Lamb Wave Thickness Measurement Using Single Transducer
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Solution Overview
Problem
Conventional methods for structural health monitoring using ultrasonic transducers to detect changes in material thickness are inaccurate due to difficulties in precisely positioning transducers on the top and bottom surfaces of materials.
Innovation Solution
A system and method utilizing Lamb waves, where an electrical driving signal is transmitted to generate Lamb waves, and propagation parameters are estimated to calculate the thickness of a material, allowing for accurate thickness measurement without the need for precise transducer placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultrasonic transducers are placed on top and bottom surfaces to detect Lamb waves, then thickness measurement capability is achieved, but positioning precision deteriorates due to difficulty in precise alignment
Solution Approach 1:
The patent extracts the thickness measurement function from the conventional dual-transducer system and implements it using a single transducer that generates and receives Lamb waves from one location. This eliminates the need for precise positioning between top and bottom transducers while maintaining thickness measurement capability through analysis of the received wave signal characteristics.
Solution Approach 2:
The single transducer performs multiple functions: it generates Lamb waves and receives the reflected waves for thickness measurement. This multi-functional approach replaces the conventional two-transducer system, eliminating positioning errors while achieving the same measurement objective through signal analysis of the round-trip wave propagation.
2Measurement precision
If transducers are positioned on opposite surfaces for accurate thickness detection, then measurement capability is improved, but system complexity increases due to alignment requirements
Solution Approach 1:
The patent removes the complex alignment system by extracting the thickness measurement function to a single-transducer configuration. The transducer is placed on only one surface, eliminating the need for complex alignment mechanisms between opposite surfaces while maintaining accurate thickness detection through Lamb wave signal analysis.
Solution Approach 2:
The single transducer serves itself by both generating and receiving the Lamb waves. This self-service approach eliminates the need for separate transmitting and receiving transducers on opposite surfaces, thereby reducing system complexity and alignment requirements while maintaining measurement accuracy.
3Measurement precision
If conventional ultrasonic methods are used with transducer placement, then thickness monitoring is possible, but measurement reliability deteriorates due to placement offsets
Solution Approach 1:
The patent extracts the measurement function from the flawed dual-transducer placement system and implements it using a single transducer on one surface. This eliminates the source of reliability problems (placement offsets) while maintaining consistent and accurate thickness measurements through analysis of the Lamb wave signal characteristics.
Solution Approach 2:
Instead of physically placing transducers on both surfaces (which introduces alignment errors), the system uses a single transducer that effectively 'copies' the measurement capability by generating waves that traverse the thickness and return. The received signal contains all necessary information for accurate thickness measurement without requiring physical presence on both surfaces.
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 accurate estimation of material thickness over time, effectively monitoring structural health by analyzing Lamb wave properties, reducing inaccuracies associated with transducer placement offsets.
Implementation Method 1
Wave generating component 103 may be any type of electromechanical transducer that is operable to convert electrical energy to mechanical energy, a non-limiting example of which includes a piezoelectric device
Implementation Method 2
Receiving component 105 is operable to detect a wave propagated from wave generating component 103
Implementation Method 3
If the particle vibrates in it direction that is normal with the surface of the material and in the wave propagation direction, then the wave is a Lamb wave
Data Source
AI summary
A method includes: transmitting, via a signal generator, an electrical driving signal, the electrical driving signal having a mean square error; transmitting, via a wave generating component, a Lamb wave, the Lamb wave having many different modes; estimating, via an estimating component, a propagation parameter associated with the Lamb wave; and estimating, via an estimating component, a thickness of a material.