Start Date

2016 12:00 AM

Description

We describe a novel calibration technique of air-coupled transducers for nonlinear ultrasonic measurements through homogenous, isotropic media. Our calibration technique combines laser interferometrywith a model-based approach to derive a relationship between received force at the transducer face and the measured output voltage. Conventional nonlinear ultrasonic measurement techniques have relied upon contact receiving transducers that are heavily influenced by contact conditions (e.g. inconsistent coupling) and laser interferometers that are prohibitively expensive and rely on a mirror-finished surface or complicated optics. Air-coupled transducers are significantly less expensive than laser interferometers and are robust relative to surface conditions, but current calibration techniques such as self-reciprocitymethods pose fundamentally challenging problems. We describe a method to experimentally deduce a transfer function |H(ω)| that can be used to predict surface displacements of fundamental and second harmonic wave components with the aid of proper acoustic field modelling in the pursuit of measuring the absolute nonlinearity parameter, β.

Language

en

File Format

application/pdf

Share

COinS
 
Jan 1st, 12:00 AM

Calibration of Air-Coupled Transducers for Absolute Nonlinear Ultrasonic Measurements

We describe a novel calibration technique of air-coupled transducers for nonlinear ultrasonic measurements through homogenous, isotropic media. Our calibration technique combines laser interferometrywith a model-based approach to derive a relationship between received force at the transducer face and the measured output voltage. Conventional nonlinear ultrasonic measurement techniques have relied upon contact receiving transducers that are heavily influenced by contact conditions (e.g. inconsistent coupling) and laser interferometers that are prohibitively expensive and rely on a mirror-finished surface or complicated optics. Air-coupled transducers are significantly less expensive than laser interferometers and are robust relative to surface conditions, but current calibration techniques such as self-reciprocitymethods pose fundamentally challenging problems. We describe a method to experimentally deduce a transfer function |H(ω)| that can be used to predict surface displacements of fundamental and second harmonic wave components with the aid of proper acoustic field modelling in the pursuit of measuring the absolute nonlinearity parameter, β.