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 don’t know what you’re 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 don’t 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. They may not even understand they are using FEA or CFD!
FEA and CFD are great tools if used with a clear purpose, by a qualified analyst and in a limited context. Physical testing expands the limits by adding reality checks that are always needed. However incorporating FEA into the design process can dramatically reduce the development time and costs. But it’s 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.
Here are some clear phases that are required in any product development, but note that product design and development is an iterative 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!
About the Author
Sara Leadbetter is a Business Advisor based in Christchurch, New Zealand. This article was written with Greg Morehouse, an expert in CAD, FEA and PLM softwares, and director of Motovated Design and Analysis Ltd. Motovated’s core business is helping small to medium manufacturers with most, if not all, of these steps. If you’d like to discuss any of these phases, please don’t hesitate to contact Greg at: http://www.motovated.co.nz .
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