Panel Duct Resonator Layout for Broadband Noise Absorption

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Solution Overview

Problem

Existing acoustic resonators fail to provide broadband acoustic absorption and are challenging to attach and support around ducts, leading to undesirable noise from air flow through panel openings.

Innovation Solution

A sound absorbing device with a panel, duct, and embedded quarter-wavelength acoustic resonators that absorb a broad range of frequencies by varying resonator lengths and configurations, including subsets extending from multiple planar sides of the duct.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If acoustic resonators are used for acoustic absorption, then acoustic noise at specific frequency range is absorbed, but broadband acoustic absorption is not provided and attachment and support of multiple acoustic resonators around duct is problematic

Engineering Contradiction:

Improveacoustic noiseVSAvoidbroadband acoustic absorption

Core Design Contradiction:

Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The acoustic resonator is segmented into multiple independent resonant elements (first, second, third, and fourth acoustic resonators) with different lengths. Each resonator targets a specific frequency range, and collectively they provide broadband acoustic absorption. The resonators are positioned at different locations around the duct to handle noise from various directions and frequency ranges.

Inventive Principle:

Principle #1Segmentation

2Object-affected harmful factors

If acoustic resonators are used for acoustic absorption, then acoustic noise at specific frequency range is absorbed, but attachment and support of multiple acoustic resonators around duct is problematic

Engineering Contradiction:

Improveacoustic noiseVSAvoidattachment and support of multiple acoustic resonators

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

Multiple acoustic resonators are merged into a single integrated device structure. The resonators are combined with the duct to form a unified assembly where the resonators extend into the duct from different sides. This integration eliminates the need for separate attachment mechanisms for each resonator, simplifying the support structure while maintaining broadband acoustic absorption capability.

Inventive Principle:

Principle #5Merging (Combining)

3Speed

If air flows through duct at different velocities, then air flow requirement is met, but acoustic noise resulting from frequencies outside specific frequency range is not absorbed

Engineering Contradiction:

Improveair flow velocityVSAvoidacoustic noise

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

Different sections of the acoustic absorption device have different resonator configurations optimized for local conditions. The resonators have varying lengths and are positioned at different locations around the duct, creating local variations in acoustic absorption characteristics. This allows the device to effectively absorb acoustic noise across a broad frequency range while accommodating varying air flow velocities through the duct.

Inventive Principle:

Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The device effectively suppresses acoustic noise across a wide frequency range by using quarter-wavelength resonators with varying lengths, providing efficient broadband suppression.

Implementation Method 1

An acoustic resonator, e.g., a Helmholtz resonator or a quarter-wavelength tube, can be used for acoustic absorption of a specific frequency range

Methodology Applied

Scientific EffectAcoustic resonance: Resonance

Implementation Method 2

The plurality of acoustic resonators can include a first subset of quarter-wavelength acoustic resonators extending from a first planar side of the duct

Methodology Applied

Scientific EffectAcoustic absorption: Acoustic Absorption

Data Source

PatentUS12597408B2Sound absorbing devices for panels with openings

Publication Date: 2026.04.07 TOYOTA JIDOSHA KK

AI summary

A sound absorbing device includes a panel with an opening, a duct extending from the panel and in fluid communication with the opening, and a plurality of acoustic resonators embedded in the panel and in fluid communication with the duct. The duct can have a rectangular cuboid shape and the plurality of acoustic resonators can include a first subset of quarter-wavelength tubes extending from a first planar side of the duct, a second subset of quarter-wavelength tubes extending from a second planar side of the duct, a third subset of quarter-wavelength tubes extending from a third planar side of the duct, and a fourth subset of quarter-wavelength tubes extending from a fourth planar side of the duct. Also, the second subset of quarter-wavelength tubes and the fourth subset of quarter-wavelength tubes can have mirror symmetry with the first subset of quarter-wavelength tubes and the third subset of quarter-wavelength tubes, respectively.