Acoustic Panel with Granular Thermofusible Layer
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Solution Overview
Problem
Existing acoustic protection panels for motor vehicles face challenges in maintaining effective acoustic insulation and absorption properties while minimizing thickness and avoiding over-compression, which reduces porosity and increases air resistance.
Innovation Solution
Incorporating a porous granular layer based on crushed thermofusible material with a Young's modulus greater than 1 MPa between the porous sound-absorbing layer and the thermoplastic sealing film, allowing for a stiffening function and weight distribution without significant thickness increase, and using a thermoplastic sealing film and elastically compressible spring layer to form a 'mass/spring' system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the porous layer is over-compressed to minimize thickness, then the thickness is reduced, but the porosity decreases and air resistance increases drastically, harming acoustic absorption properties
Solution Approach 1:
The patent uses a composite structure combining a porous sound-absorbing layer with a granular thermofusible material layer. The granular layer has high density and forms an impermeable barrier that provides acoustic insulation without compressing the porous layer, thus maintaining its porosity and absorption properties while achieving thickness reduction through the lightweight granular material.
Solution Approach 2:
The patent employs a porous sound-absorbing layer with controlled porosity (30-70%) that is not over-compressed. This porous structure maintains low air resistance and good acoustic absorption properties by preserving its void space, while the thickness constraint is addressed by the accompanying granular layer that provides insulation without requiring compression of the porous material.
2Length of stationary object
If the film has a very low surface mass, then the panel thickness can be minimized, but the acoustic insulation performance cannot be optimized
Solution Approach 1:
The patent creates a composite mass system using a thin film (low surface mass) combined with a granular thermofusible material layer (high surface mass). The granular material, being dense and granular, can be applied in a thin layer yet provides significant mass for acoustic insulation. The combination achieves both thin overall thickness and sufficient acoustic insulation performance.
Solution Approach 2:
The patent changes the density parameter of the material layer by using granular thermofusible material with high density (1500-2500 kg/m³). This allows achieving the required surface mass for acoustic insulation in a thinner layer compared to less dense materials, thus optimizing both thickness and insulation performance.
3Object-generated harmful factors
If a granular layer based on recycled material is used, then environmental sustainability is improved, but the manufacturing process complexity increases
Solution Approach 1:
The patent uses recycled thermofusible material in granular form as the primary component of the insulating layer. This recovered material, which would otherwise be waste, is processed into granules and applied to the panel. This approach improves environmental sustainability by giving recycled material a new useful application in acoustic insulation.
Solution Approach 2:
The granular thermofusible material layer serves multiple functions simultaneously: it provides acoustic insulation through its mass, acts as a stiffening layer for the porous layer, and can be applied as a thin layer to minimize thickness. This multi-functionality simplifies the overall panel design by eliminating the need for separate layers for each function.
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 configuration preserves and enhances acoustic insulation while maintaining absorption properties, reduces air resistance, and allows for the use of recycled materials, achieving improved acoustic performance without noticeable thickness increase and minimizing fuel consumption.
Implementation Method 1
a porous heat-conformable sound-absorbing layer
Implementation Method 2
the porosity of the porous layer is reduced
Implementation Method 3
acoustic insulation according to a 'mass/spring' principle, the mass being formed by said porous layer associated with said film and the spring by said layer of spring
Implementation Method 4
by the thermofusible nature of the granular layer, by heating said layer during manufacture of the panel, the cohesion between said granular layer and the porous layer and between said granular layer and the film
Implementation Method 5
said porous layer has a Young's modulus in compression greater than 1 MPa, so as to ensure in in addition to a stiffening function
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to an acoustic protection panel (1) for motor vehicles, said panel comprising, arranged successively one on top of the other, a porous layer (2) of heat-conformable acoustic absorption, a thermoplastic sealing film (3) and an elastically compressible spring layer (4), said panel further comprising a porous granular layer (5), based on ground hot-melt material, said granular layer being associated between said porous layer and said film, said porous layer having a Young's modulus in compression greater than 1 MPa, so as to further ensure a stiffening function.