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Joining the dots

Six months ago, I wrote about ‘Finding DIMES’ as we kicked off a new EU-funded project to develop an integrated measurement system for identifying and tracking damage in aircraft structures.  We are already a quarter of the way through the project and we have a concept design for a modular measurement system based on commercial off-the-shelf components.  We started from the position of wanting our system to provide answers to four of the five questions that Farrar & Worden [1] posed for structural health monitoring systems in 2007; and, in addition to provide information to answer the fifth question.  The five questions are: Is there damage? Where is the damage? What kind of damage is present? How severe is the damage?  And, how much useful life remains?

During the last six months our problem definition has evolved through discussions with our EU Topic Manager, Airbus, to four objectives, namely: to quantify applied loads; to provide condition-led/predictive maintenance; to find indications of damage in composites of 6mm diameter or greater and in metal to detect cracks longer than 1mm; and to provide a digital solution.  At first glance there may not appear to be much connection between the initial problem definition and the current version; but actually, they are not very far apart although the current version is more specific.  This evolution from the idealised vision to the practical goal is normal in engineering projects.

We plan to use point sensors, such as resistance strain gauges or fibre Bragg gratings, to quantify applied loads and track usage history; while imaging sensors will allow us to measure strain fields that will provide information about the changing condition of the structure using the image decomposition techniques developed in previous EU-funded projects: ADVISE, VANESSA (see ‘Setting standards‘ on January 29th, 2014) and INSTRUCTIVE.  We will use these techniques to identify and track cracks in metals [2]; while for composites, we will apply a technique developed through an EPSRC iCASE award from 2012-16 on ‘Full-field strain-based methods for NDT & structural integrity measurement’ [3].

I gave a short briefing on DIMES to a group of Airbus engineers last month and it was good see some excitement in the room about the direction of the project.  And, it felt good to be highlighting how we are building on earlier investments in research by joining the dots to create a deployable measurement system and delivering the complete picture in terms of information about the condition of the structure.

Image: Infra red photograph of DIMES meeting in Ulm.

References

  1. Farrar & Worden, An introduction to structural health monitoring, Phil. Trans. R Soc A, 365:303-315, 2007
  2. Middleton, C.A., Gaio, A., Greene, R.J. & Patterson, E.A., Towards automated tracking of initiation and propagation of cracks in aluminium alloy coupons using thermoelastic stress analysis, Nondestructive Evaluation, 38:18, 2019.
  3. Christian, W.J.R., DiazDelaO, F.A. & Patterson, E.A., Strain-based damage assessment of accurate residual strength prediction of impacted composite laminates, Composites Structures, 184:1215-1223, 2018.

The INSTRUCTIVE and DIMES projects have received funding from the Clean Sky 2 Joint Undertaking under the European Union’s Horizon 2020 research and innovation programme under grant agreements No. 685777 and No. 820951 respectively.

The opinions expressed in this blog post reflect only the author’s view and the Clean Sky 2 Joint Undertaking is not responsible for any use that may be made of the information it contains.

Stopped in Lime Street

It is a late, slightly muggy, summer afternoon and I am sitting at the window in the last carriage of a train waiting for it to leave Liverpool for London.  So far, it has been a busy day with meetings in the morning at the University’s facility at Daresbury followed by a couple on the main campus before I walked down to Lime Street station.  I stopped for a bite to eat as I travelled from Daresbury to Liverpool; but I am hungry again, so I have a sandwich that I bought in the station.  However, I don’t like to unpack and start eating until the train starts moving, just in case I am on the wrong train or we have to change trains.  Finally, the train starts to move and as it builds up speed I reach for my sandwich.  Suddenly it stops.  My carriage has not even reached the end of the platform.  Station staff appear outside my window talking into their radios.  What’s happened?  Did the train hit someone?  I thought there was a small thud just before we stopped.  But the station staff seem unflustered.  Wouldn’t there be more urgency about their movements if there was a casualty?  We sit in silence for ten minutes before the train starts to move again and the train manager announces that someone pulled the emergency handle because they decided that wanted to get off the train. Why did they want to get off the train?  Did they realise they were trapped on the train to London with someone who was pursuing them?  Was it a police officer who realised that their quarry had jumped off the train just before it set off?  Or, have I been reading too many Eric Ambler stories (see ‘The Mask of Dimitrios‘ or ‘Journey into Fear‘) involving train journeys across Europe?  Maybe it was someone who just decided that they didn’t want to go London after all and didn’t care about inconveniencing several hundred people or paying the fine for improper use of the emergency handle.  But that seems unlikely too or perhaps not…  I contemplate these options as the train accelerates towards London and I munch my sandwich.  It reminds me of a quote from Gillian Tett (in the FT Weekend on June 17/18, 2017) about people believing they have a ‘God-given right that they should be able to organise the world around their personal views and needs instead of quietly accepting pre-packaged options’.

Only the name of the airport changes

The conference that I attended last week was in Reno, Nevada and, on my way to it, I stopped over in Dayton, Ohio and visited the US Air Force Research Laboratory to present the results from our research project supported by their European Office of Aerospace Research & Development (EOARD).  The journey from Liverpool to Dayton, via Manchester and Altanta airports, took 17 hours; however, that was short compared to the journey from Dayton to Reno, via Chicago and San Francisco airports, which took 24 hours door-to-door or rather hotel-to-hotel.  ‘Only the name of the airport changes’ is a quote from Italo Calvino describing the city of Trude in his book ‘Invisible Cities‘; but it also described how I felt looking out from my window seats at successive airports over the four days that I travelled from Liverpool to Reno.

We arrived at Dayton airport at 5am for a 7am flight to be told that it was cancelled and we were re-booked on a flight leaving at 5.18pm.  We tried to re-rent the rental car that we had just returned but were told every car was booked; so, we were stuck in Dayton airport for 12 hours.  Your perspective of time changes in these circumstances.  At 5am with nothing much to do, 12 hours seemed like infinity; but at 5pm when we were about to board our flight, the same 12 hours seemed short – almost as if we had only arrived at the airport an hour or so earlier.  Augustine observed that our consciousness is based on memory and anticipation such that time is entirely present in our minds as memory and as anticipation.  While Aristotle considered time to be the measurement of change.  Hence, since I was anticipating no change during my 12 hours of waiting, my perception of time was of it passing very slowly.  Whereas, when I was boarding my flight 12 hours later, my memory was of having done the same things that I would usually have done while waiting for a flight [reading and editing draft manuscripts from my research group]; and hence my perception of the elapsed 12 hours was compressed into the usual 2-hour period spent at an airport prior to a flight.  The apparent unchanging view out of the plane’s window, both in flight and, to a lesser extent, on the ground also tended to distort my perception of the passage of time.

Sources:

Italo Calvino, Invisible Cities, Penguin Vintage Classics, 1997.

Carlo Rovelli, The Order of Time, Penguin, 2019.

 

Feedback is a gift

In academic life you get used to receiving feedback, including plenty of negative feedback when your grant proposal is declined by a funding agency or your manuscript is rejected by the editor of a journal.  We are also subject to annual performance reviews which can be difficult if all of your proposals and manuscripts have been rejected.  So, how should we respond to negative feedback?

The Roman philosopher, Marcus Aurelius is credited with the saying ‘Everything we hear is an opinion, not a fact’, which perhaps implies we should not take the negative feedback too seriously, or at least we should look for some evidence.

Tasha Eurich has suggested we should mine it for insight and harness it for improvement but without incurring collateral damage to your self-confidence.  He recommends a five-point approach, based on empirical evidence:

  1. Don’t rush to react
  2. Gather more evidence
  3. Find a harbinger
  4. Don’t be a lonely martyr but engage in dialogue
  5. Remember that change is not the only option; you can accept your weaknesses, share them and work around them.

If you are the one giving the negative feedback then it is worth remembering the stages of response to bad news are denial, anger, bargaining, depression and acceptance.  Hopefully, the feedback will not induce the full range of response but, when it does, you should not be surprised.

See earlier posts on giving [‘Feedback on feedback‘ on June 28th, 2017] and receiving student feedback [‘Deep long-term learning‘ on April 28th, 2018].

 

Source: Tasha Eurich, ‘The right way to respond to negative feedback’, HBR, May 31st, 2018.