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, leading to premature damage.

Innovation Solution

A composite shaft design featuring a shaft body formed from polymer-impregnated fiber-reinforced material layers with internal support members made of molded plastic, which provide additional structural integrity and resistance to buckling through specific geometries and connections, such as circular end walls and radially extending ribs, while maintaining a lightweight structure.

Engineering Contradictions & Design Principles

VSEngineering 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

Engineering Contradiction:

Improveshaft weightVSAvoidbuckling resistance

Core Design Contradiction:

Weight of moving objectVSStrength

Solution Approach 1:

The internal support members are divided into multiple discrete elements distributed along the shaft length, with each segment providing localized buckling resistance. The support members can be arranged in multiple rows and at different axial positions, creating a segmented reinforcement structure that maintains overall shaft integrity while using thinner walls

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention combines polymer-impregnated fiber-reinforced material layers with molded plastic internal support members to create a composite structure. The fiber-reinforced composite provides baseline strength while the internal support members provide additional buckling resistance, allowing the wall thickness to be reduced while maintaining overall structural performance

Inventive Principle:

Principle #40Composite materials

2Strength

If internal support members are added to improve buckling resistance, then structural integrity is improved, but device complexity increases

Engineering Contradiction:

Improvestructural integrityVSAvoidshaft structure complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The internal support members have a thin-walled molded plastic construction with circular end walls and radial ribs that provide high structural efficiency. The thin-walled design of the support members themselves keeps their individual complexity low while their collective arrangement provides comprehensive buckling resistance

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The internal support members feature circular end walls and radially extending ribs that create curved, ribbed structures. This geometry provides efficient load distribution and buckling resistance while being manufacturable through standard molded plastic processes, balancing structural performance with manufacturing simplicity

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Reliability

If multiple internal support members are used to enhance buckling resistance, then reliability is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvebuckling resistance reliabilityVSAvoidmanufacturing ease

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The internal support members are pre-formed as complete molded plastic components with all structural features (circular end walls, radial ribs, connection structures) already integrated. This preliminary formation allows for consistent quality and reliable performance while simplifying the final assembly process, as the support members can be inserted and secured without requiring complex in-situ manufacturing

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The internal support members are designed to be nested within the composite shaft structure, with each support member fitting within the hollow cylindrical space defined by the shaft walls. The support members can be arranged in concentric or staggered patterns, maximizing space utilization while maintaining manufacturing simplicity through sequential assembly

Inventive Principle:

Principle #7Nested doll (Nesting)

Data Source

PatentUS11795993B2Buckling resistant composite shaft and method of making a buckling resistant composite shaft

Publication Date: 2023.10.24 HAMILTON SUNDSTRAND CORP

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 extend along the passage. Each of the plurality of internal support members includes a support body formed from molded plastic having an outer surface that abuts the annular inner surface of the support body, a first end, an opposing second end, and a circular end wall arranged at one of the first end and the opposing second end.