Piezocomposite Lamb Wave Transducer for Wide-Angle Beam Steering

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Solution Overview

Problem

Existing ultrasonic transducers for non-invasive measurements face challenges in controlling the direction of sound beams over a broad angular range with sufficient amplitude, particularly in level measurements where the liquid surface is not constant, requiring a transducer with a broad bandwidth for effective angular tunability.

Innovation Solution

The use of a piezocomposite actuator in the ultrasonic Lamb wave transducer, which emits acoustic radiation at various frequencies to control the emission direction of ultrasonic Lamb waves, allowing for wide angular variability and high frequency bandwidth, achieved by combining piezoceramic materials with polymers to decrease the quality factor and enhance acoustic coupling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional ultrasonic transducer is used, then the device structure is simple, but the angular variability of the sound beam is limited

Engineering Contradiction:

Improveangular variabilityVSAvoidtransducer structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent employs a piezocomposite actuator combining piezoceramic materials with polymers to create a transducer that achieves broad bandwidth and wide angular variability. The composite structure allows the device to emit acoustic radiation at multiple frequencies, enabling effective steering of sound beams over a broad angular range while maintaining sufficient amplitude, thus resolving the contradiction between adaptability and device complexity.

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If the frequency bandwidth is narrow, then the transducer structure is simple, but the angular tunability is insufficient

Engineering Contradiction:

Improveangular tunabilityVSAvoidfrequency bandwidth

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The piezocomposite actuator inherently provides broad frequency bandwidth due to the combination of piezoceramic materials with polymers. This composite structure enables the transducer to operate effectively across a wide frequency range, which directly translates to wide angular tunability through the relationship between frequency and sound beam angle, thus resolving the contradiction between angular tunability and frequency bandwidth.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent utilizes frequency as a controllable parameter to adjust the emission direction of ultrasonic Lamb waves. By varying the frequency within a broad bandwidth, the transducer can steer the sound beam across a wide angular range, effectively resolving the contradiction between angular tunability and frequency bandwidth through parameter optimization.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If the quality factor is high, then the energy storage is good, but the angular variability is reduced

Engineering Contradiction:

Improveangular variabilityVSAvoidquality factor

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The combination of piezoceramic materials with polymers in the piezocomposite actuator decreases the quality factor compared to pure piezoceramic materials. This reduction in quality factor allows for broader bandwidth operation and wider angular variability, while the composite structure maintains sufficient energy storage capability through the synergistic properties of the constituent materials, thus resolving the contradiction between angular variability and energy storage.

Inventive Principle:

Principle #40Composite materials

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

This solution enables efficient steering of sound beams over a wide range, optimizing energy reception and allowing for accurate liquid level measurements by varying the frequency to adjust the radiation angle, thereby improving the angular variability and amplitude of the emitted acoustic beam.

Implementation Method 1

at least one piezocomposite actuator configured to control the emission direction of the ultrasonic Lamb wave by emitting acoustic radiation at frequencies that are appropriate for generating ultrasonic Lamb waves

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

The transmitter emits an ultrasound wave as a primary wave into the vessel wall so that a part of the primary Lamb wave leaks from the vessel wall into the liquid in form of a pressure wave

Methodology Applied

Scientific EffectAcoustic radiation: Acoustic Radiation Pressure

Data Source

PatentUS11826781B2Ultrasonic transducer for non-invasive measurement

Publication Date: 2023.11.28 ABB (SCHWEIZ) AG

AI summary

An ultrasonic Lamb wave transducer for non-invasive measurement and for emitting and/or receiving an ultrasonic Lamb wave pulse, an emission and a reception of the ultrasonic Lamb wave having an emission direction and a reception direction, respectively, the ultrasonic Lamb wave pulse being defined by at least one parameter, includes: at least one piezocomposite actuator for controlling the emission direction of the ultrasonic Lamb wave by emitting acoustic radiation at frequencies that are appropriate for generating ultrasonic Lamb waves.