Composite Dome Reinforcement Shell Winding to Reduce Stress Concentration
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Solution Overview
Problem
Existing dome reinforcement shells for pressure vessels in vehicles suffer from stress concentration due to sharp edges and inefficient winding patterns, leading to potential breakage and increased weight, particularly at the dome-shaped ends.
Innovation Solution
The dome reinforcement shell design optimizes the winding pattern by positioning layers with specific start and end angles, eliminating sharp edges and reducing the need for a hoop pattern at the start, thereby minimizing stress concentrations and filament usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a low-angle helical winding pattern is used for the dome reinforcement shell, then the mechanical properties are improved, but the tie-on part becomes complicated to implement requiring a transition from hoop pattern
Solution Approach 1:
The invention extracts and eliminates the unnecessary hoop pattern winding step from the conventional process. By starting directly with the low-angle helical pattern at a specific angle range (5° to 15°) relative to the dome axis, the complex transition sequence is simplified to a single continuous winding operation, reducing procedural complexity while maintaining structural integrity.
Solution Approach 2:
The invention changes the critical parameter of the winding start angle to a specific range (5° to 15°) rather than using the conventional hoop pattern (90°). This parameter optimization allows the filament to achieve both anchorage and mechanical reinforcement in a single continuous pattern, eliminating the need for pattern transitions and simplifying the entire winding operation.
2Ease of manufacture
If a hoop pattern winding is used at the start of the dome reinforcement shell, then the filament can be tied on, but it does not contribute to mechanical properties and increases weight
Solution Approach 1:
The invention extracts and removes the non-contributory hoop pattern layer from the winding sequence. By initiating the low-angle helical pattern directly, the solution eliminates the weight penalty of the hoop layer (typically 5-15% of total filament weight) while the low-angle helical pattern itself provides both anchorage and mechanical reinforcement functions.
Solution Approach 2:
The low-angle helical winding pattern performs multiple functions simultaneously: it provides filament anchorage (traditionally the function of the hoop pattern) and contributes to mechanical reinforcement (the function of the helical pattern). This multi-functionality eliminates the need for separate hoop pattern layers, reducing weight while maintaining ease of manufacture.
3Productivity
If the polar opening of each layer is visible from the outer side, then the winding can be completed, but sharp edges are present causing stress concentration
Solution Approach 1:
The invention changes the winding angle parameter to a low-angle range (5° to 15°) relative to the dome axis. This parameter optimization causes the polar openings of successive layers to overlap and be covered by adjacent filament paths, eliminating visible sharp edges and the associated stress concentration points while maintaining complete winding coverage.
Solution Approach 2:
The invention converts what would normally be a harmful feature (visible polar openings creating sharp edges) into a beneficial outcome by using the low-angle helical pattern. The geometry of this winding pattern causes the filament paths to naturally cover and smooth over the polar openings of underlying layers, transforming potential stress concentration points into smooth, continuous surfaces that enhance structural reliability.
Data Source
Figure 1~2
Figure 3~3d
Figure 4~5
AI summary
This dome reinforcement shell (16; 16') for a pressure vessel consists of a winding of layers of fiber-reinforced composite material tapes, having a dome-shaped portion (22) with a base (24) and a central axis (10), the layers comprising: - at least one proximal layer of fiber-reinforced composite material, the at least one proximal layer having a start angle α1 with respect to the central axis (10) measured at a first end of the proximal layer, with α1 strictly comprised between 0° and 90°, and - at least one distal layer of fiber-reinforced composite material, the at least one distal layer having a start angle α2 with respect to the central axis (10) measured at a first end of the distal layer, with α2 strictly comprised between 0° and α1.