Composite Drive Shaft Filler Edge Geometry
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Solution Overview
Problem
Composite structures, such as drive shafts, face damage initiation risks due to gaps formed at non-uniform thickness areas, particularly at the ends of plies, where conventional designs with straight edges lead to stress concentrations and reduced damage tolerance.
Innovation Solution
The use of composite strips with filler edges having non-straight geometries, such as chamfers or double bevels, to prevent or reduce gaps between adjacent strips, thereby enhancing damage tolerance by distributing stress more evenly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If straight edges are used at the ends of plies, then manufacturing is simpler, but gaps form between adjacent strips causing stress concentrations and reduced damage tolerance
Solution Approach 1:
The patent applies curvature by replacing straight edges with curved filler edges at the ends of plies. The curved geometry allows adjacent composite strips to blend smoothly without gaps, eliminating stress concentrations while maintaining manufacturing feasibility through standard cutting and fitting operations.
Solution Approach 2:
The invention applies local quality by introducing filler edges only at specific locations where gaps occur (at the ends of plies in non-uniform thickness areas), rather than modifying the entire structure. This localized approach addresses the specific problem areas while leaving the rest of the composite structure unchanged.
2Strength
If tapered shapes are designed in zones of joints or rub-rings to add extra thickness, then local stress concentrations are compensated, but gaps still form at the ends of plies reducing damage tolerance
Solution Approach 1:
The curved filler edges complement the tapered shapes by providing smooth transitions at the ends of plies. This combination of tapered geometry in joint zones and curved filler edges at ply ends creates a cohesive structure that eliminates gaps and stress concentrations throughout the entire composite structure.
Solution Approach 2:
The invention maintains the localized approach by applying filler edges only where gaps occur at the ends of plies, while preserving the tapered shape design in joint and rub-ring zones. Each local area is optimized for its specific function without compromising the overall structural integrity.
Data Source
AI summary
In accordance with at least one aspect of this disclosure, a composite structure can be formed of or including a plurality of composite strips. The plurality of composite strips include one or more filler strips which can have at least one filler edge having a filler edge geometry between a first surface and second surface, the second surface being opposite the first surface. The filler edge geometry can be configured to prevent formation of one or more gaps between one or more adjacent composite strips.