# Numerical prediction of the piezoelectric transducer response in the acoustic nearfield using a one-dimensional electromechanical finite difference approach

## TL;DR

This paper introduces a one-dimensional finite difference model to predict the response of a piezoelectric transducer to optoacoustic pressure waves in the acoustic nearfield, facilitating better interpretation of experimental signals.

## Contribution

The study develops a simple electromechanical finite difference model that accurately predicts piezoelectric transducer responses in nearfield conditions, considering impedance variations and electromechanical coupling.

## Key findings

- Simulated transducer signals match experimental data well.
- The model effectively predicts the influence of impedance changes.
- The approach simplifies nearfield transducer response analysis.

## Abstract

We present a simple electromechanical finite difference model to study the response of a piezoelectric polyvinylidenflourid (PVDF) transducer to optoacoustic (OA) pressure waves in the acoustic nearfield prior to thermal relaxation of the OA source volume. The assumption of nearfield conditions, i.e. the absence of acoustic diffraction, allows to treat the problem using a one-dimensional numerical approach. Therein, the computational domain is modeled as an inhomogeneous elastic medium, characterized by its local wave velocities and densities, allowing to explore the effect of stepwise impedance changes on the stress wave propagation. The transducer is modeled as a thin piezoelectric sensing layer and the electromechanical coupling is accomplished by means of the respective linear constituting equations. Considering a low-pass characteristic of the full experimental setup, we obtain the resulting transducer signal. Complementing transducer signals measured in a controlled laboratory experiment with numerical simulations that result from a model of the experimental setup, we find that, bearing in mind the apparent limitations of the one-dimensional approach, the simulated transducer signals can be used very well to predict and interpret the experimental findings.