Composite Shaft End Forming for Metal-Free Load Transfer
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Solution Overview
Problem
Interfacing composite shafts with other components is challenging due to reduced bearing strength, requiring metal parts that add weight and cost, which detracts from the weight and cost savings of using Polymer Matrix Composites (PMCs).
Innovation Solution
A method for forming a composite fibre-reinforced polymer shaft with a hollow cylindrical portion and a shaped end portion moulded from a cylindrical shape prior to curing, eliminating the need for metal end connections by using fibre-reinforced polymer for a lighter, stronger connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal parts are used to interface with composite shafts, then connection strength is improved, but weight and cost increase
Solution Approach 1:
The patent applies composite materials by forming the end portion of the shaft from fibre-reinforced polymer composite material that integrates with the main shaft body. This eliminates the need for separate metal connection parts while maintaining structural strength through the continuous fibre reinforcement that extends from the main shaft into the end portion, thereby reducing weight while preserving connection capability.
Solution Approach 2:
The patent merges the shaft body and connection end portion into a single integrated composite structure. The fibres that form the main cylindrical shaft extend across from the main shaft into the end portion, creating a unified load-path structure that eliminates the need for separate metal fittings and reduces overall component count and weight.
2Strength
If metal parts are used to interface with composite shafts, then connection strength is improved, but cost increases
Solution Approach 1:
The end portion is manufactured from the same fibre-reinforced polymer composite material as the main shaft using continuous fibre placement techniques. This eliminates the need for separate metal part manufacturing, machining, and assembly operations, thereby reducing manufacturing complexity and cost while maintaining connection strength through integrated fibre continuity.
Solution Approach 2:
By combining the shaft body and end portion into a single monolithic composite structure formed in one manufacturing process, the patent eliminates multiple manufacturing steps including separate metal part fabrication, surface preparation, bonding, or mechanical fastening operations, thereby reducing overall manufacturing cost and complexity.
3Shape
If fibres are wound directly onto a shaped mandrel, then end portion shape is achieved during winding, but manufacturing complexity increases
Solution Approach 1:
The patent segments the mandrel into two parts: a simple cylindrical mandrel for the main shaft and a separate mould for the end portion. This allows the main shaft to be wound using conventional cylindrical winding techniques while the end portion shape is achieved through a separate moulding operation, thereby simplifying the winding process while still achieving the desired end portion geometry.
Solution Approach 2:
The patent applies preliminary action by first forming the end portion from a hollow cylindrical shape before final curing. This preliminary shaping step allows the use of simple cylindrical winding for the main shaft, followed by a separate moulding operation to achieve the final end portion geometry, thereby avoiding the complexity of direct shaped mandrel winding while ensuring proper fibre orientation and load transmission.
Data Source
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AI summary
A composite fibre-reinforced polymer shaft (20) having a hollow cylindrical portion (21) and a shaped end portion (9), the shaped end portion (9) being moulded from a hollow cylindrical shape prior to curing. By moulding the end portion (9) from a hollow cylindrical shape, the shaped end portion (9) can be formed into a desired shape easily and quickly from a shape that is easy and efficient to produce by normal winding techniques. The cylindrical shape is preferably an extension of the hollow cylindrical portion (21) that forms the rest of the shaft (20) such that the fibres that form the main cylindrical shaft extend across from the main cylindrical shaft into the end portion (9), thus providing excellent load transmission properties along the shaft (20).