Meet the relatives

The Cambridge Engineering Selector from Granta Design allows design engineers to relate material properties to their clients’ requirements in a systematic and quantifiable manner.

The Cambridge Engineering Selector (CES) from Granta Design allows design engineers to relate material properties to their clients’ requirements in a systematic and quantifiable manner.

Developed over the last fifteen years by Professor Mike Ashby and colleagues at Cambridge University and Granta Design, CES has now been enhanced to allow engineers and the polymer producer industry to share in its benefits.

Granta Design was founded in 1994 as a spin-off from Cambridge University and aims to tap into the potential of materials information, by providing decision support software, reference databases, and customisation services.

The company has over 400 customers worldwide, including diverse industry sectors such as Dow Chemical, Benetton Formula 1, Applied Materials, Matsushita Electric, Lockheed Martin, NASA, and universities including Cambridge, MIT, and UCLA.

According to Andy Fenn, Granta Design’s Polymer Product Manager, CES is unique in letting polymer developers see how materials fit into the competitive landscape.

‘Comparing materials for any application is complicated because there are so many different properties that are important. Ashby’s methods allow you to quantify how new materials perform against their competitors and literally see the trade-offs that end-users will be considering,’ says Fenn.

‘We can identify desirable property profiles for new materials research in a market-driven fashion. We can visualise the effect of fillers and additives in a whole new way.’

Ludo Aerts of Dow Benelux, an experienced CES user, says, ‘We use the graphical capability of CES and the Performance Index methodology to prove, in a quantifiable fashion, the benefits of polymers over traditional material choices.’

CES is said to feature a comprehensive database of all classes of materials and their properties allowing comparison not just between different plastics, but also with metals, ceramics, foams, elastomers, and natural materials. Where required, Granta Design works with customers to customise the database to meet specific requirements.

The power of CES is derived from its graphical capability and the key concepts of performance indices and property space.

Derived from mathematical analysis, a performance index is the combination of material properties that best characterise the performance of a material in a particular application. They are believed to be a powerful means of effecting optimal materials selection. For example, in many applications designing on specific stiffness alone is simply not enough. Materials property space is a complex multidimensional environment in which every material has its own ‘hyper-volume’ which is determined by its combination of properties. Particular regions within property space correspond to optimal property profiles for particular applications.

Hence materials that lie in a given region represent an ideal material choice for that application. Holes in property space exist where no materials currently exist and material development opportunities can be readily identified.

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