Segmented Shape Memory Alloy Cable for Thermal Response

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Solution Overview

Problem

Conventional structural cables are static and lack adaptability, facing challenges such as poor fatigue performance, high costs, and sluggish thermal response due to scaling issues with shape memory alloy (SMA) materials when used in larger forms.

Innovation Solution

A cable comprising a plurality of longitudinally inter-engaged shape memory alloy wires, offering improved flexibility, fatigue performance, and thermal response through a compact, high-force actuator design, adaptable for use as both an actuator and dampening element, with integrated sensors and controllers for smart functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional SMA material is used in large-section bars, then structural strength is improved, but thermal response time becomes sluggish due to poor heat transfer through the section

Engineering Contradiction:

Improvestructural strengthVSAvoidthermal response time

Core Design Contradiction:

StrengthVSSpeed

Solution Approach 1:

The patent divides the large-section SMA structural element into multiple smaller wires or strands, each with sufficient surface area-to-volume ratio for rapid thermal response. These segmented wires are bundled together to achieve the required structural strength, thus resolving the contradiction between strength and thermal response speed.

Inventive Principle:

Principle #1Segmentation

2Strength

If conventional SMA material is used in large-section bars, then structural strength is improved, but manufacturing complexity increases due to difficulties in controlling quench rates

Engineering Contradiction:

Improvestructural strengthVSAvoidmanufacturing complexity

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent segments the large structural element into multiple smaller wires that can be manufactured using conventional wire drawing and quenching processes. This avoids the manufacturing complexity associated with large-section bar quenching while maintaining structural strength through the bundled configuration.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the geometric parameters from large cross-section bars to multiple small cross-section wires, fundamentally altering the surface area-to-volume ratio and enabling conventional manufacturing processes to be used effectively.

Inventive Principle:

Principle #35Parameter changes

3Strength

If conventional SMA material is used in large-section bars, then structural strength is improved, but cost increases significantly

Engineering Contradiction:

Improvestructural strengthVSAvoidcost

Core Design Contradiction:

StrengthVSQuantity of substance

Solution Approach 1:

The patent uses multiple small-diameter SMA wires instead of a single large bar. This segmentation allows more efficient use of SMA material, reducing the total quantity required while maintaining equivalent structural strength through the combined effect of multiple strands.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent creates a composite structure combining multiple SMA wires, potentially with different properties or combined with other materials, to achieve the required structural strength more cost-effectively than using a single large-section SMA bar.

Inventive Principle:

Principle #40Composite materials

4Stability of the object's composition

If conventional cables are used, then structural stability is maintained, but adaptability is lost as they are static members incapable of tuning

Engineering Contradiction:

Improvestructural stabilityVSAvoidadaptability

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent incorporates shape memory alloy wires that can dynamically change their mechanical properties in response to thermal or stress stimuli, enabling the cable to transition between different stiffness states and provide adaptive structural behavior while maintaining stability.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent utilizes the phase transition characteristics of shape memory alloy wires, which can reversibly transform between martensite and austenite phases, enabling the cable to change its mechanical properties adaptively while maintaining structural integrity.

Inventive Principle:

Principle #36Phase transitions

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

The SMA wire cable provides enhanced flexibility, compact spooling, and efficient energy absorption and dissipation, addressing scaling concerns and cost issues while enabling adaptive structural applications with faster thermal response and improved durability.

Implementation Method 1

the SMA wires are in the austenitic phase, where energy is absorbed and dissipated superelastically

Methodology Applied

Scientific EffectSuperelasticity: Pseudoelasticity

Implementation Method 2

at least two of the wires comprise shape memory alloy material

Methodology Applied

Scientific EffectShape memory effect: Shape Memory Alloy

Data Source

PatentUS8272214B2Shape memory alloy cables

Publication Date: 2012.09.25 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A cable adapted for use as an actuator, adaptive structural member, or damper, includes a plurality of longitudinally inter-engaged and cooperatively functioning shape memory alloy wires.