On Zoom: https://kaust.zoom.us/meeting/register/tJYtcOirqT0iHdONNV8kiZm8u7Vs8XWjWD1C

Abstract

The use of acoustic waves to detect and/or locate damage within materials and structures revealed to be promising in different fields (aeronautics, civil engineering, oil industry, etc.). This has given rise to various applications based on the use of one or several sensors to optimize the interaction of the acoustic waves emitted within the structure under test. In addition, passive ultrasonic acoustic methods have also been used to investigate the different damage mechanisms that can be created when materials are submitted to dynamic or quasi-static stresses. The first part of this talk is based on the use of active transient acoustic waves in order to characterize cracks created within polymer-based composites in standing wave conditions. Standing wave tests performed on concrete and composite samples will first be presented. Then, transient wave measurements based on the propagation of guided waves will be shown in order to locate and image the created damages within composite structures. The second part will present the passive acoustic characterization known as acoustic emission (AE). The latter is revealed to be highly adapted to monitor in real time materials and structures by considering the AE-features, which can be either analyzed by means of physical considerations (geophysics/seismology) or through their time/frequency waveform characteristics. Results will be focused on composites and concrete beams in order to monitor the created cracks and understand the created damage mechanisms.

References can be found through the following link: Google Scholar

Bio

Education

• Ph.D., Materials Science, National Institute of Applied Sciences at Lyon (France), MATEIS (Non Destructive Evaluation, Multifunctional Materials), Advisors: J-C. Baboux & R . El Guerjouma, 2005 o Nonlinear Acoustics Applied to the Ultrasonic Characterization of Damage in Heterogeneous Materials and Determination of their Remaining Lifetime.
• M.S.*, Condensed Matter Physics, USTHB (Algeria), Evaluation of 2nd and 3rd order Elastic Constants with Ultrasound, 2001
• B.S., Solid State Physics, 1997

* This thesis is called Magister: it takes 1 theoretical year and after an exam we need around 3 years to defend the Magister thesis.

Expertise

Dr. Bentahar is interested in the acoustic characterization of materials. In particular his work focuses on developing non-destructive evaluation methods to increase the sensitivity to micro events that happen within heterogeneous materials. Dr. Bentahar was a post-doctoral fellow in Catholic University of Leuven (Belgium) before working for the National Scientific Research Center (France) in the medical ultrasound field. Since 2008, Dr. Bentahar is a permanent researcher in the Laboratory of Acoustics of Le Mans. He is developing nonlinear acoustic techniques to detect and characterize damage in polymer and metal composites as well as concrete. In particular, his current work is focusing on the quantification of the nonlinear acoustic indicators (classical and hysteretic) in terms of the released elastic energy during the damaging of materials in order to understand the micromechanisms that are responsible of the macroscopic observations. Dr. Bentahar has led several research projects in collaboration with different companies such as Airbus, Mecachrome, DAHERSOCATA, etc.

Dr Bentahar is also interested in acoustic emission, imaging techniques (air-coupled, phased array, EMATs, etc.), Signal Processing and Guided waves.