Composite Shaft Internal Supports for Thin-Wall Buckling Resistance
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Solution Overview
Problem
Existing composite shafts face challenges in achieving both thin walls for reduced weight and enhanced buckling resistance, particularly under torque loads, which can lead to premature shaft damage due to unstable load transfer and deformation.
Innovation Solution
A composite shaft design incorporating a plurality of internal support members made from molded plastic with varying geometries and joined by rods or fasteners, providing structural reinforcement while maintaining lightweight flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the wall thickness of the composite shaft is increased to improve buckling resistance, then the buckling resistance is improved, but the weight of the shaft increases
Solution Approach 1:
The internal support structure is divided into multiple discrete support members distributed along the shaft length, with multiple support members in axial overlap. This segmentation provides buckling resistance throughout the shaft without requiring uniform wall thickness increases, maintaining weight efficiency while improving structural stability.
Solution Approach 2:
The invention combines polymer-matrix fiber-reinforced composite material for the shaft wall with plastic support members forming an internal support structure. This composite approach allows the thin-walled shaft to achieve enhanced buckling resistance through the internal plastic supports while maintaining the weight advantages of thin composite walls.
2Weight of moving object
If the wall thickness is reduced to decrease weight, then the weight is reduced, but the buckling resistance deteriorates
Solution Approach 1:
Multiple discrete support members are distributed along the shaft, creating localized reinforcement zones. This allows the shaft to maintain thin walls for weight reduction while providing targeted buckling resistance where needed, avoiding the penalty of uniformly thick walls.
Solution Approach 2:
The plastic support members act as intermediary elements between the internal and external surfaces of the thin-walled shaft. These intermediaries provide the necessary structural support for buckling resistance without requiring the walls themselves to be thicker, thus maintaining weight efficiency.
3Strength
If internal support members are added to improve buckling resistance, then the buckling resistance is improved, but the device complexity increases
Solution Approach 1:
The support members feature undulated or corrugated geometries that provide high buckling resistance through geometric stiffness rather than material quantity. This allows effective buckling resistance with simpler, more compact internal structures compared to traditional solid rods, reducing overall device complexity.
Solution Approach 2:
The support members incorporate undulations and corrugations that utilize three-dimensional geometric complexity to achieve buckling resistance. This dimensional approach provides high structural efficiency with relatively simple linear elements, avoiding the need for complex multi-component assemblies.
Data Source
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Figure 3A~3G
AI summary
A composite shaft (50) includes a shaft body (54) formed from a plurality of polymer impregnated fiber-reinforced material layers having an annular outer surface (56) and an annular inner surface (58) defining a passage (60). A plurality of internal support members (70) extend along the passage (60). Each of the plurality of internal support members (70) includes a support body (80) formed from molded plastic having an outer surface (82) that abuts the annular inner surface (92) of the support body (80), a first end (84), an opposing second end (86), and a circular end wall (88) arranged at one of the first end (84) and the opposing second end (86).