Composite Drive Shaft With Spiral Layup for Flexible Coupling
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Solution Overview
Problem
The existing metallic flexible diaphragm couplers used in drive shafts for rotary wing aircraft are expensive, labor-intensive, and require strict quality standards, limiting the integration of bending and axial flexibility, which increases costs and reduces structural efficiency.
Innovation Solution
A composite drive shaft with a web-based body featuring bi-directional spiral composite elements embedded in uni-directional fiber-reinforced polymer-matrix composite structures, arranged at predetermined angles, and connected through periodic joints with reinforcing pads, formed using automated fiber placement or manual layup methods, to enhance flexibility and stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If metallic flexible diaphragm couplers are used in drive shafts, then bending and axial flexibility is provided, but fabrication cost and labor intensity increase significantly
Solution Approach 1:
The patent applies composite materials by constructing the drive shaft from multiple composite layers including spiral wound composite layers and circumferential composite layers. These composite structures provide the necessary flexibility while being more cost-effective and less labor-intensive to fabricate than traditional metallic couplers. The composite construction allows for integrated bending and axial flexibility without requiring separate metallic diaphragm couplings.
2Adaptability or versatility
If metallic flexible diaphragm couplers are used in drive shafts, then flexibility is achieved, but structural efficiency is reduced
Solution Approach 1:
The patent applies segmentation by dividing the drive shaft into distinct functional layers: spiral wound composite layers that provide torsional flexibility, circumferential composite layers that provide structural strength, and end cap assemblies. This segmentation allows each layer to be optimized for its specific function, with the spiral layers providing flexibility and the circumferential layers maintaining structural efficiency, avoiding the compromise inherent in monolithic metallic designs.
Solution Approach 2:
The patent applies local quality by varying the material properties and structural characteristics at different locations and layers of the drive shaft. The spiral wound composite layers have different properties than the circumferential composite layers, with each layer tailored to provide specific local functions. This allows the shaft to have high flexibility where needed while maintaining overall structural efficiency.
3Adaptability or versatility
If metallic flexible diaphragm couplers are used, then coupling flexibility is provided, but quality standards and approval processes become more stringent
Solution Approach 1:
The patent applies merging by integrating the flexible coupling function directly into the drive shaft structure itself through composite construction, rather than using separate metallic diaphragm coupler components. This integration simplifies the overall system, reduces the number of parts requiring quality certification, and eliminates the need for complex approval processes associated with metallic couplers while maintaining the necessary coupling flexibility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composite drive shaft design reduces costs, simplifies fabrication, and enhances structural efficiency by providing flexibility under torsion, axial tension, and compression without the need for high-performance precision welds, while maintaining mechanical integrity.
Implementation Method 1
The first spiral composite element and the second spiral composite element are arranged in a bi-directional orientation relative to the longitudinal axis and possess a uni-directional fiber-reinforced polymer-matrix composite structure
Implementation Method 2
the first composite layup end and the second composite layup have a bending stiffness along the longitudinal axis that is greater than the bending stiffness along the longitudinal axis of remaining portions of the web-based body
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 2A~2B
AI summary
A composite drive shaft includes a web-based body (11) defining a longitudinal axis. The web-based body has a first composite layup end section (50), a second composite layup end section (52) that is opposite to the first composite layup end section, a first spiral composite element (28) extending between the first composite end section and the second composite layup end section, and a second spiral composite element (32) extending between the first composite end section and the second composite layup end section. The first spiral composite element and the second composite spiral element are embedded into the first composite layup end section, and the second composite layup end section. The first composite spiral element and the second composite spiral element are arranged in a bi-directional orientation relative to the longitudinal axis. The first spiral composite element and the second spiral composite element are arranged at pre-determined angles and possess a uni-directional fiber-reinforced polymer-matrix composite structure.