Carbon Acoustic Matching Layer for Impedance Gradient
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing acoustic matching layers face challenges in achieving adequate mechanical strength, minimizing sound wave loss at boundary surfaces, and effectively varying acoustic impedance in the thickness direction, while also preventing delamination and bending during carbonization.
Innovation Solution
A carbon-based acoustic matching layer is developed with amorphous carbon as the matrix, where filler particles are uniformly dispersed to adjust acoustic impedance within a specific range, and the layers are integrated by simultaneous carbonization in a laminated state, reducing the coefficient of linear contraction difference between layers to prevent cracking and bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive is used for laminating materials having different acoustic impedance, then the layers can be joined together, but delamination and acoustic impedance mismatch problems occur
Solution Approach 1:
The patent merges the bonding function and acoustic matching function into a single integrated structure. The porous body structure allows acoustic waves to pass through while the interpenetration of materials creates mechanical bonding, eliminating the need for separate adhesive layers that cause delamination issues.
Solution Approach 2:
The patent employs a porous body as the core structure for acoustic matching layers. The porous structure provides both acoustic impedance matching capabilities and mechanical interlocking with adjacent layers, preventing delamination while maintaining acoustic performance.
2Strength
If multiple layers with different acoustic impedance are laminated without adhesive, then delamination is prevented and mechanical strength is enhanced, but sound wave reflection loss at boundary surfaces increases
Solution Approach 1:
The porous body structure creates gradual acoustic impedance transitions at layer boundaries. The porous structure allows acoustic waves to penetrate through boundary surfaces more effectively, reducing reflection loss while maintaining the mechanical strength benefits of adhesive-free lamination.
Solution Approach 2:
The patent implements a nested structure where the porous body of one layer interpenetrates with the porous body of adjacent layers. This interpenetration creates a continuous acoustic pathway while maintaining mechanical bonding, reducing boundary reflections without requiring adhesives.
3Quantity of substance
If graphite particles are mixed into furan resin to create carbon-based porous body, then acoustic impedance changes in thickness direction are achieved, but the amount of change is limited and boundaries between layers remain
Solution Approach 1:
The patent merges adjacent porous layers through interpenetration and simultaneous carbonization. This process eliminates well-defined boundaries between layers while maintaining acoustic impedance gradients, achieving both compositional stability and adequate acoustic impedance variation.
Solution Approach 2:
The patent utilizes parameter changes during carbonization to merge layers. By controlling the carbonization process, the porous structures of adjacent layers integrate, eliminating boundaries while preserving the acoustic impedance gradient needed for matching.
4Ease of manufacture
If filler particles are incorporated into all layers at the same ratio, then manufacturing is simplified, but the amount of change in acoustic impedance in the direction of thickness is limited
Solution Approach 1:
The patent applies local quality by varying filler particle ratios in different layers. Each layer has optimized filler content specific to its acoustic impedance requirements, enabling greater overall acoustic impedance variation while maintaining manufacturing feasibility through a systematic approach.
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 carbon-based acoustic matching layer achieves enhanced mechanical strength, reduced sound wave loss, increased acoustic impedance variation in thickness, and improved processability, with superior chemical and heat resistance, and constant electrical conductivity.
Implementation Method 1
heating the laminate in a non-oxidizing atmosphere to amorphously carbonize the carbon-containing resin of the filler-containing resin composition
Implementation Method 2
the amorphous carbon of two adjacent layers is integrated, and two adjacent layers contain filler particles of mutually different types and/or content ratios
Implementation Method 3
each of the plurality of layers contains amorphous carbon and filler particles dispersed in the amorphous carbon
Data Source
Figure 1
AI summary
Provided are: a carbonaceous acoustic matching layer which exhibits satisfactory mechanical strength, in which losses at a layer interface are suppressed as far as possible and in which the degree of variation in acoustic impedance in the thickness direction can be increased; and a method for producing same. The carbonaceous acoustic matching layer is obtained by dispersing filler particles, which are selected on the basis of the desired acoustic impedance of each layer, in a resin such as a furan resin, a phenol resin or a vinyl chloride resin, curing, laminating, and then carbonizing the resin by heating in a non-oxidizing atmosphere, amorphous carbon, which is obtained by the resin carbonization, is integrated across all the layers. The blending proportion of the filler particles is decided so that the difference in coefficient of linear contraction caused by the carbonization is at a minimum between adjacent layers.