The CES software

from teaching to design, discovering a new field in materials science

Yves Brechet, Institut National Polytechnique de Grenoble, Advanced Engineering Materials, February 2003

Efficient materials and process selection is a key issue in mechanical design. Over the last ten years, Granta Design has issued a number of software packages aiming first at materials selection, then at process selection, then at combined materials and process selection. Over the years, the databases became larger, the conceptual tools developed by Professor Ashby and his collaborators became more and more sophisticated, and one can say that a new field in materials science—"rational selection"—has emerged from this booming activity. The underlying philosophy—objective comparison and hierarchical approach to databases—has proven to be very useful for stimulating innovative design. The latest packaged issued by Granta Design, CES4 (now updated in CES EduPack), is the fruit of this evolution. The best way to present CES is perhaps to look behind into the history of its development.

The very first software packages, the CMS series, were a gem of paedagogy, but the restricted amount of information contained in the databases limited their application mainly to teaching. The key ideas were present, and rich enough to stimulate, as far as the methodology was concerned, a wealth of research activities in close relation with industry. But the enormous amount of information required for an efficient application to industrial problems was still to be gathered. However, it was a beginning and a "tour de force "—one that only Mike Ashby, with his wide knowledge of all materials classes, could have initiated. Had he not tried it, nobody would have dared to do it!

Of course, there were immediately some complaints about the simplicity of the approach, but also a growing interest in its potential, and in the need to develop in parallel conceptual methods and comprehensive and structured databases. Ten years of research and development, ten years of testing the ideas on both academic and industrial situations followed this first breakthrough of materials science into the complex field of design 

Since this pioneering work was issued, the databases have expanded enormously, in metals, polymers, ceramics, foams, steels, conducting materials, magnetic materials, natural materials . There are now, beside the generic database, 10 specific ones, the full package lists about 3700 materials with a wide range of properties. The databases on process attributes were a step forward towards a real design tool (forming processes, joining processes, surface treatments ). The current status list 220 processes with their attributes, technical as well as economical.

[Note, the range of materials, processes, and properties in CES EduPack databases has grown since this article was written, and continues to grow].

Soon it became apparent that temperature dependant data would be required, so the possibility of storing curves and not simply numbers was offered. The information available is not always structured, so Granta provided various text searching tools for a number of classic handbooks via the Web. Industries complained that the data they are interested are very specific, so the possibility of building one's own database was offered.

Over these years, the successive CES software packages became more and more efficient, contained more and more information, and appeared more and more flexible.

However, the initial simplicity of the CMS series was somewhat lost in the amazing gathering of data that Granta had managed. The new CES4 is another astonishing "tour de force": it has all the potential of the latest generation of CES software package, and it has recovered the classic elegance in pedagogy that was the signature of the very first CMS software developed by Mike Ashby. The new CES is now in full maturity: the databases are as rich as ever, but structured into "introductory" and "advanced level". Each material and process in the database has a record on properties, but also some visual examples of its applications. The full power of "CES Constructor" is made available at the advanced level. The databases now evolve toward functional materials and not only structural ones.

But the software is not the whole story: the EduPack contains also lecture notes, PowerPoint presentations, projects, exercises, all the material that is required to start a course in this field at the best level. Having taught materials and process selection in the last 10 years, teaching students projects directly provided by industry, I can witness both that final year students can, with the help of this methodology, propose solutions worthy of interest to industry, and also that they take an active part in the teaching. Seeing 1st year students coming to your office to ask to be taught in materials selection because last year's student told them how much they were excited by their project is a reward than no educator can underevalue!

The CES software is a masterpiece which can now be used not only for educational purposes, but also directly brings the researcher and the engineer up to the current level of expertise in the field. A lot of work is still required in this field of research: storing expertise, learning from failure analysis, finding applications for a new material or a new process. Many new domains can be addressed: mechanical design, micromechanics, selection of products, MEMS devices. The research area opened by Mike Ashby ten years ago is wide and many disciplines can contribute to it. It is not so often in materials science than a research field develops so rapidly, so closely related to industrial concerns, and so immediately transferable to students. With the present tool which has all the features of maturity, one can hope that the difficult but crucial problem of design will have its way through the materials science curriculum, that knowledge of materials will become a must for other engineers. It will set new standards in teaching engineers in materials science, with an active paedagogy on real-life problems. Last but not least, it will bring to the knowledge of the academic community this exciting cross-disciplinary new field of research activity , and hopefully will attract new active contributors.