Flexible Composite Drive Shaft with Spiral Elements

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Solution Overview

Problem

The high cost and labor-intensive nature of metallic flexible diaphragm couplers used in drive shafts for rotary wing aircraft, which are expensive to fabricate and require strict quality standards, necessitates a more cost-effective and efficient solution for bending and axial flexibility.

Innovation Solution

A composite drive shaft with a web-based body featuring bi-directional spiral composite elements embedded within composite layup end sections, formed from uni-directional fiber-reinforced polymer-matrix composite structures, providing enhanced bending stiffness and flexibility through a spiral net design with periodic joints and reinforcing pads, fabricated using automated or manual methods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If metallic flexible diaphragm couplers are used to provide bending and axial flexibility, then the drive shaft can accommodate geometrical imperfections and mutual movements, but the fabrication cost and labor intensity increase significantly

Engineering Contradiction:

Improvebending and axial flexibilityVSAvoidfabrication cost and labor intensity

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent applies composite materials by constructing the drive shaft from multiple composite plies with different fiber orientations (0°, ±45°, 90°) arranged in a laminated structure. This composite construction provides the necessary flexibility and adaptability while being more cost-effective and easier to manufacture than traditional metallic couplers, as the composite layers can be laid up and cured in situ to achieve the desired mechanical properties without complex welding or assembly operations

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent segments the drive shaft structure into distinct functional zones: composite layup end sections at each end and a spiral wire rope net structure in the intermediate portion. This segmentation allows each section to be optimized independently - the end sections provide rigid connection interfaces while the spiral net provides flexibility, eliminating the need for separate metallic flexible coupler components

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

Engineering Contradiction:

Improvebending and axial flexibilityVSAvoidfabrication time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent employs preliminary action by pre-configuring the composite plies with specific fiber orientations and angles before final curing. The spiral wire rope net is also pre-formed with the appropriate geometry and tension characteristics. These preliminary preparations allow for quality control to be exercised during manufacturing rather than during final assembly, reducing fabrication time while maintaining the necessary flexibility characteristics

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The composite material system allows for integrated fabrication where multiple functional requirements (structural integrity, flexibility, vibration damping) are achieved through a single laminated structure rather than assembling multiple metallic components. This reduces both fabrication time and complexity by eliminating welding, machining, and precise alignment operations required for metallic couplers

Inventive Principle:

Principle #40Composite materials

3Strength

If bi-directional spiral composite elements are embedded in composite layup end sections, then structural efficiency is enhanced while maintaining flexibility, but the manufacturing process complexity increases

Engineering Contradiction:

Improvestructural efficiencyVSAvoidmanufacturing process complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent applies local quality by embedding the bi-directional spiral composite elements specifically within the composite layup end sections where high structural efficiency is needed, while the intermediate portion uses a spiral wire rope net structure. This localized approach optimizes strength where required without unnecessarily complicating the entire manufacturing process, as different sections can be fabricated using techniques best suited to their functional requirements

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20240110592A1Flexible composite drive shaft

Publication Date: 2024.04.04 GOODRICH CORP

AI summary

A composite drive shaft includes a web-based body defining a longitudinal axis. The web-based body has a first composite layup end section, a second composite layup end section that is opposite to the first composite layup end section, a first spiral composite element extending between the first composite end section and the second composite layup end section, and a second spiral composite element 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.