Curved Shaft Coupling Pocket Structure for Durable Blade Attachment
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Solution Overview
Problem
Existing methods for attaching curved structures, such as wind turbine blades, to central shafts often result in reduced durability due to mismatched thicknesses and perpendicular forces, leading to structural weaknesses and aerodynamic inefficiencies.
Innovation Solution
A coupling system with coupling members and fastening members that maintain consistent thickness and provide perpendicular attachment surfaces, using pockets and flange portions on both inner and outer surfaces of the curved object, ensuring smooth curvature transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If existing methods are used to attach curved structures to central shafts, then assembly is simplified, but structural strength and durability are reduced due to mismatched thicknesses and perpendicular forces
Solution Approach 1:
The attachment structure is divided into multiple components: a coupling member with a first end for the shaft and a second end for the curved structure, a pocket structure with flat and flange portions, and fastening members. This segmentation allows each component to be optimized for its specific function while distributing structural stresses across multiple elements rather than concentrating them in a single attachment point.
Solution Approach 2:
The coupling member acts as an intermediary element between the central shaft and the curved structure. It transfers loads and forces between these two components while the pocket structure with its flange portion provides an intermediate attachment surface that accommodates the coupling member, thereby mediating the connection and reducing direct stress concentrations.
2Ease of manufacture
If conventional attachment methods are used, then manufacturing is simpler, but aerodynamic efficiency is reduced due to interference from attachment structures
Solution Approach 1:
The pocket structure is designed with different local geometries optimized for specific functions: the flat portion provides a perpendicular mounting surface for the coupling member, the flange portion integrates smoothly with the curved surface to maintain aerodynamic flow, and the overall pocket geometry is shaped to minimize aerodynamic interference while accommodating the attachment hardware.
Solution Approach 2:
The flange portion is designed with a curved geometry that merges continuously with the curved surface of the curved structure. This curvature allows the attachment structure to follow the aerodynamic contours of the main body, reducing flow separation and turbulence that would occur with sharp edges or flat surfaces perpendicular to the flow.
3Reliability
If thin attachment surfaces are used, then material usage is reduced, but stress concentrations increase leading to reduced durability
Solution Approach 1:
The attachment structure utilizes three-dimensional geometry to distribute stresses effectively. The flange portion extends in multiple directions from the flat portion, creating a distributed attachment system rather than a single thin surface. This multi-dimensional configuration allows loads to be spread across a larger volume of material, reducing stress concentrations while maintaining reasonable material usage.
Solution Approach 2:
The invention accommodates both metal components (coupling member, fastening members) and composite or plastic curved structures. The design allows for different material properties to be combined, where the metal coupling member provides high strength and stiffness, while the curved structure can be made from lighter composite materials, optimizing the overall strength-to-weight ratio and durability.
Data Source
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AI summary
A coupling system for coupling a curved object to a central shaft, the curved object includes an inner surface facing the central shaft and an outer surface. The system includes a coupling member for coupling the curved object to the central shaft; at least one pocket integrally formed on a curved surface of the curved object and defined as a depression with respect to at least one of the inner and outer surfaces. The pocket includes: a flat portion having an aperture for holding the coupling member; and a flange portion which merges continuously from the flat portion to the curved object and is shaped such that the flat portion is disposed perpendicularly to the coupling member; a fastening member for fastening the coupling member to the flat portion. The thickness of the flat portion and flange portion is the thickness of the curved object.