 Welcome to the presentation on pressurized structural member damage detection. This goes to some work we did together with Neostrain, with Gregor Spednarski and Jakub Niedrich. So let's not start with the summary. But Let's have an overview of the historical developments of flooded member detection. So the flood member detection is meant to detect the leakage for underwater members. It's hollow sections and well, they are filled with water if there was a crack, if there was a damage and then you can detect it. So that's the idea and originally it was developed for divers and remote operated vehicle use and then different technologies have evolved which was acoustic impact, thermal profiling, radiographic methods and ultrasonic methods and that work has been initiated or has been started in the 80s. There are some publications also in the 90s where this was developed and there was even something in the in the ICON project where the reliability of this flooded member detection was evaluated and then the well quite good detectability, 100% was determined for at least 50% water-filled members and this was, sorry, based on ultrasonic flood member detection. If there was only a little water in then the reliability or the probability of this detection decreased. So coming from the diver-based and ROV-based flooded member detection to permanently installed systems, this was proposed by researchers from the University of Manchester. There is Bertekin was there, involved very well-known lecturer. I've been taking lectures by him in 2000 when I was there. So this was this describes, I think also with the use of ultrasonics, first the detection of water-filled members under water and second then the communication is also done by ultrasonics to to get the alarm of the sensors communicated. So these approaches were specifically developed for under water detection. So if there was a part of the hollow structure like we have jackets, for instance, in the offshore area above the water you cannot detect and also not in the splash zone, which may be also quite subjected to two damages. So we have where we came across this method, but the background was that we were challenged by offshore wind turbines, by sub-structures of offshore wind turbines and we then formed a team of SHM specialists, so that is Neostrain. We had the structural design and consultants involved, the GBO and the SAFE-INFRA research group of BAM, where I'm still partly associated to that. So and we came up with we could especially that goes to Neostrain. Neostrain had the idea. We could pressurize the members and then we are able to detect damages in the complete jacket, so underwater in the splash zone and also on top of water. So that must be pressurized that the structure must be pressurized, so that the level of pressure is over the water pressure or the surrounding pressure and we could then easily monitor the pressure and detect the pressure drop, which indicates then that our structure is damaged. So we have developed here a technical concept, for instance, for this jacket structure and we sorted out here some details, for instance, the braces are welded to the legs, but there's naturally no connection, but this can be done by drilling holes in it and this was also checked for fatigue. So there is no fatigue problems. We are inducing here when we have the braces and the corner legs connected. Neostrain did quite some tests in their laboratory, so and with the concepts we progressed on the technology readiness level. So at the moment we are I think at stage four with the technology readiness level. So this means component and or system validation in laboratory environment, this is the tests we did on Neostrain did and there is pressure stability with these systems between minus 20 and 40 degrees of Celsius. This was tested, but it must be a temperature compensated. So this seems to be straight forward to be achieved and currently this technology is European patent pending. So coming to the structural performance, here it is important that RFMD or flooded member detection triggers and gives an indication in this phase where there is a true thickness crack and then either for RFMD the pressure drops because it's going outside or for a classical member detection that there is water ingress. So in this phase it can be detected, but the issue here is that we have to fulfill the leak before break condition. So in this state our structure should not fail and well, this is the main issue for the structural performance and that can be quantified. I think there's also something where we can rely on which was produced by Bertekin and his researchers. For quantifying the value of structural health monitoring where we are in the discussion phase and this is some points which came to my mind. So what we have or what we can achieve is a coverage of a complete hollow section structure and if we can completely cover it and can monitor it, we may also be able to replace inspections which are extremely costly in the offshore environment. We also, this was the technical concept, think that robust RFMD design may be possible or is possible. So in terms of long-living sensors, in terms of data normalization, this is a little easier than data normalization for maybe vibration signals and also the data transfer. Well, we are detecting then with this system relatively large defects. You've seen that in the in this slide here. So this is already a true thickness crack. So the component reliability may be low, but if you have a redundant system, the system reliability can still be high. And of course the issue the we have also to discuss is the costs of this RFMD solution. So they seemed for the concept we produced quite reasonable. So, but in the end we would need to quantify the value of RFMD and we're coming to the wish list. This would be rather a wish list of points we should further work on. So if there was a PhD student who is interested in this technology, they are very welcome to join us and we will also do efforts to go through these points and to come up with the quantification of the value of this technology. So and this is the main point I wanted to make. This was networking. We didn't even have a networking project. So yes, thank you for your attention.