Composite Angle Bracket with Curved Profiles for Folding Stress
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Solution Overview
Problem
Composite material angle irons used in aeronautics lack sufficient resistance to folding and unfolding stresses and longitudinal rigidity, as the resin matrix fails under tensile and compressive forces, while the reinforcing fibers are not adequately stressed, leading to suboptimal performance compared to traditional metal angle irons.
Innovation Solution
The angle iron features a unique geometry with curved concave or convex profiles along the longitudinal direction, separated coupling zones, and radial holes for fastening, ensuring that the reinforcing fibers bear the primary load, minimizing stress on the resin matrix, and providing increased resistance and rigidity through a specific molding process using carbon fibers and epoxy resin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If composite material angle irons are made using conventional molding techniques, then weight is reduced, but resistance to folding and unfolding stresses is insufficient due to resin matrix failure
Solution Approach 1:
The patent applies curvature by molding the composite material angle iron with domed parts (convex regions) along its length. These curved sections create structural reinforcement that distributes folding and unfolding stresses across the fiber-reinforced composite, preventing resin matrix failure while maintaining weight advantages. The curvature transforms stress concentration points into distributed stress zones.
Solution Approach 2:
The patent utilizes fiber-reinforced composite materials with specific fiber orientations aligned to resist folding and unfolding forces. The composite structure combines lightweight properties with enhanced strength through strategic fiber placement in the domed parts, allowing the angle iron to achieve both weight reduction and improved resistance to bending stresses.
2Strength
If L-shaped fittings are used to join parts, then resistance to folding stress is improved, but longitudinal rigidity is insufficient due to lack of connection between fittings
Solution Approach 1:
The patent merges multiple L-shaped fitting functions into a single continuous composite angle iron structure. The domed parts create integrated reinforcement zones that provide both folding resistance and longitudinal continuity, eliminating the need for separate connected fittings and ensuring rigid load transfer along the entire length of the angle iron.
Solution Approach 2:
The domed parts with radial holes create curved reinforcement zones that simultaneously resist folding stresses and provide longitudinal structural continuity. The curvature distributes loads along the length of the angle iron, ensuring both bending resistance and longitudinal rigidity without requiring additional connection elements.
3Ease of operation
If holes are made in flat surfaces for fastening, then ease of assembly is improved, but stress concentration occurs in the resin matrix
Solution Approach 1:
The patent places fastening holes in radially oriented positions on the domed parts rather than on flat surfaces. This curved geometry distributes fastening loads radially across the fiber-reinforced structure, preventing stress concentration in the resin matrix while maintaining ease of assembly through standardized hole placements.
Solution Approach 2:
The patent creates localized domed parts with specific geometric properties optimized for fastening. These regions have enhanced local strength and controlled stress distribution characteristics, allowing reliable assembly while protecting the resin matrix from excessive stresses at hole locations.
Data Source
AI summary
The invention relates to an angle bracket (2) consisting of a composite material for connecting parts, said angle bracket comprising two wings (3, 4) forming an angle along a longitudinal folding axis (20) and having coupling regions (34, 44) on the outside of the fold, for attaching the parts to be connected, associated with securing means. At least in the longitudinal direction, said angle bracket has at least one succession of domed sections (21, 31, 41) with a concave or convex profile on the inside and/or outside of said fold, providing it with a corrugated form in the longitudinal direction.