acoustic inertia; then, by changing the volume or height of the cavity at the rear end of each unit, different units have different Helmholtz resonant frequencies; finally, the multiple units are spatially arranged according to the target frequency from low to high or from high to low to form a fixed gradient Helmholtz resonant cavity array.

[0039] This application no longer allows each array unit to obtain different frequencies through different curling paths. Instead, it uses the same or essentially the same curling bottleneck structure for the resonant cavity units within the same array or frequency group. The curling bottleneck primarily serves to "uniformly increase the equivalent acoustic inertia." Different target frequencies are achieved mainly through gradient changes in the volume or height of the rear cavity. This approach retains the advantages of low-frequency miniaturization of the curling structure while improving the determinism of frequency prediction and the efficiency of array design.

[0040] In some implementations, after generating a gradient Helmholtz resonator array model based on the resonator group information, the cavity height of each Helmholtz resonator unit, and the curling bottleneck parameter, the following may also be included: A corresponding frequency domain acoustic model is established based on the gradient Helmholtz resonant cavity array model. Simulations were performed using a frequency domain acoustic model to obtain the peak resonant frequencies of each Helmholtz resonator unit. The frequency error is obtained by comparing the peak resonant frequency of each Helmholtz resonant cavity unit with the target frequency. The cavity height is corrected based on the frequency error to obtain the corrected cavity height; A modified gradient Helmholtz resonator array model is generated based on the resonator group information, the modified cavity height of each Helmholtz resonator unit, and the curling bottleneck parameters.

[0041] In this embodiment, a corresponding frequency domain acoustic model is first established based on the gradient Helmholtz resonator array model. Simulations are then performed using this model to obtain the peak resonant frequency of each Helmholtz resonator unit. The peak resonant frequency of each unit is compared with the target frequency to obtain the frequency error. The cavity height is then corrected based on this error to obtain the corrected cavity height. Finally, a corrected gradient Helmholtz resonator array model is generated based on the resonator group information, the corrected cavity height of each unit, and the curvature bottleneck parameters. This further improves the determinism of frequency prediction.

[0042] The above-mentioned establishment of the corresponding frequency domain acoustic model based on the gradient Helmholtz resonator array model refers to the construction of a frequency domain acoustic model in COMSOL Multiphysics or other acoustic finite element software based on the gradient Helmholtz resonator array model obtained in step S106 for finite element simulation.

[0043] The above simulation based on the frequency domain acoustic model, obtaining the peak resonant frequency of each Helmholtz resonator unit, refers to verifying the array's frequency response through finite element simulation to obtain the peak resonant frequency of each Helmholtz resonator unit. .

[0044] The above comparison of the peak resonant frequency of each Helmholtz resonator unit with the target frequency to obtain the frequency error refers to the calculation of the frequency error. .

[0045] The above-mentioned correction of the cavity height based on frequency error to obtain the corrected cavity height refers to first adjusting the frequency error of each cavity unit. Deviation threshold from allowable frequency Compare all units If the theoretical design meets the requirements, then the cavity height is corrected. If some units have a system deviation in the same direction or exceed the threshold, then the cavity height error is corrected to obtain the corrected cavity height.

[0046] The above-mentioned generation of the modified gradient Helmholtz resonator array model based on the resonator group information, the modified cavity height of each Helmholtz resonator unit, and the curling bottleneck parameter refers to modifying the model obtained in step S106 according to the modified cavity height to generate a new model.

[0047] It should be noted that the corrected cavity height is re-substituted into the array model, and a second finite element frequency sweep is performed to compare the deviation between the corrected peak frequency and the target frequency. If the deviation meets the threshold, the final structure is determined; if it still exceeds the threshold, the error is corrected again based on the source of the deviation.

[0048] The following is a detailed example of a simulation process: Geometric modeling is performed using simulation software: a two-dimensional or three-dimensional frequency domain acoustic model is established.

[0049] Material settings: Set the air zone to ambient temperature air, and input the density. and speed of sound The solid wall has a much larger impedance than air, so it is set as an acoustically hard boundary. If structural vibration coupling needs to be considered, a solid mechanics module is added and the material elastic parameters are set.

[0050] Physics selection: For preliminary verification where the channel size is significantly larger than the thickness of the thermoviscous boundary layer, the "Pressure Acoustics, Frequency Domain" module can be used.

[0051] Boundary conditions: A plane wave radiation or background pressure field is set at the array inlet, and the incident sound pressure amplitude can be set to 1 Pa for easy normalization later; an acoustic hard boundary is set on the outer wall; a radiation boundary, a plane wave radiation boundary, or a perfectly matched layer is set at the open end to reduce reflection.

[0052] Frequency sweep settings: The sweep range should cover all target frequencies, with finer sweeps near the target frequencies. For example, if the target frequency is 252 Hz to 588 Hz, a frequency sweep of 200 Hz to 650 Hz can be set with a step size of 1 Hz. If more precise peak values ​​are required, a local fine sweep of 0.2 Hz or 0.5 Hz can be used near each peak value.

[0053] Mesh generation: The largest cell size in the air domain is generally no larger than 1 / 6 to 1 / 10 of the shortest wavelength; local densification is required at slits, foldback ends, and bottlenecks.

[0054] Result Extraction: Point probes, average pressure probes, or integration operators are placed in each cavity to extract the sound pressure-frequency curve. The peak resonant frequency of each cavity is then obtained. .

[0055] Judgment criteria: Calculation If all units If the theoretical design meets the requirements, then the error correction is performed if some units have a systematic deviation in the same direction or exceed the threshold.

[0056] In some implementations, the cavity height is corrected based on the frequency error to obtain a corrected cavity height, which may include: The Helmholtz resonator unit with the smallest frequency error in each frequency group is used as the reference unit. The equivalent acoustic inertial correction parameters for each frequency group are calculated based on the reference unit. The cavity height of each Helmholtz resonator unit in the same group is recalculated based on the equivalent acoustic inertial correction parameters to obtain the corrected cavity height.

[0057] In this embodiment, the Helmholtz resonator unit with the smallest frequency error in each frequency group is first used as the reference unit. Then, the equivalent acoustic inertial correction parameters for each frequency group are calculated based on the reference unit. Next, the cavity height of each Helmholtz resonator unit in the same group is recalculated based on the equivalent acoustic inertial correction parameters to obtain the corrected cavity height. By using the reference unit to back-calculate the corrected equivalent acoustic inertial correction parameters and extending them to other units in the same group, the workload of calibrating each unit individually can be reduced, further improving the array design efficiency.

[0058] Specifically, taking the equivalent inertia coefficient as an example, if multiple units of the same group of uniformly curled bottlenecks exhibit frequency deviations in the same direction—for example, if the simulated peak value is generally higher or lower than the theoretical value—then the deviation can be considered to mainly originate from the estimation error of the equivalent acoustic inertia of the curled bottleneck, insufficient end correction, additional inertia due to bending, thermal viscosity effects, or processing boundary deviations. In this case, it is not necessary to re-trial and error unit by unit. Instead, a reference unit is selected, and the measured or simulated peak frequency is substituted into the back calculation to obtain the corrected equivalent inertia coefficient. .

[0059] If the height of the reference unit cavity is Its simulation or test capture frequency is Then the correction factor can be calculated using the following formula: ; Then Substituting the values ​​into the cavity height calculation formula for all units in the same group, we obtain the corrected cavity height: ; It should be noted that if the error manifests as inconsistent deviation directions at different frequency points within a group, it indicates that a single uniform correction coefficient is insufficient to describe all deviations. It is necessary to check the coupling between units, cavity spacing, boundary reflection, or local mesh accuracy, and group correction, secondary fitting correction, or readjustment of the curling bottleneck parameters can be used.

[0060] In some implementations, the frequency domain acoustic model includes a two-dimensional pressure acoustic model and a three-dimensional pressure acoustic model. The corresponding frequency domain acoustic model, established based on the gradient Helmholtz resonator array model, may include: Determine the array thickness direction of the gradient Helmholtz resonator array model and generate the array thickness determination result; A corresponding frequency domain acoustic model is established based on the array thickness determination results; among which... Under the condition that the array thickness direction structure of the gradient Helmholtz resonant cavity array model is uniform as indicated by the array thickness judgment result, a two-dimensional pressure acoustic model is established. When the array thickness judgment result indicates that there is a significant change in the array thickness direction of the gradient Helmholtz resonant cavity array model, a three-dimensional pressure acoustic model is established.

[0061] In this embodiment, the array thickness direction of the gradient Helmholtz resonator array model is first determined, generating an array thickness determination result. Then, a corresponding frequency domain acoustic model is established based on the array thickness determination result. This can further improve array design efficiency.

[0062] Specifically, if the array has a uniform structure in the thickness direction, a two-dimensional pressure acoustic model is established to improve computational efficiency; if there are significant changes in the thickness direction or the actual sensor position needs to be considered, a three-dimensional pressure model is established.

[0063] In some implementations, after calculating the cavity height of each Helmholtz resonator unit based on the target frequency and equivalent acoustic inertial parameters corresponding to each Helmholtz resonator unit, the following may also be included: Compare the cavity height with a preset height threshold; When the cavity height exceeds the height threshold, the curling bottleneck parameters are adjusted.

[0064] In this embodiment, the cavity height is first compared with a preset height threshold. Then, if the cavity height is greater than the height threshold, the curling bottleneck parameter is adjusted. This avoids the cavity height exceeding or falling below the actual processing threshold, ensuring the designed array is manufacturable and further improving array design efficiency.

[0065] Specifically, after calculating the cavity height... Next, a manufacturability check is performed: if the height of a certain cavity is... Greater than the height threshold This can increase the width of the air domain. Length of the curled partition Number of curls Or reduce the spacing between the partitions If the height of a certain cavity If the size is too small, it will cause processing difficulties, or the cavity damping will be too large, so the number of coils can be reduced. Increase the spacing between partitions Or adjust the grouping range.

[0066] In some implementations, the equivalent acoustic inertial parameter is the equivalent inertial impedance coefficient. In the step of calculating the cavity height of each Helmholtz resonator unit based on the target frequency and equivalent acoustic inertial parameter corresponding to each Helmholtz resonator unit, the formula for calculating the cavity height is: ; in, The height of the cavity, The equivalent inertial impedance is given by m, where m is the number of Helmholtz resonator elements. For the speed of sound, For the target frequency, t is the width of the air space within the cavity, and t is the inner radius.

[0067] In this embodiment, the cavity height of each Helmholtz resonator unit can be calculated quickly and accurately according to the above formula.

[0068] In summary, this application introduces a coiled bottleneck in each Helmholtz resonator unit, allowing sound waves to experience a longer equivalent propagation path within a limited space, thereby increasing the bottleneck's equivalent acoustic inertia. Therefore, with the same external dimensions, this invention can achieve a lower resonant frequency than a conventional straight-bottom Helmholtz resonator, addressing the problem of excessively large structural dimensions when enhancing low-frequency acoustic signals.

[0069] This application enables units within the same array or frequency group to use a uniform coiled bottleneck, rather than obtaining different frequencies by changing the number of coils or the folding path of each unit. In this way, the equivalent acoustic inertia of the bottleneck sections of each unit is the same or substantially the same, and the frequency difference is mainly determined by the cavity volume, making the correspondence between the target frequency and the cavity height clearer.

[0070] This application uses a well-defined physical model of a Helmholtz resonator for frequency design, allowing for the determination of the target frequency before deriving the required cavity volume for each element. Compared to coiled gradient superstructures, which primarily rely on iterative finite element trial and error, this approach offers higher design efficiency and greater interpretability.

[0071] This application establishes a unified error correction method. For systematic deviations caused by end effects, bending effects, thermal adhesion effects, or processing errors, the corrected equivalent inertial resistance coefficient can be calculated using a reference element and extended to other elements in the same group, reducing the workload of calibrating each element individually.

[0072] This application enables the arrangement of multiple resonant cavity units with different target frequencies in the same array. When the incident acoustic signal simultaneously contains multiple low-frequency components, each frequency component can generate local enhancement in its corresponding unit, achieving synchronous enhancement and spatial separation of multiple frequency points within the low-frequency band.

[0073] This application is suitable for detecting weak acoustic signals. The acoustic energy near the target frequency can be locally amplified in the corresponding cavity. The sensor can be placed at the array exit, near the array near field, or near a specific cavity, thereby increasing the amplitude of the target frequency component before acquisition and providing higher quality input for subsequent spectrum analysis, fault diagnosis, or signal recognition.

[0074] This application has good scalability. By changing the target frequency set, the number of elements, the cavity volume gradient, the array arrangement, or the unified coiling bottleneck parameters, it can be adapted to different low-frequency bands and different application scenarios.

[0075] The design process of this application is explained in detail below, taking the acoustic signal enhancement of a broken tooth fault in a gear reducer as an example: Acoustic signal detection of broken teeth in planetary gear reducers requires attention to the meshing frequency. Based on gear parameters and input speed, the meshing frequency to be enhanced ranges from 252 Hz to 588 Hz. A coiled bottleneck gradient Helmholtz resonator array is designed for enhancing the aforementioned low-frequency characteristic acoustic signals. This array comprises nine Helmholtz resonator units, with target frequencies corresponding to the meshing frequencies under different operating conditions, as shown in Table 1. Table 1. Target Frequency for Acoustic Enhancement of Gear Gear Breakage Faults

[0076] like Figure 3 As shown, in this embodiment, the nine target frequencies are divided into three groups: 252 Hz, 294 Hz, and 336 Hz correspond to the low-frequency group, with the number of curled bottlenecks (n) set to 8; 378 Hz, 420 Hz, and 462 Hz correspond to the mid-frequency group, with n set to 7; and 504 Hz, 546 Hz, and 588 Hz correspond to the high-frequency group, with n set to 6. Each group uses the same curled bottleneck, and different resonant frequencies within the same group are achieved by changing the cavity height.

[0077] In the specific design process, the channel width of each group is first determined based on the processing dimensions. partition thickness partition length Vertical clearance between adjacent partitions and lateral slit width Then calculate C for each group according to S3; then substitute the target frequency in Table 1 into the cavity height formula in S3 to obtain the cavity height of each unit. As shown in Table 2: Table 2. Record of Cavity Height Calculation and Simulation Correction

[0078] When establishing the acoustic frequency domain simulation model of this array in COMSOL Multiphysics, the following procedure can be followed: First, establish the array geometry based on the target frequency and the curling bottleneck parameters in Table 2; second, set the solid boundary as an acoustic hard boundary and the air domain as room temperature air; third, apply a 1 Pa plane wave incident or background pressure field at the array inlet and set a perfectly matched layer at the outlet; fourth, set a sweep frequency range of 200 Hz to 650 Hz with a step size of 1 Hz; fifth, set a pressure probe in each cavity; sixth, calculate the frequency response curve of each cavity.

[0079] After the simulation, the peak frequency of the sound pressure level was extracted for each unit. As shown in Table 2, the peak frequencies of cavities 1 and 2 differed from the theoretical target value by approximately 1 Hz, indicating that their initial predictions met the threshold requirements. However, the deviation of cavity 3 exceeded 2 Hz, so this type of constriction can be corrected. The deviations of cavities 4-6 were all equal to the threshold and did not require correction. The peak frequencies of cavities 7 to 9 differed from the theoretical target value by approximately 3 Hz. Therefore, one unit in the high-frequency group was selected as the reference unit, and the high-frequency group correction coefficient C′ was calculated using S6. The cavity height of the high-frequency group was then recalculated. After correction, the simulation was repeated, and the peak deviations near each target frequency were all controlled below 1 Hz, indicating that the unified correction method was effective.

[0080] This application also relates to a gradient Helmholtz resonator array based on a unified curled bottleneck. The gradient Helmholtz resonator array is fabricated according to a gradient Helmholtz resonator array model, which is obtained through the gradient Helmholtz resonator array design method based on a unified curled bottleneck described in the above embodiments.

[0081] Specifically, this application employs a gradient Helmholtz resonator array structure with a unified or grouped uniformly curled bottleneck, allowing the curled bottleneck to primarily serve the function of "uniformly increasing the equivalent acoustic inertia"; different target frequencies are mainly achieved through gradient changes in the volume or height of the rear cavity. This approach retains the low-frequency miniaturization advantages of the curled structure while improving the determinism of frequency prediction and the efficiency of array design.

[0082] It should be noted that, in addition to the gradient Helmholtz resonator array in this application, Figure 2 and Figure 3 In addition to the cylindrical Helmholtz resonant array shown, rectangular or other shapes can also be used.

[0083] This application also relates to an acoustic device in which a gradient Helmholtz resonator array based on a unified curling bottleneck, as described in the above embodiments, is disposed.

[0084] Specifically, acoustic equipment can be related to the detection of weak sound signals, such as acoustic signal detection equipment for broken tooth faults.

[0085] It should be clarified that this application is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of this application is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of this application.

[0086] The functional blocks shown in the above-described structural diagram can be implemented as hardware, software, firmware, or a combination thereof. When implemented in hardware, they can be, for example, electronic circuits, application-specific integrated circuits (ASICs), appropriate firmware, plug-ins, function cards, etc. When implemented in software, the elements of this application are programs or code segments used to perform the required tasks. Programs or code segments can be stored on a machine-readable medium or transmitted over a transmission medium or communication link via data signals carried on a carrier wave. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, fiber optic media, radio frequency (RF) links, etc. Code segments can be downloaded via computer networks such as the Internet, intranets, etc.

[0087] It should also be noted that the exemplary embodiments mentioned in this application describe methods or systems based on a series of steps or apparatus. However, this application is not limited to the order of the above steps; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0088] The aspects of this disclosure have been described above with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this disclosure. It should be understood that each block in the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that these instructions, executable via the processor of the computer or other programmable data processing apparatus, enable the implementation of the functions / actions specified in one or more blocks of the flowchart illustrations and / or block diagrams. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field-programmable logic circuit. It is also understood that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can also be implemented by special-purpose hardware performing the specified functions or actions, or can be implemented by a combination of special-purpose hardware and computer instructions.

[0089] The above description is merely a specific implementation of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. A design method for a gradient Helmholtz resonator array based on a unified curled bottleneck, characterized in that, Includes the following steps: A set of target frequencies is determined based on the object to be enhanced, the set of target frequencies includes multiple target frequencies, and the target frequencies are determined by the characteristic frequencies of the object to be enhanced. The number of resonant groups in the gradient Helmholtz resonator array and the number of Helmholtz resonator units in each resonant group are determined according to the target frequency set and the preset grouping strategy to obtain the resonant group information; wherein, the grouping strategy is: the Helmholtz resonator units in each resonant group have the same curled bottleneck structure, and each Helmholtz resonator unit corresponds to a target frequency in the target frequency set. The curling bottleneck parameters for each of the resonant groups are determined based on the resonant group information and the preset processing strategy; The curling bottleneck parameters of each of the resonant groups are input into a preset curling bottleneck equivalent acoustic inertia model to obtain the equivalent acoustic inertia parameters of each of the resonant groups. The cavity height of each Helmholtz resonator unit is calculated based on the target frequency and the equivalent acoustic inertial parameters corresponding to each Helmholtz resonator unit. A gradient Helmholtz resonator array model is generated based on the resonator group information, the cavity height of each Helmholtz resonator unit, and the curling bottleneck parameter. The gradient Helmholtz resonator array model is used to indicate the structure of the gradient Helmholtz resonator array.

2. The gradient Helmholtz resonator array design method based on a unified curled bottleneck according to claim 1, characterized in that, After generating the gradient Helmholtz resonator array model based on the resonator group information, the cavity height of each Helmholtz resonator unit, and the curling bottleneck parameter, the method further includes: A corresponding frequency domain acoustic model is established based on the gradient Helmholtz resonant cavity array model. Simulations were performed based on the frequency domain acoustic model to obtain the peak resonant frequencies of each Helmholtz resonant cavity unit. The frequency error is obtained by comparing the peak resonant frequency of each Helmholtz resonant cavity unit with the target frequency. The cavity height is corrected based on the frequency error to obtain the corrected cavity height; A modified gradient Helmholtz resonator array model is generated based on the resonator group information, the modified cavity height of each Helmholtz resonator unit, and the curling bottleneck parameter.

3. The gradient Helmholtz resonator array design method based on a unified curled bottleneck according to claim 2, characterized in that, The step of correcting the cavity height based on the frequency error to obtain the corrected cavity height includes: The Helmholtz resonator unit with the smallest frequency error in each frequency group is used as the reference unit. The equivalent acoustic inertial correction parameters for each frequency group are calculated based on the reference unit. The cavity height of each Helmholtz resonator unit in the same group is recalculated based on the equivalent acoustic inertial correction parameters to obtain the corrected cavity height.

4. The gradient Helmholtz resonator array design method based on a unified curled bottleneck according to claim 2, characterized in that, The frequency domain acoustic model includes a two-dimensional pressure acoustic model and a three-dimensional pressure acoustic model. The step of establishing the corresponding frequency domain acoustic model based on the gradient Helmholtz resonator array model includes: Determine the array thickness direction of the gradient Helmholtz resonant cavity array model and generate the array thickness determination result; A corresponding frequency domain acoustic model is established based on the array thickness determination result; wherein... When the array thickness determination result indicates that the array thickness direction structure of the gradient Helmholtz resonant cavity array model is uniform, a two-dimensional pressure acoustic model is established. When the array thickness determination result indicates that there is a significant change in the array thickness direction of the gradient Helmholtz resonant cavity array model, a three-dimensional pressure acoustic model is established.

5. The gradient Helmholtz resonator array design method based on a unified curled bottleneck according to claim 1, characterized in that, After calculating the cavity height of each Helmholtz resonator unit based on the target frequency and the equivalent acoustic inertial parameters corresponding to each Helmholtz resonator unit, the method further includes: The cavity height is compared with a preset height threshold; If the cavity height is greater than the height threshold, the curling bottleneck parameter is adjusted.

6. The gradient Helmholtz resonator array design method based on a unified curled bottleneck according to claim 1, characterized in that, The equivalent acoustic inertial parameter is the equivalent inertial impedance coefficient. In the step of calculating the cavity height of each Helmholtz resonator unit based on the target frequency and the equivalent acoustic inertial parameter corresponding to each Helmholtz resonator unit, the formula for calculating the cavity height is: ； in, The height of the cavity, The inertial impedance is the equivalent inertial impedance, and m is the number of Helmholtz resonator elements. For the speed of sound, For the target frequency, t is the width of the air space within the cavity, and t is the inner radius.

7. A gradient Helmholtz resonator array based on a unified curled bottleneck, characterized in that, The gradient Helmholtz resonator array is fabricated based on the gradient Helmholtz resonator array model, which is obtained by the gradient Helmholtz resonator array design method based on the unified curling bottleneck as described in any one of claims 1 to 6.

8. An acoustic device, characterized in that, The acoustic device is equipped with the gradient Helmholtz resonator array based on a unified curling bottleneck as described in claim 7.

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