Manufacturers! How Effectively Are You Using Cad Software To Test Designs?

Much has been written in the press in 2010 about the alleged design fault's on one of Toyota's new vehicles, and some blame has been incorrectly attributed to CAD (computer aided design) and PLM (product lifecycle management) software. However, it is likely that the issue is in the fundamental understanding of the function and operating environments, as well as the testing involved, not the actual use of CAD.

In general, both simulated testing via virtual analysis (including Finite Element Analysis, FEA and Computational Fluid Dynamics, CFD) and physical testing rely on a deep understanding of what can occur. Only once we understand what we are looking for can we address those issues specifically in the testing context. Limited (express) versions of both FEA and CFD have become freely available embedded within most CAD softwares, which is a danger for inexperienced users and may have contributed to this issue.

The challenge with any tool is it cuts both ways and the sharper the tool, the more damage that may be done when used incorrectly. If you dont know what youre looking for, any simulation is useless. If you don't have the experience or knowledge needed to correctly interpret the data, incorrect results are produced. Even worse, if you dont know the underlying limitations of the software, inappropriate extrapolations will be made, particularly with express versions of FEA software. In-built virtual simulation softwares allow designers to use a tool without paying the dues necessary to understand the technology. Unfortunately, due to the nature of the software, they may not even realize that they are using CFD or FEA!

FEA and CFD are great tools if used with a clear purpose, by a qualified analyst and in a limited context. Actual physical testing of a product ensures essential reality checks are made. However incorporating FEA into the design process can dramatically reduce the development time and costs. But its a total package of understanding the function of the device and its operating environment, combined with correct application of virtual simulation and physical testing, which provides the confidence to go to production.

There are clear steps to go through in any Product Development process. These phases have to be understood at a top level for coherency, but it is usually different people and different skill sets that produce the deliverables required:

1. Product Vision (including development plan and overall direction)
2. Virtual Modelling (conceptual development for marketing buy-off)
3. Design for Manufacture (including detailed modelling, calculations, drawing production and process development)
4. Virtual Testing (including tolerancing, interference checking, stress, buckling, resonant and dynamic analyses &/or flow analysis)
5. Physical Testing (including applied static loads, impact loads, fatigue loads and environmental testing etc.)
6. Production Development (How it's made, what, where and who)?)
7. Product Release (including customer feedback monitoring and warranty issues management)
8. Product Lifecycle Management (including on-going manufacturing and product development as well as product replacement strategy development)

Once in production, it is continuous product monitoring, awareness of warranty issues and quick response to known issues which will avoid product recalls. Because as we have seen, product recalls can cripple even the most robust of manufacturers!