Category Archives: design

Establishing fidelity and credibility in tests & simulations (FACTS)

A month or so ago I gave a lecture entitled ‘Establishing FACTS (Fidelity And Credibility in Tests & Simulations)’ to the local branch of the Institution of Engineering Technology (IET). Of course my title was a play on words because the Oxford English Dictionary defines a ‘fact’ as ‘a thing that is known or proved to be true’ or ‘information used as evidence or as part of report’.   One of my current research interests is how we establish predictions from simulations as evidence that can be used reliably in decision-making.  This is important because simulations based on computational models have become ubiquitous in engineering for, amongst other things, design optimisation and evaluation of structural integrity.   These models need to possess the appropriate level of fidelity and to be credible in the eyes of decision-makers, not just their creators.  Model credibility is usually provided through validation processes using a small number of physical tests that must yield a large quantity of reliable and relevant data [see ‘Getting smarter‘ on June 21st, 2017].  Reliable and relevant data means making measurements with low levels of uncertainty under real-world conditions which is usually challenging.

These topics recur through much of my research and have found applications in aerospace engineering, nuclear engineering and biology. My lecture to the IET gave an overview of these ideas using applications from each of these fields, some of which I have described in past posts.  So, I have now created a new page on this blog with a catalogue of these past posts on the theme of ‘FACTS‘.  Feel free to have a browse!

The disrupting benefit of innovation

Most scientific and technical conferences include plenary speeches that are intended to set the agenda and to inspire conference delegates to think, innovate and collaborate.  Andrew Sherry, the Chief Scientist of the UK National Nuclear Laboratory (NNL) delivered a superb example last week at the NNL SciTec 2018 which was held at the Exhibition Centre Liverpool on the waterfront.  With his permission, I have stolen his title and one of his illustrations for this post.  He used a classic 2×2 matrix to illustrate different types of change: creative change in the newspaper industry that has constantly redeveloped its assets from manual type-setting and printing to on-line delivery via your phone or tablet; progressive change in the airline industry that has incrementally tested and adapted so that modern commercial aircraft look superficially the same as the first jet airliner but represent huge advances in economy and reliability; inventive change in Liverpool’s Albert Dock that was made redundant by container ships but has been reinvented as a residential, tourism and business district.  The fourth quadrant, he reserved for the civil nuclear industry in the UK which requires disruptive change because its core assets are threatened by the end-of-life closure of all existing plants and because its core activity, supplying electrical power, is threatened by cheaper alternatives.

At the end of last year, NNL brought together all the prime nuclear organisations in the UK with leaders from other sectors, including aerospace, construction, digital, medical, rail, robotics, satellite and ship building at the Royal Academy of Engineering to discuss the drivers of innovation.  They concluded that innovation is not just about technology, but that successful innovation is driven by five mutually dependent themes that are underpinned by enabling regulation:

  1. innovative technologies;
  2. culture & leadership;
  3. collaboration & supply chain;
  4. programme and risk management; and
  5. financing & commercial models.

SciTec’s focus was ‘Innovation through Collaboration’, i.e. tackling two of these themes, and Andrew tasked delegates to look outside their immediate circle for ideas, input and solutions [to the existential threats facing the nuclear industry] – my words in parentheses.

Innovative technology presents a potentially disruptive threat to all established activities and we ignore it at our peril.  Andrew’s speech was wake up call to an industry that has been innovating at an incremental scale and largely ignoring the disruptive potential of innovation.  Are you part of a similar industry?  Maybe it’s time to check out the threats to your industry’s assets and activities…


Sherry AH, The disruptive benefit of innovation, NNL SciTec 2018 (including the graphic & title).

McGahan AM, How industries change, HBR, October 2004.

Massive engineering

Last month I was at the Photomechanics 2018 conference in Toulouse in France.  Photomechanics is the science of using photons to measure deformation and displacements in anything, from biological cells to whole engineering structures, such as bridges or powerstations [see for example: ‘Counting photons to measure stress‘ posted on November 18th, 2015].  I am interested in the challenges created by the extremes of scale and environmental conditions; although on this occasion we presented our research on addressing the challenges of industrial applications, in the EU projects INSTRUCTIVE [see ‘Instructive update‘ on October 4th, 2017] and MOTIVATE [see ‘Brave New World‘ posted on January 10th, 2018].

It was a small conference without parallel sessions and the organisers were more imaginative than usual in providing us with opportunities for interaction.  At the end of first day of talks, we went on a guided walking tour of old Toulouse.  At the end of second day, we went to the Toulouse Aerospace Museum and had the chance to go onboard Concorde.

I stayed an extra day for an organised tour of the Airbus A380 assembly line.  Only the engine pylons are made in Toulouse.  The rest of the 575-seater plane is manufactured around Europe and arrives in monthly road convoys after travelling by sea to local ports.  The cockpit, centre, tail sections of the double-deck fuselage travel separately on specially-made trucks with each 45m long wing section following on its own transporter.  It takes about a month to assemble these massive sections.  This is engineering on a huge scale performed with laser precision (laser systems are used to align the sections).  The engines are also manufactured elsewhere and transported to Toulouse to be hung on the wings.  The maximum diameter of the Rolls-Royce Trent 900 engines, being attached to the plane we saw, is approximately same as the fuselage diameter of an A320 airplane.

Once the A380 is assembled and its systems tested, then it is flown to another Airbus factory in Germany to be painted and for the cabin to be fitted out to the customer’s specification.  In total, 11 Airbus factories in France, Germany, Spain and the United Kingdom are involved in producing the A380; this does not include the extensive supply chain supporting these factories.  As I toured the assembly line and our guide assailed us with facts and figures about the scale of the operation, I was thinking about why the nuclear power industry across Europe could not collaborate on this scale to produce affordable, identical power stations.  Airbus originated from a political decision in the 1970s to create a globally-competitive European aerospace industry that led to a collaboration between national manufacturers which evolved into the Airbus company.  One vision for fusion energy is a globally dispersed manufacturing venture that would evolve from the consortium that is currently building the ITER experiment and planning the DEMO plant.  However, there does not appear to be any hint that the nuclear fission industry is likely to follow the example of the European aerospace industry to create a globally-competitive industry producing massive pieces of engineering within a strictly regulated environment.

There was no photography allowed at Airbus so today’s photograph is of Basilique Notre-Dame de la Daurade in Toulouse.

Designing for damage

Eighteen months ago I wrote about an insight on high-speed photography that Clive Siviour shared during his 2016 JSA Young Investigator Lecture [see my post entitled ‘Popping balloons‘ on June 15th, 2016].  Clive is interested in high-speed photography because he studies the properties of materials when they are subject to very high rates of deformation, in particular polymers used in mobile phones and cycle helmets – the design requirements for these two applications are very different.  The polymer used in the case of your mobile phone needs to protect the electronics inside your phone by absorbing the kinetic energy when you drop the phone on a tiled floor and it needs to be able to do this repeatedly because you are unlikely to replace the case after each accidental drop. A cyclist’s helmet also needs to protect what is inside it but it only needs to do this once because you will replace your helmet after an accident.  So, the kinetic energy resulting from an impact can be dissipated through the propagation of damage in the helmut; but in the phone case, it has to be absorbed temporarily as strain energy and then released, like in a spring.

Of course there is at least an order of magnitude difference in the consequences associated with the design of a phone case and a cycle helmet.  We can step up the consequences, at least another order of magnitude, by considering the impact performance of the polycarbonate used in the cockpit windows of airplanes.  These need to able absorb the energy associated with impacts by birds, runway debris and other objects, as well as withstanding the cycles of pressurisation associated with take-off, cruising at altitude and landing.  They can be replaced after an event but only once the plane as landed safely.  Consequently, an in-depth understanding of the material behaviour under these different loading conditions is needed to produce a successful design.  Of course, we also need a detailed knowledge of the loading conditions, which are influenced not just by the conditions and events during flight but also the way in which the window is attached to the rest of the airplane.  A large and diverse team is needed to ensure that all of this knowledge and understanding is effectively integrated in the design of the cockpit window.  The team is likely to include experts in materials, damage mechanics, structural integrity, aerodynamic loading as well as manufacturing and finance, since the window has to be made and fitted into the aircraft at an acceptable cost.  A similar team will be needed to design the mobile phone casing with the addition of product design and marketing expertise because it is a consumer product.  In other words, engineering is team activity and engineers must be able to function as team members and leaders.

I wrote this post shortly after Clive’s lecture but since then it is has languished in my drafts folder – in part because I thought it was too long and boring.  However, my editor encourages me to write about engineering more often and so, I have dusted it off and shortened it (slightly!).