Non-destructive investigation of anisotropic materials using air-coupled ultrasound

Project Description:

This project aims to develop database for automation of a broadband, single-sided, contact-free, ultrasound-based non-destructive-testing method for defect characterization. Preliminary own experiments have shown, that laser-based ultrasound (US) generation combined with an innovative laser-based, air-coupled, high-fidelity optical microphone for detection performs well in transmission mode testing. This approach is based on the Local Acoustic Resonance Spectroscopy (LARS) technique [Grosse, Jüngert et al. 2018] and a derivative of the known Air-Coupled Ultrasonic Testing (ACUT) using piezoelectric transducers.

First results from single-sided ACUT measurements using a piezoelectric transducer for excitation and an optical microphone for detection in combination with Machine-Learning using a Convolutional Neural Network were promising. Expanding LARS from transmission to single-sided measurement mode and implementing machine learning for data analysis should yield highly interesting results with new possible applications in the industry. For basic materials research the new technique enables for the investigation of components with complex geometry and significant heterogeneity.

The objective of this project is a deeper analysis of LURS data and proceeding of database of training material that will be used for ML algorithms and further automation of the control process.

Start: 01.10.2023

Duration: 2 years

Funding: DFG – Walter Benjamin Programm

TUM Participants: Chair of Non-Destructive Testing: Dr. Olga Popovych