Super-sensitivity in resistive and capacitive strain sensing
Advanced composite materials are a key enabling technology for new solutions in energy production, transportation and storage. It is critical to develop monitoring techniques that are viable for a large scale/distributed sensing, which can inform us about the critical condition of the structures, localize and identify their degradation mechanism.
Capacitive sensors are usually preferred for local strain sensing. Yet, the sensitivity of such sensors is guided only by the geometrical change, with a gauge factor close to one. Achieving high sensitivity appeared quite challenging and with limited success so far.
We present here a new concept where high piezoresistive electrodes are used to drastically improved the gauge factor of capacitive sensors.
First, we present our initial work on super high gauge factor in piezoresistive sensing, using fragmented conductive films. This works allows to build electrode with large change in resistance under stretch, that is an enabling component of our capacitive technology.
Second, we present our capacitive technology, the starting point of which is a classical parallel capacitor equipped with highly resistive electrodes. In such a case, the system behaves as a transmission line, resulting in a limited penetration of the interrogation signal over the sensor length. The innovation here is to make this high resistive strain-dependent by introducing well-chosen and designed patterns of cracks inside the electrodes.
This design results in a strain and frequency dependent capacitance, that unlock the potential of capacitive sensing.
Prof. Gilles Lubineau is Professor of Mechanical Engineering and Associate Dean of the Faculty, PSE Division at KAUST. As a founding KAUST Faculty, he leads the Laboratory for Mechanics of Composites for Energy and Mobility.
Current research interests include: integrity at short and/or long-term of composite materials and structures, inverse problems for the identification of constitutive parameters, multi-scale coupling technique, multifunctional materials and modeling, nano and multifunctional materials and devices, soft robotics, and flexible sensors. He collaborates with many industries from a variety of sectors including the Energy sector, the Transportation sector or the Consumer electronics sector.
Before joining KAUST, Prof. Lubineau was a faculty member at the École Normale Supérieure of Cachan, and a non-resident faculty member at the École Polytechnique, France. He also served as a visiting researcher at UC-Berkeley. Following his "aggregation" in theoretical mechanics, Prof. Lubineau earned a Ph.D. degree in Mechanical Engineering and an HDR from École Normale Supérieure de Cachan (ENS-Cachan). He has authored over 200 journal papers. His work covers very wide expertise from Material Science to Composite Engineering and Computational Mechanics as testified by the diversity of his publications in journals such as Advanced Materials, Journal of the Mechanics of Physics of Solids, Scientific Reports, Composite Structures, Composites Part A, Macromolecules, Langmuir, Small, Nanoscale, etc. He received the Daniel Valentin award recognizing his accomplishments in the science of composite materials. He is also a board member for various journals, including the International Journal of Damage Mechanics. Prof. Lubineau is an elected Member of the European Academy of Sciences and Arts.