Predictive Engineering tapped Autodesk Simulation to conduct FEA and CFD analysis to simulate air flows on a firefighter respirator mask project, as part of an effort mandated by the National Institute of Science and Technology (NIST).
Image courtesy of Predictive Engineering Inc.
I've always found FEA and CFD to be fascinating, and use to write about them in the old days when I was at Mechanical Engineering magazine. At that time, one of the impediments to doing serious analysis on PCs was the availability (or lack thereof) of processing power. Today, cycles are free, so it makes sense to incorporate FEA and CFD analysis capabilities within core CAD products. The aspect which still requires work, as you mention in this piece, is user training, because there are deep experts among users and there are newbies. I suspect though that what the broadened availability of FEA and CFD does is to allow casual users to run occasional analyses. The people dedicated to this as their core discipline having highly tuned setups and do this on an ongoing basis in any case.
You pegged it, Alex. The idea is that tightly-integrated FEA/CFD capabilities as part of CAD platform allow design engineers to do casual analysis throughout all stages of development as opposed to coming up with a design, throwing it over the proverbial wall to the CAE specialists for simulation, and then trying to incorporate those findings back into the design.
What happens with this traditional, siloed approach is that simulation is performed a couple of times in the process and typically too late when it is far too costly and complex to make changes. With the tools easily accessible, from the CAD platform or in the cloud, a design engineer can iterate and optimize their design continually throughout the process and hand off the end result to the specialists to do the final optimization. That way, more designs are tested and optimized, enabling teams to hone in on the best option and resulting in far more innovative and cost-effective products. At least that's the goal.
Thirty years ago, many great engineers with a lifetime of experience were intimidated by FEA, and therefore steered clear of it. One of the great advancements of the last decade is that the "newbies" are able to draw a wealth of important information from this technology without needing a background in structural mechanics.
Chuck, I think that's really important perspective and really gets to the core of why these advances are so key to advancing the engineering process. If less experienced engineers can readily gain access to FEA and CFD without being dependent on a tight coterie of specialists and without feeling intimidated, they're more likely to leverage simulation as a regular part of their design workflow. Doing simulation continuously throughout the process will then (or should) ultimately lead to better optimized products.
I did quite a bit of FEA work 10 years back. It was really very easy to run. Recently I investigated CFD and was suprised to see its still a very difficult program to run. Maybe I need to look at competing CFD programs to see if there are any that are more user friendly.
Is it the case the CFD still tends to be more specialized than FEA? That is, I always think of CFD in terms or aerodynamics analysis (whether for automotive or aerospace), and also those program runs I've seen where they analyze how liquid shoots into bottles (like when you're filling beer bottles in a production line). FEA seems on its face to have broader application, because most every product design can benefit from a stress analysis.
FEA capabiliteis are definitely more common and more likely to be integrated with the core CAD platform. While we're starting to see more CFD integration, it definitely seems to be more specialized and tuned for specific industries while the need for FEA appears to be more universal.
You missed one. The COMSOL Multiphysics LiveLink modules also allow users to run Multiphysics simulations within their preferred software of choice. We currently have plugins for Solidworks, Pro/Engineer, Inventor, Spaceclaim, Creo Parametric, and Autocad. http://www.comsol.com/products/multiphysics/
My apologies for the oversight. Thanks for putting COMSOL LiveLink on our radar screen. It's exactly that kind of integration with leading CAD tools that is helping put CAE applications in more engineering toolboxes.
Great slide show, Beth. you mentioned these tools enable more collaboration. Do you know if that is actually happening? This sure seems to support collaboration. but then collaboration is often a political matter. Even so, tools such as these could cut through company politics.
Rob, I wouldn't necessarily classify these advancements as collaborative, although there is always some sort of back and forth between design engineers and the simulation specialists. What many of these new capabilities do is allow the engineer to do their own simulation work intermittently throughout the design process so there isn't this huge disconnect between the day-to-day design iterations and the on-going optimization around simulation. I guess it's a form of collaboration, to some degree.
Simulation software, including FEA, CFD, and solidification codes, among others, can be a tremendous resource. For example, if you are designing a cast piston for an engine, you can simulate everything from how the mold will fill and how the metal will solidify, to the stresses and strains the part will experience in service and how the dome shape will interact with the spray pattern. This allows you to refine the part for both manufacturability and performance long before it is even made.
That being said, in order to make good use of these tools, it's absolutely essential to have a solid engineering understanding of the physical situation. The increased user friendliness of software is a double edged sword. It's easy enough to set up a simulation and get numbers out - but knowing how to set the simulation up to accurately reflect the parameters of the physical situation, how to interpret and use the results, and how to tell whether the results make sense, are another matter.
One mistake I've often seen from engineers (who should know better!) is to use FEA to find the maximum stress in a part, and then compare this maximum stress to the "fatigue strength" of the material. Among other things, these engineers must have been sleeping in class when their professors were talking about the Goodman diagram. (Actually, the Goodman diagram itself is a highly inaccurate way of taking mean stress effects into account, as this paper shows).
Of course, there are fatigue codes like feSafe which apply very sophisticated approaches to fatigue. But even still, there is no substitute for physical insight into the problem.
Dave: You aptly point out one of the dangers of making simulation tools more accessible to mainstream folks. If you don't know the physics of what you're trying to simulate or set up the simulation model correctly, there is opportunity for making assumptions that lead you down a problematic design path.
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