National projects
Embedded optical fibers in cement materials for ultrasonic imaging and monitoring (2022 - 2025).
The benefits of using an embedded optical fiber (FO) for monitoring are numerous, including its limited size and durability in challenging conditions, such as salinity and radioactivity, as well as its broadband nature that makes it suited to various scales. Despite these benefits, there are still improvements that can be made in both the sensors, electronics, and data processing.
The FO-US project aims to:
1/ design and validate FO for multi-trace ultrasonic measurements at frequencies of several hundred kHz.
2/ develop algorithms that consider the limitations of FO for 2D-3D active imaging with volume waves and passive imaging with guided waves, in line with two clearly identified industrial needs.
3/ demonstrate the transferability of this new technology to various application fields through laboratory validation experiments of imaging algorithms, prior to a field test.
The PROMETHEUS project aims to introduce a methodological and technological solution, based on 3D radar technology, for mapping the underground network infrastructure in urban areas. The project is structured around five work packages (WPs) involving five partners: G. Eiffel University, Cerema, Clermont University, Logiroad company, and the water and l'agence de l’eau et de l’assainissement of the Saint-Quentin metropolitan area (external partner).
WP1 focuses on the state of the art and specifications for cataloging and selecting significant indicators to describe pipelines and their environment. WP2 is dedicated to developing a hybrid approach (Deep Learning DL & Matrix Pencil Method MPM) for automatic pipeline detection and classification applied to raw data acquired from a multi-antenna GPR device. WP3 focuses on a hybrid approach using pre-processed GPR data (3D migration and waveform inversion) followed by DL learning. The final WP4 deals with the constitution of different databases on two test sites of G. Eiffel University and several real sites proposed by the Saint-Quentin Metropolitan Area.
This research proposal will allow local authorities to access all information characterizing their road resources. To carry out this project, the five partners will be supported by two doctoral students and several Master's interns.
Monitoring of New and Existing Infrastructure using Embedded Sensor to evaluate indicators necessary for their sustainable management (2021-2024)
For a sustainable and secure management of civil engineering structures and to increase their service life, facility managers need comprehensive and quantitative information about the ongoing evolution of performance indicators, particularly the strength, modulus, porosity, and water content of concrete. The goal of the SCaNING project is to develop a systematic approach to monitoring the health of new or existing reinforced concrete structures. This includes validating embedded sensors (electrical, electromagnetic, and ultrasonic), processing measurement data and extracting relevant observables that are decoupled from key influencing factors, and converting the observables into diagnostic indicators. These embedded sensors also offer the advantage of being able to calibrate and thus enhance the accuracy of non-destructive evaluations performed on the surface of the facility, creating a quantitative map of the entire structure.
Two labs of Université Gustave Eiffel are contributing to this project : MAST/LAMES, which coordinates the project, and GERS/GeoEND, which focuses on the study and design of embedded electromagnetic and ultrasonic sensors.
Improvement of soils with rigid inclusions : Dynamic and seismic loads.
The technique of reinforcing compressible soils using vertical Rigid Inclusions (RI) is widely used in France and abroad. This composite foundation technique combining deep and superficial elements was initially developed for embankment structures (for transportation infrastructure), but it is now being used for wind turbines and industrial buildings (such as logistics platforms), housing or office buildings (less than 4-5 floors), schools, hospitals, etc. It is thus present all over the territory, impacting the choice of foundations for constructions and transportation linear structures (roads and railways), affecting citizens in their daily life and mobility in a subtle but real way.
Two specific aspects of the behavior of soil masses reinforced with rigid inclusions are addressed in the ANR component of the ASIRI+ Project (a PN component is being developed in parallel):
- Under dynamic loads: Modification of the speed of wave propagation in a medium with periodic inclusions
- Under seismic loads: Inertial and Kinematic effects
In both cases, remarkable experimental equipment will be used (the Non-Contact Ultrasonic Measurement Bench (MUSC) and the Geotechnical Centrifuge equipped with the Earthquake simulator), and their results will be compared with numerical simulations.
Improving knowledge of complex fractured media and multi-parameter inversion (2019-2023).
The French road network primarily consists of national roads, most of which were completed around thirty to forty years ago. Road surface defects are mainly caused by cracks, subsoil defects (non-debouching horizontal cracks such as interface detachment or non-debouching vertical cracks) that can occur well before visible degradation occurs on the pavement surface. The evaluation and monitoring of the structural damage of pavements have become major issues for the sustainable management of the road network. The detection, localization and characterization of these non-debouching cracks (horizontal or vertical) are important diagnostic elements that influence the implementation of maintenance and management policies. The challenges of this project are to carry out an early detection of these cracks, to locate them with great accuracy and to characterize them geometrically with high-frequency non-destructive evaluation and control (NDE) methods in the radar frequency bands (geophysical radar and Ground-Based SAR). On the one hand, the project aims to implement new high-resolution processing methods with geophysical radar and GB-SAR, and on the other hand, to use broader frequency bands than those currently used, with one innovation being the extension of GB-SAR to this "pavement" application.
The MecaWave research group was established in January 2018. It brings together research on waves in solids, from the persective of physical acoustics, theoretical mechanics and applied mathematics. MecaWave structures common activities in these disciplines within Section 9 of CNRS, on a national scale, primarily involving laboratories attached to INSIS, as well as several laboratories of INSMI and INSU. It is organized into 4 working groups, each driven by two moderators: 1. Effective dynamics of microstructured media (thin layers, generalized continuous media, foundations of metamaterials, etc.), 2. Nonlinear waves in solids (waves and cracks, slow dynamics in damaged media, "adjustable" media, etc.), 3. Mechanical waveguides (trapped modes, open guides, etc.), 4. Inverse problems (non-destructive control, microstructure optimization, etc.). The main action of the GdR MecaWave is to promote scientific exchange by organizing thematic days and conferences. For each working group, moderators will organize an annual thematic day, with a possible specific focus. Over the duration of the GdR, 3 conferences of 5 days will be organized, involving all participants. Director: Bruno Lombard (DR CNRS), Assistant Directors: Fabien Treyssède (DR Université Gustave Eiffel), Kim Pham (MDC ENSTA)