Composite Panel Stiffener Mesh for Torsional Rigidity
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Solution Overview
Problem
Existing self-stiffened monolithic composite panels used in aircraft parts, such as hatch doors and landing gear, face challenges with high mass and production cost due to the need for thick components to achieve sufficient torsional rigidity, and they often lack adequate torsional stiffness.
Innovation Solution
A self-stiffened monolithic composite panel design featuring a lattice of stiffeners oriented in directions neither parallel nor perpendicular to the axis of rotation, with a main structural reinforcement comprising a mesh of stiffeners in a cross configuration, and additional peripheral and transverse stiffeners, which reduces the need for closed-section stiffeners and allows for open-section designs, thereby minimizing mass and cost while enhancing torsional rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thick components and closed-section stiffeners are used to achieve sufficient torsional rigidity, then the panel maintains structural integrity, but the mass and production cost increase significantly
Solution Approach 1:
The panel structure is segmented into discrete stiffeners arranged in a specific pattern rather than using solid thick sections. The stiffeners are positioned at strategic locations (peripheral, transverse, and cross configurations) to provide torsional rigidity through distributed reinforcement rather than concentrated mass.
Solution Approach 2:
The patent employs composite materials with fiber orientations optimized for torsional loading. The stiffeners and skin are constructed using composite laminates with specific ply arrangements that provide high torsional stiffness-to-weight ratio, eliminating the need for thick solid sections.
2Strength
If parallel stiffeners oriented perpendicular to the axis of rotation are used, then torsional rigidity is improved, but the number of stiffeners and overall mass increase
Solution Approach 1:
Instead of using numerous parallel stiffeners, the structure is segmented into a fewer number of strategically positioned stiffeners including peripheral stiffeners along the edges, transverse stiffeners across the panel, and cross stiffeners forming orthogonal patterns. This segmentation provides equivalent or superior torsional rigidity with reduced component count.
Solution Approach 2:
The stiffener arrangement transitions from a single-dimensional parallel pattern to a two-dimensional network comprising peripheral, transverse, and cross stiffeners. This multi-directional configuration creates a more efficient torsional resistance system that requires fewer individual stiffeners while maintaining structural performance.
3Strength
If closed-section omega stiffeners are used to ensure sufficient torsional stiffness, then structural integrity is maintained, but manufacturing complexity and cost increase
Solution Approach 1:
The stiffeners are constructed using composite materials with optimized fiber layouts that provide high torsional stiffness. The composite construction allows for open-section profiles with strategically placed fibers that achieve the same structural performance as closed-section metal stiffeners but with lower manufacturing complexity and cost.
Solution Approach 2:
The stiffener cross-sectional geometry is changed from closed-section omega profiles to open-section configurations. This parameter change, combined with optimized composite material placement, maintains the necessary torsional stiffness while significantly simplifying the manufacturing process and reducing production costs.
Data Source
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AI summary
The invention relates to a panel pivoting about an axis parallel to a side of the panel, which comprises a first continuous coating (1), a main structural frame of a composite stiffener (2, 3, 4, 5, 6) connected to the coating (1) and including a stiffening mesh (2, 3) with at least one pair of cross-shaped stiffeners each oriented in one of two directions, respectively, not parallel or perpendicular to the rotation axis. The two parts (3a, 3b) of each stiffener (3, 2) extending on either side of the centre of the cross are in structural continuity, and the two stiffeners (2, 3) each have an end located at one point (A, B, C) on the side of the panel parallel to the rotation axis, wherein the end is connected to a rigid member for connection to the rotation axis, the opposite end of at least one stiffener being blocked in rotation on a bearing point on the opposite side of the panel.