Multilayer Automotive Sound Absorption Material Without Aperture Fouling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing sound-absorbing materials for vehicles, such as those using frequency selection plates with apertures, face issues with dirt accumulation and unstable sound absorption performance, and fail to effectively reduce weight while maintaining desired sound absorption.
Innovation Solution
A multilayer sound-absorbing material with a core layer of tubular cells and airflow-blocking resin film layers, where the Young's modulus and surface density of the resin film layers are optimized to achieve stable sound absorption across the frequency band of 500 Hz to 8000 Hz, eliminating the need for apertures and ensuring high rigidity with reduced weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frequency selection plates with apertures are used for sound absorption, then sound damping effect is achieved through air friction, but dirt accumulates in the apertures causing unstable sound absorption performance
Solution Approach 1:
The invention removes the aperture structure from the sound absorption material. Instead of using frequency selection plates with holes that trap dirt, the patent employs a closed-cell foam core layer combined with airflow-blocking resin film layers that achieve sound absorption through a different mechanism (acoustic resonance and friction within closed cells), completely eliminating the dirt accumulation problem while maintaining reliable performance
Solution Approach 2:
The invention uses closed-cell foam as the core material, which provides sound absorption through its cellular structure. The closed cells create acoustic resistance and friction for sound waves without requiring open apertures, thus achieving effective sound damping while preventing dirt ingress that would occur with open-hole structures
2Strength
If thermoplastic resin components are heated and press-molded to form uneven-shaped components, then structural integrity and shape control are achieved, but weight reduction is limited
Solution Approach 1:
The invention creates a composite structure by adhering airflow-blocking resin film layers to both surfaces of the closed-cell foam core layer. This composite design combines the structural integrity of thermoplastic resin with the sound absorption properties of the foam and resin film, achieving both mechanical strength and acoustic performance while reducing overall weight compared to solid thermoplastic components
Solution Approach 2:
The airflow-blocking resin film layers serve as thin film structures that provide structural reinforcement and sound absorption functionality. These films are lighter than solid thermoplastic components while maintaining the necessary structural integrity when combined with the foam core, enabling weight reduction without sacrificing strength
3Adaptability or versatility
If aperture structures are used for frequency selection, then specific frequency transmission or blocking is achieved, but the desired sound absorption performance cannot be stably obtained due to dirt accumulation
Solution Approach 1:
The invention changes the fundamental parameter of the sound absorption mechanism from aperture-based frequency filtering to closed-cell resonance absorption. By using closed-cell foam with specific cell structures and combining it with resin film layers, the material achieves frequency-dependent sound absorption without requiring open apertures, thereby maintaining stable performance across different frequencies without dirt accumulation interference
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 material achieves desired sound absorption performance with peaks in the 500 Hz to 8000 Hz frequency band, providing improved noise reduction in vehicles while maintaining structural integrity and preventing dirt accumulation.
Implementation Method 1
the interior and exterior components of vehicles are required to have a function of absorbing noise in these frequency bands
Implementation Method 2
a sound damping effect is expected due to the friction of air passing through the aperture of the frequency selection plate
Implementation Method 3
a first airflow-blocking resin film layer adhered to one surface of the core layer
Data Source
AI summary
There is provided a sound-absorbing material for a vehicle, capable of stably yielding desired sound absorption performance while reducing weight of the sound-absorbing material for a vehicle. The sound-absorbing material for a vehicle of the present invention has a multilayer structure, including: a core layer in which tubular cells are arranged in a plurality of rows; and an airflow-blocking resin film layer adhered to one surface of the core layer. The relationship between the Young's modulus E (MPa) of the airflow-blocking resin film layer 40 and the surface density M (g/m2) of the layer structure on the first airflow-blocking resin film layer 40 side with respect to the core layer 10 is 0.5<E/M<21.