Current and Future Possibilities for Embedded Fibre Optic Sensing
To answer the question “Can a dream of self-sensing composite material become reality?” the Organizers of the CFK-Valley Stade Convention talked to Dr. Eli Voet from Com&Sens bvba. Mr Voet is since 2012 managing associate and project engineer at Com&Sens for projects related to instrumentation and condition monitoring of composite materials. His lecture is one of more than 20 top notch presentations about latest developments in the technologies, processes and construction methods of composite lightweight construction both in research and practice. The intended audience includes almost 400 participants – international experts from the composite industry: Researchers, developers, designers, engineers, managers.
Com&Sens (stands for Composites & Sensing) is a Spin-off company of Ghent University and is specialized in applying fibre optic sensors to monitor composite structures. Mr Voet will talk about the concept of self-sensing composites on the first Convention day on 16 June. Previous he gives an overview on that topic and answers the headline question. “We as Com&Sens clearly think that the “Self-Sensing Composite Material-dream” can come true! The concept of self-sensing composites is relatively easy: a part wise or fully instrumented structure gives feedback on its structural response to any applied loading condition. As such the operator or inspector is able to determine if operation is still safe, i.e. “all in the green”, or if maintenance is necessary, i.e. “orange level”. Valuable information is gathered from sensing, not only for safe operation but more important to validate currently used simulation models or even to help improve designing.” Mr Voet starts and explains continuing: “Embedded sensing moreover, provides you the free option of applying the same embedded sensor technique already during the composite fabrication process. The sensors can for instance measure the residual strain built-up happening because of shrinking effects (e.g. warping, buckling). Of course this concept of a self-sensing or smart composite is not new and exists already more than several decades. However, implementation of embedded sensor technology has been presented so far mostly on academic research -and prototyping level. In fibre reinforced plastics, embedded fibre Bragg gratings are found to be one of the most popular and reliable solutions for strain monitoring. Why? Because their absolute sensor properties, non-intrusive and small dimensions (~100 – 200µm diameter), high sensitivity and multiplexing capacity, match very well the requirements of a self-sensing composite concept. Despite of their, even growing popularity, some complexities and shortcomings are still retaining the actual take-up of this technology by the industry. It is noted already that in the past few years many of these issues are being solved in accelerated tempo and some of the issues are being solved when speaking.”
With his lecture Mr Voet will elaborate the state of the art on fibre optic sensing technology. An overview will be given of the draw-backs, possibilities and practical solutions. In addition some examples of real applications will be shown, highlighting the multidisciplinary properties of embedded fibre Bragg grating sensors, also focusing on application in difficult production processes and harsh environments.