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by Andrew H. Dent, PhD
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Performance in automotive vehicles used to mean just one thing: speed. Top speed, speed of acceleration, cornering speed, stopping speed. Nothing else mattered. Every new car sold in the west today can comfortably do 40 mph over the maximum national speed limits for almost every country (save of course Germany and some rural areas of the US). But as anyone who has driven in the last 15 years in any metropolitan area knows, no one is really concerned that their car’s maximum speed can reach 140mph. Take the same poll in the developing world, and you would find that to go faster than 45 mph in many areas would be a cause of danger. This is simply because the roads are not suitably metalled, or there is significant congestion, just as in the west, or that the culture is such that the road is not exclusively the province of cars, with motorcycles, bicycles, pedestrians and livestock all wanting equal access.
If you want to produce a car for the majority of the world’s population today, using the standard western model will mean that it is way overengineered.
Given this new paradigm in motoring, why should I need to pay for a car that has an adaptive cruise control system designed for the Autobahn if I never get past 50 mph on the odometer? All the engineering that has gone into enabling speed (and of course safety at speed) isn’t really needed for much of today’s driving. If you want to produce a car for the majority of the world’s population today, using the standard western model will mean that it is way overengineered.
 So, after the looks of disbelief about the commercial launch of the Tata Nano in mid 2009 with a $2,500 price tag, the rest of the world’s automakers set about trying to come up with their own versions. Thing is, this is hard if you use the traditional method of producing lower-end cars – which is to remove features and use cheaper materials – as it will only get you so far. The low-end version of your marque can still travel comfortably at 120 mph (albeit at very high engine noise), and has all the engineering to ensure that everything else can survive at this speed too. What Tata did was to build a covered, four-wheel, four seat motorbike, which allowed for lower costs for just about all of their engineering parts. Airbags, turbochargers, automatic transmissions built for a small, relatively ‘slow’ car are smaller, and cheaper. Sounds simple, but none of the other big car companies had even considered it, and are now rushing to come out with equivalents to catch up.
Performance is not about maximizing (or minimizing) things, but about designing for need.
You see, performance is not about maximizing (or minimizing) things, but about designing for need. Overengineering is not a bad thing when it comes to safety, but for most other aspects, is unnecessary, and is in fact poor design. Materials use is critical to this issue, because the correct use of material for a given design should be centered on performance. Whether it is sustainability, impact resistance, light transmission, stiffness or slip resistance, there is a material that offers the optimum performance.
 To avoid overengineering, the prediction of the optimum material for a specific property can be achieved through the use of material selectors, such as Granta Design’s Cambridge Engineering Selector (CES), developed by Professor Mike Ashby and colleagues (www.grantadesign.com). Created through exhaustive research into the properties of a very wide range of basic metals, ceramics, polymers and composites, it allows for a quick and easy comparison between, say, nylon, ABS, plain carbon steel and an aluminum alloy, in terms of stiffness, maximum temperature use and resistance to impact. Alternatively, given a specific set of parameters such as tensile strength, stiffness, weight and environment, what is the optimum material (or materials) that can be used?
Designing to exact performance where it matters, yet enabling creativity and innovation is what new materials offer. Do it right, and what you create should also be a sustainable product. Do it wrong, and you end up trying to sell a Tata Nano alternative for double the price.
 This type of sensible material selection is heaven for an engineer (thinking inside the box is how engineering works), but feels like constraints for any type of real creativity. This is where innovation (and the value of sources like Material ConneXion) comes into play, because it is only through new structures, alloys, materials and processes that we can satisfy the performance requirements yet offer additional functionality or aesthetics. Innovations such as optically clear silicone (MC# 6618-01); stiffer, glossier polypropylene without the need for glass fiber (MC# 6469-03); honeycomb structures directly formed from flat plastic films (MC# 6643-01); and high pressure laminates that use sugar instead of formaldehyde as the resin (MC# 5359-08), enable greater creativity while still ensuring that performance is maintained, thus keeping the engineers happy.
Designing to exact performance where it matters, yet enabling creativity and innovation is what new materials offer. Do it right, and what you create should also be a sustainable product. Do it wrong, and you end up trying to sell a Tata Nano alternative for double the price. M |
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