Filament-Wound Composite Shaft With Fibre-Diverted Attachment Holes
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Solution Overview
Problem
Composite shafts formed from Polymer Matrix Composites (PMCs) face challenges in interfacing with other parts due to reduced strength by volume, as standard fixings designed for metal are not suitable, leading to weight and cost increases when metal end fittings are used.
Innovation Solution
A filament wound composite fibre reinforced polymer shaft with helical wound fibres featuring at least one hole perpendicular to the axis, where fibre paths divert around the hole, allowing for reduced metal usage and maintaining structural strength by avoiding fibre cutting, enabling efficient force transmission and weight reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If standard metal fixings are used to interface with the composite shaft, then the connection strength is sufficient, but the weight and cost increase significantly
Solution Approach 1:
The invention merges the shaft body and the attachment feature by integrating a hole directly into the composite shaft structure. The fibres are diverted around the hole during manufacturing, creating a unified structure where the attachment hole is part of the shaft itself, eliminating the need for separate metal end fittings and reducing overall weight.
Solution Approach 2:
The invention uses composite materials (PMCs with helical fibres) to create a shaft that can directly accommodate attachment holes while maintaining strength. The composite structure allows fibres to be diverted around the hole, providing structural integrity without requiring additional metal reinforcement components.
2Shape
If fibres are cut to create a hole in the shaft, then the hole can be formed, but the tensile strength is significantly reduced
Solution Approach 1:
The hole is formed during the preliminary fibre winding process itself, rather than by cutting afterwards. The fibre paths are planned and executed to divert around the hole location during manufacturing, ensuring continuous fibres and maintaining tensile strength while creating the necessary hole shape for attachment.
3Reliability
If metal end fittings are used to connect the shaft, then the connection robustness is ensured, but the cost and weight increase
Solution Approach 1:
The invention extracts and removes the metal end fittings from the design. Instead of using separate metal components for connection, the composite shaft itself is designed with integrated holes that allow direct attachment, eliminating the need for additional metal substances and reducing both weight and cost.
4Adaptability or versatility
If the shaft is designed with holes for attachment, then the connectivity is improved, but the structural strength is compromised
Solution Approach 1:
The fibre winding pattern is locally adapted around the hole area. Fibres are diverted specifically in the regions where holes are located, while maintaining their original helical path in other areas. This localized modification provides attachment capability at specific points while preserving the overall structural strength of the shaft.
Data Source
AI summary
A filament wound composite fibre reinforced polymer shaft comprising helical wound fibres, the shaft having at least one hole perpendicular to an axis of the shaft; wherein fibre paths of the helical wound fibres divert around the hole. The hole can be used as an attachment point to connect the shaft to other parts, e.g. by means of a pin passed directly through the hole. The amount of metal used in this type of connection can be significantly reduced compared to using metal end fittings, thus greatly reducing cost and weight of the whole system. Fibres are diverted around the hole rather than the hole being cut through the fibres which would reduce the strength of the shaft as a whole. By diverting the fibres around the hole, the fibres retain their load bearing properties and the strength of the shaft is maintained even in the presence of the hole.