Better tools for conceptual design

Is sustainability something software can help designers achieve? Justin Cunningham finds out.

Balancing environmental impact with economic considerations is a difficult and constantly shifting trade-off. Sustainability is becoming an increasing driver and constraint for many designers and engineers. More and more legislation, regulation and compliance pressures affect which materials can be used, energy efficiency ratings, and disposal considerations.

To help design engineers, most of the software companies are adding functions in one form or another to help companies with their 'sustainable strategies'. Although the current buzzword of sustainability is being thrown around, it is at present more about compliance and minimising environmental impact in terms of CO2, material usage, energy efficiency, and making products safe and easily disposable. For most, true sustainability is more of a design ideal than a practical option.

Eduard Marfa, EMEA marketing director at Siemens PLM, says: "About 60 to 70% of your product's environmental impact comes from decisions made in the planning stages. So if you choose the right materials and right supply chains at that time then you will end up building better products that are more environmentally friendly."

To date, much of the effort by design engineers has been in minimising the amount of material in a design, without sacrificing the mechanical properties a component might need. This has predominantly been done through finite element analysis (FEA), which has allowed different materials and geometry to be assessed for a level of optimisation. Other simulation tools can help to assess friction, optimise bearings, and other moving and mechanical parts.

Siemens PLM, like many similar systems, has a lot of tools to help audit parts and the bill of materials (BOM) to make sure products don't contain prohibited substances and, if they do, make sure they can be tracked as this impacts manufacture and disposal.
Increasingly, standards such as RoHS, mean companies must track not just four or five dangerous substances, but over 3000 different materials. One shift that has been seen and given a lot of help from CAD companies has been the use of all these design tools right at the front end, as part of the conceptual design phase. Autodesk vice president of suites and web services, Andrew Anagnost, says: "These things have always existed but have become much more important. They are being used much earlier in the design process as disposal and energy standards have become more and more rigid. Material selection is also very important. There are all sorts of things in terms of compliance and life cycle considerations when selecting materials."

Autodesk has recently announced that it is to include an 'Eco Materials Adviser' in its 2012 version of Autodesk Inventor. This will allow designers to quickly view information about not just the mechanical, thermal and optical properties of a material, but also detailed information on its environmental properties. It can be used on both individual parts and full assemblies and is accessed on an easy-to-read dashboard display that shows key indicators such as energy usage, restricted substances, CO2 footprint, water usage, and materials cost.

The software has been developed in partnership with Granta Design, which was spun out of Cambridge University in 1994. Its material database – called the Materials Universe includes data on ceramics and glasses, fibres, composites, foams, natural materials, all classes of metals and alloys, all plastics and elastomers and is continually updated and by a team of material and lifecycle assessment professionals developing and improving it.

Dr Jamie O'Hare, eco design product manager at Granta Design, says: "The unique thing about this database is that for all the 3000+ materials in this database there are a complete set of engineering attributes including Young's Modulus, tensile strength, yield strength, thermal properties, and optical properties.But now we have added environmental properties, so embodied energy to produce a kilogramme of a material, CO2 footprint to produce a material."

The result is the ability for engineers to specify all the important constraints in a design specification both in terms of physical properties as well as environmental constraints. You can search for materials for which are food-contact compatible and RoHS compliant, the amount of recycled material routinely included in 'virgin' material t or CO2 emissions per kg of material produced.

"So if you search for materials with a recycled content of over, say 5%, you know that it is technically feasible to recycle, and also the infrastructure must be in place to actually do the recycling," says Dr O'Hare. "We think this is more valuable than a simple tickbox which says 'recyclable' because there are many materials that can be recycled but it is not economically feasible or practical to do so."

The environmental data provided is pretty accurate, but is generic, and will also be quoted as a range alongside a percentage that represents the degree of inherent uncertainty of the data. It does not, for example, go to the plant or country level where a raw material might originate but will give an average account of what, typically, a given material has in terms of environmental impact properties.

"That is still good enough because of where it is being used in the design process," argues Dr O'Hare. "The difference between materials made in China or Europe is relatively small. But the difference between a steel and aluminium may be orders of magnitude. Therefore, in the early stages when you are assessing entirely different concepts, differences of ±20% should not be considered significant as there is a degree of inherent uncertainly in environmental data anyway, you simply can't provide that level of detail in environmental data. But it is possible to make good design decision even with that uncertainly."

Once a designer has assigned materials and processes, an initial assessment can be run via the dashboard in Inventor. Once the baseline calculation is set, the materials can be changed and the difference can be assessed. The base version is being shipped as an integrated part of Autodesk Inventor 2012 with the full version available as a paid for upgrade.

Last year, Granta Design also teamed up with PTC to develop its MI:Materials Gateway for Pro Engineer. The software aims to manage a firm's material information such as results and analysis from material tests, research, and previous project experience. Again, it is hoped this can then be used for better early design assessments; economic and environmental data on materials; and information on the restricted substance status of materials.

These tools are helpful first of all as a means of enlightening engineers about new possibilities in terms of the structure or material of a given design brief. In addition, they are increasingly giving engineers an insight in to Life Cycle Assessment of conceptual designs which should act as a guide to inform them, at the early stages, how to make 'sustainable' decisions.

Justin Cunningham

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