Acoustic Panel Rounded Particle Septum Linear Resistance
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Solution Overview
Problem
Existing acoustic panels with honeycomb cores and septum layers face challenges in achieving uniform noise attenuation across a wide frequency band due to high non-linearity issues, particularly when using woven meshes or laser-drilled films, which are time-consuming to install and can cause backpressure at high velocities.
Innovation Solution
The use of rounded particles, such as spheres or ellipsoids, poured into the core cells and bonded to form a septum layer, providing substantially linear acoustic resistance, along with a system and method for positioning, metering, and vibrating these particles to achieve efficient packing and adhesion, eliminating the need for mechanical insertion and vapor degreasing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If woven meshes are used as septum layers, then acceptable non-linearity factors are achieved, but mechanical insertion and positioning is time-consuming
Solution Approach 1:
The invention changes the physical form of the septum layer from continuous woven mesh to discrete rounded particles. This parameter change allows the particles to be poured into cells rather than mechanically inserted, dramatically reducing installation time while maintaining acceptable non-linearity factors through proper particle selection and packing
Solution Approach 2:
The invention replaces the mechanical insertion process required for woven meshes with a gravity-based pouring process for rounded particles. This substitution eliminates complex positioning operations and reduces installation time significantly while achieving comparable acoustic performance
2Ease of manufacture
If laser-drilled films are used as septum layers, then installation is simplified, but square entrances cause separation at high velocities and create high backpressure
Solution Approach 1:
The invention replaces the square entrances of laser-drilled films with rounded particle surfaces. The curved geometry of rounded particles creates smooth flow paths that prevent separation at high velocities, reducing backpressure while maintaining ease of installation through pouring
Solution Approach 2:
The invention uses rounded particles packed to form a porous septum layer with interconnected voids. This porous structure provides tortuous flow paths that maintain low backpressure across a wide range of velocities, eliminating the separation issue associated with square entrances
3Adaptability or versatility
If honeycomb core cells are divided into multiple chambers, then noise attenuation over wider frequency band is achieved, but device complexity increases
Solution Approach 1:
The invention divides honeycomb core cells into multiple chambers using rounded particles that form natural separators. This segmentation creates multiple resonant frequencies within each cell, broadening the noise attenuation frequency range while the particle-based approach keeps the implementation simple and scalable
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
This approach results in a more efficient and cost-effective acoustic panel with reduced non-linearity, enabling effective noise attenuation across a broader frequency range without the limitations of prior art materials and installation methods.
Implementation Method 1
The vibratory base may be configured to vibrate the rounded particles in each cell in order to pack them more tightly
Implementation Method 2
a septum layer including a plurality of rounded particles located at a particular depth in each cell, and providing substantially linear acoustic resistance to a sound wave entering the cell
Data Source
AI summary
An acoustic panel for attenuating sound, and a system and method for making the acoustic panel. The acoustic panel employs rounded particles which are introduced into the cells of a core and fixed at a particular depth to form a septum layer providing substantially linear acoustic resistance to sound waves entering the cell. The particles may be between 100 microns and 700 microns in diameter, may be solid or hollow, may have smooth or textured surfaces, and/or may be made of syntactic foam or glass or ceramic. The system includes a positioning mechanism for positioning the particles at the particular depth, metering and gating mechanisms for introducing a metered amount of the particles into each cell, and a vibratory base for vibrating the particles to better pack them. Once the particles are in the cells, the septum layer is fixed, and the positioning mechanism is removed.