Plasma Transducer for Acoustic Emission in Extreme Environments

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Solution Overview

Problem

Conventional piezoelectric crystals used in acoustic-emission sensors have frequency-dependent sensitivity, limited temperature range, and are susceptible to neutron irradiation, making them inadequate for predicting structural failure in extreme environments.

Innovation Solution

A system utilizing a transducing medium with pressure-dependent electrical resistivity, comprising immersed electrodes in an ionized gas within an electrically non-conducting envelope, coupled with a high-pass filter to isolate the transduced acoustic signal from applied voltage, allowing for frequency-independent sensitivity and operation in extreme temperatures and neutron fluxes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a piezoelectric crystal is used as the transducing element, then the sensitivity at resonance frequency is improved, but the frequency independence and temperature range are worsened

Engineering Contradiction:

ImprovesensitivityVSAvoidfrequency independence

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent replaces the piezoelectric crystal (mechanical/electrical transducer) with a plasma-based transducing medium. The plasma's electrical resistivity changes in response to acoustic pressure waves, providing a different physical mechanism for transduction that avoids the resonance frequency limitations of piezoelectric materials. This substitution enables frequency-independent sensitivity across ultrasonic frequency ranges.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the operating parameters by using plasma density and electrical resistivity as the transduction mechanism instead of piezoelectric material properties. The plasma's electrical resistivity varies with acoustic pressure, and by controlling plasma parameters (density, temperature, composition), the system achieves broad frequency response and extended temperature operation without the narrow resonance peak limitation of crystals.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If a piezoelectric crystal is used, then the transduction performance is improved, but the resistance to neutron irradiation and extreme temperatures is worsened

Engineering Contradiction:

Improvetransduction performanceVSAvoidresistance to neutron irradiation

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent substitutes piezoelectric crystals with a plasma-based transducing medium that is inherently more resistant to neutron irradiation and extreme temperatures. Plasma, being an ionized gas, does not suffer from the same radiation damage mechanisms as crystalline structures, maintaining transduction performance in harsh nuclear environments where piezoelectric materials degrade.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If the crystal is tuned to a resonant frequency above the acoustic-emission frequency range, then the frequency independence is improved, but the sensitivity is significantly reduced

Engineering Contradiction:

Improvefrequency independenceVSAvoidsensitivity

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The invention replaces the resonance-based piezoelectric transduction mechanism with a plasma-based mechanism where acoustic pressure directly modulates electrical resistivity. This substitution eliminates the need for resonance tuning, allowing the system to maintain high sensitivity across a broad frequency range without requiring the crystal to be operated above its resonant frequency.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 solution provides a transducer with high and frequency-independent sensitivity, capable of operating in extreme temperatures and neutron irradiation environments, effectively predicting structural failure by sensing acoustic emissions without signal distortion.

Implementation Method 1

a transducing medium with pressure-dependent electrical resistivity, comprising immersed electrodes in an ionized gas

Methodology Applied

Scientific EffectPressure-dependent electrical resistivity: Piezoresistive Effect

Implementation Method 2

a high-pass filter coupled to the transducing medium, the high-pass filter configured to isolate the transduced signal from the applied voltage

Methodology Applied

Scientific EffectHigh-pass filtering: Filter (electronic)

Data Source

PatentUS11161147B2System and method for acoustic to electronic transduction

Publication Date: 2021.11.02 THE TRUSTEES OF PRINCETON UNIV

AI summary

According to various embodiments, a system for acoustic to electronic transduction is disclosed. The system includes a transducing medium configured to convert a received acoustic signal into a transduced electronic signal when a voltage is applied. The system further includes a high-pass filter coupled to the transducing medium, the high-pass filter configured to isolate the transduced signal from the applied voltage.