Sound Absorbing Sheet With Micro Resonant Structure
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Solution Overview
Problem
Existing sound absorbing materials, such as non-woven fabrics, are ineffective in mid and low frequency bands due to their porous structure, which is advantageous for high frequency sound absorption but poor in lower frequency ranges.
Innovation Solution
A sound absorbing sheet with a micro resonant structure is created by forming convex-concave patterns on a porous substrate, where the area ratio of depressions ranges from 40% to 99%, resulting in lower air permeability in the depressed regions compared to the protruded regions, enhancing sound absorption in mid and low frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If porous materials are used for sound absorption, then high frequency sound absorption is improved, but mid and low frequency sound absorption deteriorates
Solution Approach 1:
The invention applies local quality by creating regions with different properties on the porous substrate surface. Specifically, it forms convex-concave patterns where depression regions have different air permeability characteristics compared to protrusion regions. This local differentiation enables the material to handle different frequency ranges through different mechanisms: porous absorption for high frequencies and resonant absorption for mid-low frequencies.
Solution Approach 2:
The invention effectively creates a composite structure by combining a porous substrate with a micro resonant structure formed through thermal transfer. The resulting material integrates two different sound absorption mechanisms: the porous structure for high frequency absorption and the convex-concave resonant structure for mid-low frequency absorption, achieving broad-spectrum sound absorption capability.
2Reliability
If material thickness is increased to improve sound absorption, then sound absorption capability is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
Instead of increasing thickness in the vertical dimension, the invention introduces structural complexity in the surface dimension by forming convex-concave patterns. This dimensional shift allows the material to achieve enhanced sound absorption across multiple frequency ranges without increasing overall thickness, thereby avoiding the associated manufacturing and structural complexity issues.
Solution Approach 2:
The invention replaces the traditional approach of using thick porous materials (mechanical volume-based absorption) with a surface-based resonant structure. By substituting the volume-dependent porous absorption mechanism with a surface resonant mechanism, the material achieves improved mid-low frequency absorption without requiring increased thickness, thus simplifying the overall material structure and manufacturing process.
3Ease of manufacture
If conventional non-woven fabrics are used, then manufacturing simplicity is maintained, but sound absorption in mid and low frequency bands deteriorates
Solution Approach 1:
The invention applies preliminary action by incorporating the convex-concave pattern formation directly into the manufacturing process through thermal transfer during or after non-woven fabric production. This preliminary structuring of the surface geometry enables the material to gain resonant absorption capabilities without requiring separate post-processing steps, thus maintaining manufacturing simplicity while dramatically improving mid-low frequency sound absorption performance.
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 micro resonant structure improves sound absorption capabilities in the 200 Hz to 2000 Hz frequency range, achieving an average coefficient of sound absorption of 0.4 or more, effectively addressing the limitations of existing materials in mid and low frequency bands.
Implementation Method 1
the sound absorbing sheet includes a micro resonant structure on the porous substrate and thus can exhibit improved sound absorption capabilities even in mid and low frequency bands from 200 Hz to 2000 Hz by a principle of micro resonance
Implementation Method 2
Sound absorption capabilities of the non-woven fabrics are attributed to a porous sound absorption principle formed by micro fibers constituting the non-woven fabrics
Implementation Method 3
forming convex-concave patterns having protrusions and depressions on one surface of the porous substrate through thermal transfer
Data Source
AI summary
Disclosed are a sound absorbing sheet having a micro resonant structure and capable of improving sound absorption performance up to the low frequency band by means of the micro resonance principle, a method for manufacturing same, and a sound absorption type soundproof panel using same. The sound absorbing sheet according to the present invention has multiple uneven patterns configured to have convex parts and concave parts on one surface of a porous base material, and the area ratio of the concave part determined by the following formula 1 is 40 to 99%. The area corresponding to the concave part has a lower air permeability than the area corresponding to the convex part.Area ratio of concave portion=[area portion of concave portion]/[area portion of porous base material]. [Formula 1]