Sewn Composite Belly Fairing Panels to Prevent Fire Delamination
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Solution Overview
Problem
Large composite panels for aircraft, such as belly fairings, face issues with fire resistance due to resin fluidity causing delamination, which is currently addressed by riveted T profiles but lacks comprehensive fire protection.
Innovation Solution
A method involving sewing overlapping layers of fabric or textile mats with high fire-resistant thread, forming seams perpendicular to the layer surfaces, and using materials like carbon and glass fibers to enhance fire resistance and prevent delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If resin is used to bond fabric layers, then the composite panel achieves structural integrity, but under fire conditions the resin becomes fluid and layers delaminate
Solution Approach 1:
The bonding function is segmented between the sewing thread (providing mechanical anchoring) and the resin (providing matrix consolidation). The sewing creates discrete bonding points through layers that remain effective even when resin fails under fire conditions.
Solution Approach 2:
The sewing thread acts as an intermediary mechanical anchor between fabric layers, providing a fire-resistant bonding mechanism that operates independently of the resin matrix. This intermediary connection prevents delamination when the resin becomes fluid under fire.
2Reliability
If T profiles with rivets are used to hold fabric tapes, then fire resistance is improved, but device complexity and manufacturing complexity increase
Solution Approach 1:
The extruded T profiles are completely removed from the structure. Instead, sewing threads directly anchor the fabric layers to each other, eliminating the need for separate mechanical retention profiles while maintaining fire resistance.
Solution Approach 2:
The bonding function previously separated into T profiles and resin is merged into a single integrated sewing process. The sewing thread combines mechanical anchoring and layer integration functions that were previously distributed across multiple components.
3Reliability
If sewing is performed across all layers, then delamination is prevented under fire conditions, but manufacturing complexity increases
Solution Approach 1:
The complex mechanical riveting system with T profiles is replaced by a simpler sewing mechanism. The sewing process uses a single continuous or interrupted thread to anchor layers, reducing the number of components and assembly steps while achieving the same fire-resistant bonding effect.
Data Source
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AI summary
In a method of making a composite panel (14) for an aircraft, in particular formed as a belly fairing, a plurality of layers (16, 17, 18) are arranged on top of each other to form a layer arrangement (20), wherein each layer (16, 17, 18) is formed by a number of mats (22, 23) made of a textile, which are laterally adjacent to each other and overlap each other to form one or more overlapping areas (26) in each layer (16, 17, 18) of the layer arrangement (20). The mats (22, 23) are impregnated with a matrix material. Sewing is performed across all layers (16, 17, 18) of the layer arrangement (20) at least at an edge (28) thereof, and/or in the overlapping areas (26) of at least one of the outer layers (16, 18) of the layer arrangement (20). One or more seams (32) are created. The matrix material is consolidated after sewing the layer arrangement (20).