Shape Memory Alloy Eddy Current Probe for Complex Surfaces

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Solution Overview

Problem

Conventional non-destructive testing methods face challenges in inspecting complex surface geometries and accessing restrictive areas due to limitations in probe design and flexibility.

Innovation Solution

A conforming eddy current test probe utilizing a shape memory alloy that can be actuated to conform to the surface of a test object, eliminating the need for external actuators and allowing for manipulation into difficult-to-reach locations, featuring a flexible substrate with eddy current coils and a shape memory alloy that reverts to a pre-programmed shape for precise surface adaptation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional rigid probe is used for non-destructive testing, then the probe structure is simple and easy to manufacture, but it cannot conform to complex surface geometries or access restrictive areas

Engineering Contradiction:

Improvesurface conformityVSAvoidprobe structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The probe employs a shape memory alloy (SMA) element that can dynamically change its shape between a compressed state for insertion and an expanded state for surface conformity. This dynamic transformation allows the probe to adapt to complex geometries without requiring multiple rigid configurations or complex mechanical articulation mechanisms.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The probe utilizes temperature-induced phase transformation of the shape memory alloy to change its physical parameters. By heating the SMA element above its transformation temperature, the probe transitions from a compressed low-profile state to an expanded conforming state, enabling surface adaptation through parameter change rather than mechanical complexity.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If external actuators are used to change probe shape, then the probe can adapt to different surfaces, but the device complexity and size increase

Engineering Contradiction:

Improveshape transformationVSAvoidactuator system

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The shape memory alloy element serves as a self-contained actuator that transforms the probe shape through its inherent phase transformation properties. The SMA element responds to thermal input by automatically changing shape without requiring external motors, hydraulic systems, or mechanical linkages, thereby eliminating complex actuator systems while maintaining shape transformation capability.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The probe replaces traditional mechanical actuation systems with a thermally-driven shape memory alloy mechanism. Instead of using motors, gears, or linkages to change probe shape, the invention uses the SMA's temperature-dependent phase transformation to directly achieve shape change, substituting a simple thermal field for a complex mechanical actuation system.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If the probe is made flexible to access difficult locations, then accessibility improves, but the probe may deform permanently and lose structural integrity

Engineering Contradiction:

ImproveaccessibilityVSAvoidstructural integrity

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The probe is pre-configured with a shape memory alloy element that has been trained to return to a specific predetermined shape after deformation. This preliminary programming of the SMA's memory function ensures that even when the probe is compressed or bent during insertion, it will reliably return to its intended operational shape, maintaining structural integrity and consistent performance.

Inventive Principle:

Principle #10Preliminary action

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 effective inspection of previously inaccessible areas with precise surface conformity, enhancing the ability to detect defects and improve scanning efficiency by adapting to complex geometries without permanent deformation or the need for external actuators.

Implementation Method 1

a shape memory alloy that reverts to a pre-programmed shape when heated

Methodology Applied

Scientific EffectShape memory alloy effect: Shape Memory Alloy

Implementation Method 2

eddy current coils configured as spiral traces on a flexible printed circuit board substrate

Methodology Applied

Scientific EffectEddy current: Eddy Currents

Implementation Method 3

eddy current test probe utilizing a shape memory alloy that can be actuated to conform to the surface of a test object

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS10895554B2Flexible eddy current test probe using a shape-memory alloy for surface conformance

Publication Date: 2021.01.19 SOUTHWEST RES INST

AI summary

A conforming eddy current testing (ECT) probe for performing eddy current testing when placed on the surface of a test object. An eddy current array is fabricated on a flexible substrate. A shape metal alloy (SMA) piece is manufactured to have an original shape that conforms to the surface of the test object, and then affixed to the substrate. The SMA piece has as much or more flexibility than the substrate, so that it can be manipulated into position. Just prior to testing, the SMA piece is actuated to revert to its original shape.