Tag Archives: innovation

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!).

Image: https://commons.wikimedia.org/wiki/File:Airbus_A350_cockpit_windows_(14274972354).jpg

Formula Ocean

I have had intermittent interactions with motorsport during my engineering career, principally with Formula 1, Formula SAE and Formula Student teams.  The design, construction and competition involved in Formula Student generates tremendous enthusiasm amongst a section of the student community and enormously increases their employability.  As a Department Chair at Michigan State University, I was a proud and enthusiastic sponsor of the MSU Formula SAE team.  However, I find it increasingly difficult to support an activity that is associated with profligate expenditure of energy and resources – this is not the impression of engineering that should be portrayed to our current and future students.  Engineering is about so much more than making a vehicle go around a track as fast as possible.  See my posts on ‘Re-engineering Engineering‘ on August 30th, 2017, ‘Engineering is all about ingenuity‘ on September 14th, 2016 or ‘Life takes engineering‘ on April 22nd, 2015.

There are many other challenges that could taken up by student teams, in competition if that encourages participation, which would benefit human-kind and the planet.  A current hot topic in the UK media is the pollution of oceans by waste plastic [see for example BBC report]; so, engineering undergraduates could be challenged to design, construct and operate an autonomous marine vehicle that collects and processes plastic waste.  It could be powered from the embedded energy in the waste plastic collected in the ocean.  It would need to navigate to avoid collisions with other vessels, coastal features and wildlife, and to locate and identify the waste.  These represent technological changes in chemical, control, electronic, materials and mechanical engineering – and probably some other fields as well.  I have shared this concept with colleagues in Liverpool and there is some enthusiasm for it; maybe some competition from other universities is all that’s needed to get Formula Ocean started.  The machine with the largest positive net impact on the environment wins!