Our EU project, INSTRUCTIVE came to an end with the closing of 2018. We have achieved all of our milestones and deliverables; and, now have 51 (=60-9) days to submit our final reports. We have already presented the technical contents of those reports to representatives of our sponsors in a final review meeting just before the Christmas break. I think that they were pleased with our progress; our findings certainly stimulated debate about how to move forward and implement the new technologies – lots of new questions that we did not know we should be asking when we started the project.
We are also disseminating the key results more publicly because this is an obligation inherent with receiving public funding for our research; but also, because I see no purpose in advancing knowledge without sharing it. During the course of the project we have given research updates at three conferences and the papers/abstracts for these are available via the University of Liverpool Repository [#1, #2 & #3]. And, we are in the process of producing three papers for publication in archived journals.
However, the real tangible benefit of the project is the move to next stage of development for the technology supported by a new project, called DIMES, that started on January 1st, 2019. The aim of the DIMES project is to develop and demonstrate systems with the capability to detect a crack or delamination in a metallic or composite structure, and the potential to be deployed as part of an on-board structural health monitoring system for passenger aircraft. In other words, the INSTRUCTIVE project has successfully demonstrated that a new philosophy for monitoring damage in aerospace structures, using disturbances to the strain field caused by the damage, is at least as effective as traditional non-destructive evaluation (NDE) techniques and in some circumstances provides much more sensitivity about the initiation and propagation of damage. This has been sufficiently successful in the laboratory and on aircraft components in an industrial environment that is worth exploring its deployment for on-board monitoring and the first step is to use it in ground-based tests.
There will be more on DIMES as the project gets underway and updates on its progress will replace the twice-yearly ones on INSTRUCTIVE.
A few months I took this series of photographs while waiting to board a trans-Atlantic flight home. First, a small ladder was placed in front of the engine. Then a technician arrived, climbed onto the ladder and spread a blanket on the cowling before kneeling on it and spinning the fan blades slowly. He must have spotted something that concerned him because he climbed in, lay on the blanket and made a closer inspection. Then he climbed down, rolled up the blanket and left. A few minutes later he returned with a colleague, laid out the blanket and they both had a careful look inside the engine, after which they climbed down, rolled up the blanket put it back in a special bag and left. Five or ten minutes later, they were back with a third colleague. The blanket was laid out again, the engine inspected by two of them at once and a three-way discussion ensued. The result was that our flight was postponed while the airline produced a new plane for us.
Throughout this process it appeared that the most sophisticated inspection equipment used was the human eye and a mobile phone. I suspect that the earlier inspections were reported by phone to the supervisor who came to look for himself before making the decision. One of the goals of our current research is to develop easy-to-use instrumentation that could be used to provide more information about the structural integrity of components in this type of situation. In the INSTRUCTIVE project we are investigating the use of low-cost infra-red cameras to identify incipient damage in aerospace structures. Our vision is that the sort of inspection described above could be performed using an infra-red camera that would provide detailed data about the condition of the structure. This data would update a digital twin that, in turn, would provide a prognosis for the structure. The motivation is to improve safety and reduce operating costs by accurate identification of critical damage.
The Southwest airplane accident last week has been initially attributed to a fatigue crack in a fan blade in the engine. One of the reasons that this an extremely rare event is the enormous research effort that has been expended on the design, testing and maintenance of the engines and the airframe. It’s an ongoing research effort to address the trilemma of aircraft that are safe, sustainable and low cost to build and operate. In collaboration with Strain Solutions Limited, we are in the last year of a three-year project called INSTRUCTIVE which is funded by the Clean Sky 2 programme of the European Commission [see ‘Instructive report and Brexit‘ on March 29th, 2017]. The focus of the research is the development of techniques for use in the aerospace industry to detect the initiation of cracks in the airframe before the crack is visible to the naked eye [see ‘Instructive update‘ on October 4th, 2017]. Laboratory-based techniques exist with this capability and the objective is to transfer the technology to the industrial scale and environment – initially in structural tests performed as part of the design and certification process and perhaps later as part of inspections of aircraft in service. So far, we have moved from the small components reported in the update posted in October, to a chunk of aircraft fuselage in our lab and we are preparing to participate in a test being conducted by Airbus later this year.
We are also planning a knowledge exchange workshop on ‘Real-time damage tracking in engineering structures’ on November 21st, 2018 at the University of Liverpool’s London campus. The one-day workshop is being organised in collaboration with the British Society for Strain Measurement. More details to follow – it will be free!
Six months ago I wrote about our EU research project, called INSTRUCTIVE, and the likely consequences of Brexit for research [see my post: ‘Instructive report and Brexit‘ on March 29th, 2017]. We seem to be no closer to knowing the repercussions of Brexit on research in the UK and EU – a quarter of EU funding allocated to universities goes to UK universities so the potential impacts will hit both the UK and EU. Some researchers take every opportunity to highlight these risks and the economic benefits of EU research; for instance the previous EU research programme, Framework Programme 7, is estimated to have created 900,000 jobs in Europe and increased GDP by about 1% in perpetuity. However, most researchers are quietly getting on with their research and hoping that our political leaders will eventually arrive at a solution that safeguards our prosperity and security. Our INSTRUCTIVE team is no exception to this approach. We are about half-way through our project and delivered our first public presentation of our work at the International Conference on Advances in Experimental Mechanics last month. We described how we are able to identify cracks in metallic structures before they are long enough to be visible to the naked eye, or any other inspection technique commonly used for aircraft structures. We identify the cracks using an infra-red camera by detecting the energy released during the formation and accumulation of dislocations in the atomic structure that coalesce into voids and eventually into cracks [see my post entitled ‘Alan Arnold Griffith‘ on April 26th, 2017 for more on energy release during crack formation]. We can identify cracks at sub-millimetre lengths and then track them as they propagate through a structure. At the moment, we are quantifying our ability to detect cracks forming underneath the heads of fasteners [see picture] and other features in real aerospace structures; so that we can move our technology out of the laboratory and into an industrial environment. We have a big chunk of airplane sitting in the laboratory that we will use for future tests – more on that in later blog posts!