Non-destructive estimation of coating layer thickness based on sweep frequency photo acoustic guided wave technique

A system for non-destructive estimation of coating layer thickness based on sweep frequency photo acoustic guided wave technique, comprising:

• a sensor module, and
• an analysis module comprising a one or more hardware processors(s), an Input/Output interface(s), a memory, and a database, wherein the one or more hardware processors are configured by the instructions to:
• generate a plurality of photoacoustic guided waves from a plurality of samples, via one or more hardware processors, by irradiating the plurality of samples by an intensity modulated Continuous Wave (CW) laser diode at a pre-defined angle and a pre-defined sweep frequency, wherein the plurality of samples absorb laser radiation and undergoes thermoelastic expansion and during relaxation the plurality of samples releases the plurality of photoacoustic guided waves having a same frequency as excited frequencies, wherein the plurality of guided photoacoustic waves are received by an ultrasound sensor in contact with the plurality of samples via a coupling medium and then the plurality of photoacoustic guided waves are acquired by a Vector Network Analyzer (VNA), wherein the plurality of photoacoustic guided waves exhibit a maximum amplitude near a resonance frequency of the plurality of samples, and wherein the plurality of samples is associated with a known-thickness parameter;
• determine a frequency spectrum of the plurality of photoacoustic guided waves generated from the each of the plurality of samples, via the one or more hardware processors, based on a frequency spectra determination technique;
• determine the resonance frequency from the frequency spectrum, via the one or more hardware processors, based on a sweep frequency photoacoustic guided wave technique, wherein the sweep frequency is a narrow band of frequencies, wherein a sweep frequency acoustic signal is sensed by the ultrasound sensor and acquired by the Vector Network Analyzer, wherein the VNA plots a magnitude of the sweep frequency photoacoustic signal at different frequencies to obtain the frequency spectrum from the each of the plurality of samples;
• and
• plot a calibration curve based on the resonance frequency, via the one or more hardware processors, wherein the calibration curve associates the resonance frequency of each of the plurality of samples is associated with the known-thickness parameter of each of the plurality of samples.

One or more non-transitory machine-readable information storage mediums for non-destructive estimation of coating layer thickness based on sweep frequency photo acoustic guided wave technique comprising one or more instructions which when executed by one or more hardware processors cause:

• generating a plurality of photoacoustic guided waves from a plurality of samples, by irradiating the plurality of samples by an intensity modulated Continuous Wave (CW) laser diode at a pre-defined angle and a pre-defined sweep frequency, wherein the plurality of samples absorb laser radiation and undergoes thermoelastic expansion and during relaxation the plurality of samples releases the plurality of photoacoustic guided waves having a same frequency as excited frequencies, wherein the plurality of photoacoustic guided waves are received by an ultrasound sensor in contact with the plurality of samples via a coupling medium and then the plurality of photoacoustic guided waves are acquired by a Vector Network Analyzer (VNA), wherein the plurality of photoacoustic guided waves exhibit a maximum amplitude near a resonance frequency of the plurality of samples, and wherein the plurality of samples is associated with a known-thickness parameter;
• determining a frequency spectrum of the plurality of photoacoustic guided waves generated from the each of the plurality of samples, based on a frequency spectra determination technique;
• determining the resonance frequency from the frequency spectrum, based on a sweep frequency photoacoustic guided wave technique, wherein the sweep frequency is a narrow band of frequencies, wherein a sweep frequency acoustic signal is sensed by the ultrasound sensor and acquired by the Vector Network Analyzer, wherein the VNA plots as magnitude of the sweep frequency photoacoustic signal at different frequencies to obtain the frequency spectrum from each of the plurality of samples;
• and
• plotting a calibration curve based on the resonance frequency, wherein the calibration curve associates the resonance frequency of each of the plurality of samples is associated with the known-thickness parameter of each of the plurality of samples.