Shape-Memory Bushing Assembly for Damage-Free Installation

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Solution Overview

Problem

Existing bushing installation methods, particularly for shape-memory bushings with flanges, often result in damaged bushings or structures due to non-uniform expansion rates and require complex installation techniques like shrink-fit or brute force, limiting their use.

Innovation Solution

A bushing assembly featuring a cylindrical body made from smart materials, such as shape-memory alloys or polymers, that selectively expands to secure within a washer flange in an interference fit, using complementary configurations and notches/projections for precise alignment and minimal damage, with a seal for fluid-tight integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If shape-memory bushings are used for installation, then the bushing can be securely installed in an interference fit, but the bushing cannot be easily removed or replaced

Engineering Contradiction:
Improveinstallation securityVSAvoidbushing replaceability
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The bushing utilizes shape-memory material that can dynamically change its expansion state based on temperature. During installation, the bushing is heated to expand and secure in the interference fit. For replacement, the bushing is cooled to contract and allow removal. This dynamic state change enables both secure installation and easy replacement without compromising either requirement.

Inventive Principle:
Principle #15Dynamics

2Ease of manufacture

If traditional shrink-fit or brute force installation methods are used for flanged bushings, then the bushing can be installed, but the bushing or structure may be damaged

Engineering Contradiction:
Improveinstallation feasibilityVSAvoiddamage to bushing or structure
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The installation process utilizes temperature as a controllable parameter to change the physical state of the shape-memory bushing. By heating the bushing to a specific temperature range, it expands to an austenitic state that allows easy installation into the flanged opening. After installation, cooling returns it to a contracted martensitic state, securing it without damage. This parameter-based control eliminates the need for damaging brute force methods.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If shape-memory technology is applied to flanged bushings, then uniform expansion can be achieved, but different parts of the bushing expand at different rates

Engineering Contradiction:
Improveexpansion uniformityVSAvoidinstallation complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The flanged bushing is divided into two separate components: a cylindrical bushing body and a flange. The bushing body, made of shape-memory material, expands uniformly when heated. The flange remains separate during the expansion process and is attached afterward. This segmentation allows the shape-memory material to expand uniformly without the complexity of coordinating expansion of integrated flanged structures.

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables predictable and damage-free installation of bushing assemblies with flanges, allowing for easier repair and replacement while maintaining structural integrity and fluid-tight seals.

Implementation Method 1

The cylindrical body is fabricated from a smart material that is configured to selectively expand when at least a portion of the body is positioned within the washer opening

Methodology Applied
Scientific EffectShape-memory effect: Shape Memory Alloy

Data Source

PatentEP2748475B1Bushing assembly and method of assembling same
Publication Date: 2015.12.09 THE BOEING CO
  • EP2748475B1 patent drawingFigure 1~2
  • EP2748475B1 patent drawingFigure 3~4
  • EP2748475B1 patent drawingFigure 5~6

AI summary

A bushing assembly (100) includes a washer (110) that includes an opening (130) defined therethrough. A cylindrical body (120) includes a first end (230) that is sized to be inserted within the washer opening and an opposite second end (240). The cylindrical body (120) is fabricated from a smart material that is configured to selectively expand when at least a portion of the body is positioned within the washer opening (130).