Context The project EMERGE fits into the overall problem of postoperative complications following the total knee arthroplasty (the implantation of a total knee replacement). These complications resulting from various surgical and non-surgical factors may shorten the lifespan of this implant and consequently lead to revision surgery. Given that the current designs of total knee replacement compensate for the absence of the anterior and posterior cruciate ligaments by their shapes more or less congruent, the stabilization functionality of the collateral ligaments can be ensured by the surgical technique. However, despite the fact that the cutting guides allow the surgeon to properly align the prosthetic components of total knee replacement with respect to the mechanical axis, there is no computerized system allowing him to perfectly balance the collateral ligaments as has been reported in several postoperative studies. Moreover, even if the collateral ligaments are perfectly balanced at the time of surgery, it is not necessary that the balance will remain perfect in the years following this surgery. This is due to the fact that the morphology of the patient including age, weight, and lifestyle will considerably change with time. Therefore, the functionality of total knee replacement becomes suboptimal; which may sometimes lead to a revision surgery (9% at 10 years, 16% at 15 years, and 22% at 20 years). These proportions will result in a considerable number of revision surgeries considering the increase in life expectancy on one hand, and the growing demand for this type of surgery from younger and active patients on the other hand. Solution To meet this issue, a new generation of knee implant, able to compensate for the variations of functionalities by its adjustable and adaptive shape, will be proposed. Developing such a self-powered implantable device involves ensuring its power supply and its control using embedded sensors. Innovative and multidisciplinary project aims to minimize the significant number of revision surgeries by implementing the first generation of dynamic implants. Objective of this program The goal of this program is to develop a new generation of instrumented knee implant comprising (1) an integrated power generator, (2) a power conditioning system (3) a telemetry system, and (4) an actuator for fin-tuning the implant shape in the postoperative period. A preclinical validation will be performed in order to validate the proof-of-concept. The ratio risk/benefit will be evaluated in a clinical study that is not part of this program in order to determine the delivered medical service.

Electro-Active Polymers are new soft materials, which may undergo large reversible deformations (tens of percent strains) under an applied electric field, in contrast to piezo-electric ceramics whose maximum strain is limited to a fraction of percent. This field currently experiences a huge interest in academic laboratories over the world. One motivation relies on the unique properties of these systems, that could find applications in “soft robotics”, where the challenge is to design highly compliant machines that are able to move in topographically complex environments or to manipulate brittle objects. Nevertheless, only very few products based on Electro-Active Polymers have reached the industrial level. The aim of SMArT project is to develop new strategies for innovative applications in soft mechatronics based on a study of dielectric elastomers: structures with adjustable rigidity for vibration control (harnessing electro-mechanical instability); mechanical energy harvesting systems; and in the long run, electrofluidic devices for medical use as well as characterization devices for biological soft tissues. Developing such systems however requires a more fundamental understanding of electro-elastic interactions as well as the complex multiscale properties of polymer networks and the interplay of bulk and interfacial forces. The project meets the objectives of the 3rd axis (Materials and methods) of the Challenge “stimuler le renouveau industriel” of the ANR. It aims to stimulate industrial renewal by creating new electroactive polymeric materials whose principle is based on the multiplicity of physical scales and functions. The project will implement various innovative functionalization processes and surface treatments to obtain controlled conductivity and wetting properties. The project aims at producing new electromechanical functions by playing with the geometry, the topology, the structural organization and interfacial gradients of properties. The project is organized along four complementary work packages. The first of them will constitute a fundamental basis for the other tasks: - WP 0: Fabrication, modeling and characterization - WP 1: Studying and harnessing Electro-mechanical instabilities for new applications. - WP 2: Energy harvesting and sensing applications. - WP 3: Probing and controlling interfacial properties - WP 4: A prototype to demonstrate the most promising applications Preliminary experiments have already been conducted in the two experimental groups and lead us to spot out several technological or theoretical bottlenecks. This experience brought us to build a complementary team dedicated to the success of the project. The project leaders are specialists of non-linear mechanics and physical chemistry. Experimental activities will be completed by theoretical and numerical works. Students with experimental backgrounds are already working within the team and a postdoctoral research fellow will be in charge of the numerical simulations of the project. Cedrat Technologies is a leading company in mechatronics and will bring all its experience in actuation and sensing electronics, mechanical tests and engineering design. It will also play a key role by selecting and then transforming proofs of concept into demonstration prototypes, bringing a first step towards a future industrial development of these new technologies.

In the framework of the transition toward condition-based maintenance, connected objects deployment is reinventing monitoring processes. This is extremely relevant with respect to corrosion which represents a significant issue in aeronautics. In 2016 the annual corrosion cost for commercial aircraft fleet operated by European airlines was estimated to 2.2 B$. Anticipating corrosive conditions ahead of time is estimated to generate between 15% and 35% of cost savings. Specific coatings are used to prevent corrosion but remain limited in their ability to completely avoid structural corrosion specially in harsh operational environment. To detect such damages, nondestructive testing methodologies for corrosion consist in “on ground” regular visual inspection which does not allow detection of the corrosion damage premises, precise quantification of corrosion damage size, and prediction of the remaining useful life of associated parts. Adding on board native connectivity to aircraft metallic parts appears as the key technology to safely face this issue while minimizing costs and environmental impact. This goes through embedding ultrasonic sensors into aeronautic airframe parts and providing them with on board structural health monitoring algorithms and digital twins able to improve operational availability without compromising safety. COQTEL is the joint multidisciplinary effort of French experts in structural health monitoring (PIMM lab), ultrasonic hardware designing (CTEC SME), aerospace metallic parts coating (RESCOLL SME), and corrosion and fatigue modelling (I2M lab) to face this challenge. It proposes to move from classical “on ground” non-destructive testing to “on board” condition-based maintenance by embedding ultrasonic sensors in aircraft metallic parts and by developing and validating dedicated hardware, digital twins, and algorithms endowing airframe parts with built-in corrosion monitoring functionalities. The ambition of COQTEL is to detect the premises of corrosion, to quantify the size of in situ corrosion damages, and to be able to predict associated remaining useful life in order to participate in the revival of the aeronautical industry and the SMEs accompanying it by providing them with a proof of concept of the use of intelligent aeronautical structures for predictive maintenance.