Porous Composite Tooling Assembly for Acoustic Attenuation
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Solution Overview
Problem
Conventional acoustically treated composite structures for sound attenuation are expensive and time-intensive to produce, with processes like abrasive perforation and mechanical drilling being costly and fiber-damaging, and plastic pin mats being non-reusable.
Innovation Solution
A tooling assembly and method for manufacturing porous composite structures using a first and second tooling member with perforations, where fluid is flowed through the layup to displace resin matrix and form tortuous paths, reducing material costs and production time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional abrasive perforation or mechanical drilling is used to create perforations in composite structures, then perforations can be formed, but the process is time-intensive, has high material costs, and damages fibers reducing facesheet strength
Solution Approach 1:
The patent replaces mechanical drilling or abrasive perforation systems with a fluid injection system. Fluid is injected through a tooling member into the green composite layup, using fluid pressure to create perforations and tortuous paths without mechanical contact. This substitution eliminates drill bit replacements, reduces cycle time, and prevents fiber cutting that diminishes facesheet strength.
Solution Approach 2:
The patent uses hydraulic or pneumatic fluid injection through a tooling member to create perforations and tortuous paths in the composite layup. The fluid moves through the green composite material, displacing resin matrix and forming the desired porous structure without mechanical drilling, thereby reducing cycle time and material costs while maintaining structural integrity.
2Ease of manufacture
If plastic pin mats are used to create perforations, then perforations can be formed, but the mats are non-reusable and require contouring and trimming for one-time usage
Solution Approach 1:
The patent employs reusable tooling members with defined perforation patterns that can be recovered and reused for multiple production cycles. Unlike single-use plastic pin mats that require discarding after one use, the tooling members are durable fixtures that can be cleaned and reused, significantly reducing material waste and production costs for creating perforations in composite structures.
3Strength
If conventional bonding processes are used to bond facesheets to honeycomb cores, then bonding can be achieved, but multiple cure cycles are required increasing production time
Solution Approach 1:
The patent merges the perforation creation process with the bonding and curing process. By injecting fluid through the tooling member during the layup assembly stage, the perforations and tortuous paths are formed simultaneously with the bonding process, eliminating the need for separate cure cycles and reducing overall production time while maintaining bond strength.
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 method enables efficient and cost-effective production of porous composite structures with tortuous paths that effectively attenuate sound, comparable to traditional drilled facesheets bonded to a septumized honeycomb core, without the drawbacks of conventional methods.
Implementation Method 1
establishing a flow of fluid through the plurality of first perforations, through the layup, and through the plurality of second perforations
Implementation Method 2
flow of fluid through the layup to displace resin matrix and form tortuous paths
Implementation Method 3
Acoustically treated composite structures reduce sound by scattering or absorbing sound energy
Implementation Method 4
the cavities in the core act as Helmholtz resonators and attenuate the sound of the associated airflow
Data Source
AI summary
A tooling assembly for manufacturing a porous composite structure. The tooling assembly includes a first tooling member and a second tooling member. The first tooling member includes a first body that defines a first internal volume and a first inlet. The first inlet is fluidly coupled with the first internal volume. The first tooling member also includes a first tooling surface that defines a plurality of first perforations that are fluidly coupled with the first internal volume. The second tooling member includes a second body that defines a second internal volume and a second inlet. The second inlet is fluidly coupled with the second internal volume. The second tooling member also includes a second tooling surface that defines a plurality of second perforations that are fluidly coupled with the second internal volume.