Laser vibrometer condition assessment of cemented materials using wavelet synchro-squeezed transform

Piotr Wiciak,Maria Anna Polak,Giovanni Cascante,G.L Golewski

doi:10.1051/matecconf/202032301003

Abstract

Current non-destructive ultrasonic techniques (NDT) are based mostly on wave velocity analysis. While current techniques can identify severe damage, they fail to detect early deterioration. Therefore, the proposed method, based on the propagation of surface waves, takes into account not only changes in wave velocity but also changes in wave attenuation. In practical/field applications, access to a structure is often limited to one side only (i.e. concrete slabs, vacuum building walls). Thus, surface wave analysis is a natural solution. To improve the reliability of wave attenuation measurements, responses of ultrasonic transducers are measured using a high-frequency Doppler laser vibrometer. Firstly, the ultrasonic transducer is characterized using the laser vibrometer. Then, based on the sensitive frequency ranges, response signals measured for the cemented sand specimen are analyzed, and the relative attenuation index based on spectral energy is proposed. The method is further improved using the wavelet synchro-squeezed transform.

Highlights

The condition of structural materials in civil engineering applications is critical for the safety of structures
In practical/field applications, access to a structure is often limited to one side only
The knowledge of the transmitted signal is critical in the analysis of ultrasonic data. It helps to understand the frequency content of the signals, but it can help to identify the wavelength of waves penetrating the tested material

Summary

Introduction

The condition of structural materials in civil engineering applications is critical for the safety of structures. The most popular ultrasonic non-destructive techniques, used for the evaluation of the structural material condition, are based on wave velocity and the information about the frequency content is not utilized. Wave velocity techniques fail when the goal is to detect damage in the early stages. To overcome this issue, new techniques based on phase velocity and material damping [1,2] were developed. New techniques based on phase velocity and material damping [1,2] were developed These techniques need proper identification of a frequency content transferred to a tested material.

Methods

Results

Conclusion