Composite Shaft Ribbed Internal Supports for Torque Buckling
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Solution Overview
Problem
Composite drive shafts face challenges in balancing thin walls for weight efficiency with sufficient buckling resistance, as thin walls may not adequately resist torque-induced buckling, which can lead to premature damage.
Innovation Solution
A composite shaft design incorporating a plurality of internal support members made from molded plastic, featuring circular end walls and radially extending ribs, which are joined together to enhance torsional stiffness and axial bending flexibility, while maintaining a lightweight structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the wall thickness of the composite shaft is reduced to decrease weight, then weight efficiency is improved, but buckling resistance deteriorates
Solution Approach 1:
The internal structure of the composite shaft is segmented into multiple discrete reinforcement elements (fiberglass rods, carbon fiber rods, or aramid rods) arranged in specific patterns within the wall thickness. These segmented reinforcement elements provide localized buckling resistance without requiring increased overall wall thickness, thus maintaining weight efficiency while improving strength.
Solution Approach 2:
The shaft employs a composite structure combining the base polymer-matrix fiber-reinforced material with additional discrete fiber reinforcement elements (fiberglass, carbon fiber, or aramid). This multi-material composite approach allows the thin-walled shaft to achieve enhanced buckling resistance through the synergistic combination of different fiber materials with complementary mechanical properties.
2Strength
If internal support members are added to improve buckling resistance, then buckling resistance is improved, but device complexity increases
Solution Approach 1:
The discrete fiber reinforcement elements serve multiple functions: they provide buckling resistance, enhance torsional stiffness, and maintain axial strength. This multi-functionality allows a single reinforcement system to address multiple performance requirements simultaneously, reducing the need for separate structural components and thereby limiting the increase in device complexity.
Solution Approach 2:
The reinforcement elements are integrated within the thin-walled shaft structure as embedded fibers rather than as separate internal support members. This integration approach maintains the thin-walled design while providing the necessary structural support, avoiding the complexity of assembling and installing separate internal support components.
Data Source
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Figure 3A~3G
AI summary
A composite shaft includes a shaft body formed from a plurality of polymer impregnated fiber-reinforced material layers having an annular outer surface and an annular inner surface defining a passage. A plurality of internal support members (70) extend along the passage. Each of the plurality of internal support members 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, a first end (84), an opposing second end (86), and a circular end wall (88) arranged at one of the first end and the opposing second end (86).