Acoustic Composite for Lightweight Sound Absorption
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Solution Overview
Problem
Existing sound absorbers fail to effectively manage both acoustic absorption and transmission loss, particularly at lower frequencies, and are often heavy due to the need for increased mass.
Innovation Solution
Development of an acoustic composite comprising a flow resistive substrate with a solid acoustic barrier material bonded to its surface, featuring a density greater than 1 g/cm3 and porosity between 0.002% and 50%, which includes microperforated films and structured films with tubular projections, providing both acoustic absorption and transmission loss while maintaining a lightweight structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mass is increased to control low frequency transmission loss, then transmission loss is improved, but weight increases
Solution Approach 1:
The invention uses a composite structure combining a flow resistive substrate (providing acoustic absorption) with a solid acoustic barrier material (providing transmission loss). This composite approach allows the system to achieve both acoustic absorption and transmission loss functions simultaneously, eliminating the need for excessive mass while maintaining effective low frequency transmission loss control.
Solution Approach 2:
The flow resistive substrate is designed with controlled porosity (between 0.002% and 50%) to optimize acoustic flow resistance. This porous structure enables effective acoustic absorption without requiring dense, heavy materials, thereby reducing overall weight while maintaining transmission loss performance.
2Reliability
If mass is increased to control low frequency transmission loss, then transmission loss is improved, but device complexity increases
Solution Approach 1:
The invention merges two functional components into a single integrated acoustic composite: the flow resistive substrate that provides acoustic absorption and the solid acoustic barrier material that provides transmission loss. This combination achieves both functions simultaneously in one component, reducing system complexity compared to using separate heavy mass layers and absorption materials.
3Weight of moving object
If porosity is increased to reduce weight, then weight is reduced, but transmission loss deteriorates
Solution Approach 1:
The acoustic composite combines a flow resistive substrate with controlled porosity (0.002%-50%) with a solid acoustic barrier material. This composite structure allows the system to achieve both acoustic absorption (from the porous substrate) and transmission loss (from the solid barrier) without requiring excessive density, thereby reducing weight while maintaining transmission loss 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 acoustic composite effectively absorbs sound and reduces transmission loss across a wide frequency range, including lower frequencies, while maintaining a lightweight and cost-effective design, suitable for various applications including automotive and industrial use.
Implementation Method 1
the acoustic composite effectively absorbs sound
Implementation Method 2
solid acoustic barrier material bonded to at least a portion of a major surface of the flow resistive substrate
Data Source
AI summary
An acoustic composite comprises a flow resistive substrate having a solid acoustic barrier material bonded to at least a portion of a major surface of the flow resistive substrate; wherein the acoustic barrier material has a density greater than about 1 g/cm3 and the acoustic composite has a porosity between about 0.002% and about 50%.