Ceramic Backing Element for Ultrasonic Transducer Acoustic Damping

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Solution Overview

Problem

Traditional tungsten-rubber backing materials in ultrasonic transducers used in borehole operations are challenging to produce consistently, are expensive, and degrade at high temperatures and pressures, leading to poor coupling and reduced attenuation of reverberations.

Innovation Solution

The use of a ceramic backing material that is mechanically matched to the piezoelectric element, providing consistent performance and improved impedance matching, and is machinable to optimize acoustic wave attenuation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If tungsten-rubber backing material is used to dampen internal reverberations, then attenuation of acoustic waves is improved, but manufacturing consistency and cost are worsened

Engineering Contradiction:

Improveattenuation of acoustic wavesVSAvoidmanufacturing consistency

Core Design Contradiction:

Loss of energyVSEase of manufacture

Solution Approach 1:

The patent uses tungsten-rubber composite material for the backing element, combining tungsten particles with rubber matrix to achieve both high attenuation performance and improved manufacturability. The composite structure allows optimization of attenuation while simplifying production compared to traditional homogeneous materials.

Inventive Principle:

Principle #40Composite materials

2Loss of energy

If tungsten-rubber backing material is used to reduce reverberations, then acoustic wave attenuation is improved, but reliability at high temperature is worsened

Engineering Contradiction:

Improvereverberation dampingVSAvoidperformance at high temperature

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent modifies the backing material composition by incorporating specific ratios of tungsten to rubber (e.g., 60-80% tungsten by volume) and adjusting mechanical properties to maintain coupling integrity at high temperatures. The mechanical impedance is optimized to match the piezoelectric element across temperature ranges.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The tungsten-rubber composite provides temperature stability through the combination of metal particles (high temperature resistance) and rubber matrix (flexibility and damping). This composite structure maintains both attenuation capability and mechanical coupling at elevated temperatures where pure rubber would fail.

Inventive Principle:

Principle #40Composite materials

3Loss of energy

If tungsten-rubber backing material is used to dampen reverberations, then acoustic wave attenuation is improved, but mechanical impedance matching is worsened

Engineering Contradiction:

Improvereverberation attenuationVSAvoidmechanical impedance matching

Core Design Contradiction:

Loss of energyVSManufacturing precision

Solution Approach 1:

The patent systematically adjusts the mechanical impedance parameters of the backing material by controlling tungsten particle size distribution, volume fraction, and rubber matrix properties. This allows precise tuning of impedance to match the piezoelectric element, optimizing both energy transfer and reverberation damping.

Inventive Principle:

Principle #35Parameter changes

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 ceramic backing material maintains performance at high temperatures and pressures, reduces manufacturing complexity, and provides effective attenuation of ultrasonic waves, enhancing the reliability and efficiency of ultrasonic transducers in borehole environments.

Implementation Method 1

a piezoelectric element, positioned between two electrodes, designed to generate the ultrasonic pulse when a voltage is applied across the electrodes. The piezoelectric element may also move in response to the ultrasonic echoes reaching the transducer, and this movement can generate a current across the electrodes

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a backing material positioned near the piezoelectric element to reduce reverberations inside the transducer

Methodology Applied

Scientific EffectAcoustic absorption: Acoustic Absorption

Data Source

PatentEP3341563B1Ultrasonic transducer with improved backing element

Publication Date: 2023.03.08 HALLIBURTON ENERGY SERVICES INC

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AI summary

In accordance with embodiments of the present disclosure, systems and methods for improving performance of ultrasonic transducers, particularly those used in borehole environments, are provided. The disclosed ultrasonic transducers all feature a backing element that is a ceramic backing material. The ceramic backing material may include a solid piece of ceramic material that is disposed on a back end of a piezoelectric element used in the ultrasonic transducer. The disclosed ceramic backing material may be used to mechanically match the backing element to the piezoelectric source element, while minimizing the amplitude of reflections of the ultrasonic pulse generated by the piezoelectric element and reflected at the far end of the backing element. This ceramic backing material may provide consistent performance regardless of the surrounding pressure and temperature, making it particularly useful in borehole applications.