The Simulation World: the designer and the analyst

If you have read more than a sentence of any of my posts, you know that I am a fan of simulation, FEA or CFD or other, to be done throughout the product life cycle. I think the earlier in the design process the better. Anyone that has done very early, proof of concept models can verify that if done properly the payback can be invaluable. In many organizations, the person responsible for this sort of simulation varies.

Some of the smaller/newer organizations tend to have multi-tasking engineers that are responsible for the entire gamut of tasks - design, testing, material selection, manufacturing, support and simulation. The larger and older organizations tend to be a bit more hierarchical and lines are a bit more defined.

My goal is to not pick sides here, although I definitely do tend to lean toward one side. I just wanted to point out some observations. I sat through some really cool presentations last week at PLM World, in particular the NX NASTRAN presentations. There were some really insightful conversations and ideas being presented. I was a bit surprised at the demographic of those presenting. The room was filled by veteran engineers, clearly with mountains of FEA experience and were passionate to bring the NX flavor of NASTRAN up to snuff.

Could be simply the group of folks that attend this sort of thing, but I was a bit surprised that there were not young, enthusiastic engineers in there pushing a new breed of ideas in with a passion. I know that the seasoned guys know there stuff, but I firmly believe that the new crew of engineers can and will drive the software companies to develop products of the future. So I began to accept this idea that the analyst demographic, for now, are the veterans in the audience.

On the opposite side of the spectrum, I cruised down to the Solid Edge Simulation hands on session. I figured, this is where I will find the new breed banging away. There certainly were some, but it was clear that it was pushing comfort zones to the max.

My findings at this event are seen at every conference and in numerous companies all over the world. I love what the Siemens' folks are doing to position themselves as a leader in the simulation world. I hope that young engineers continue to push themselves to incorporate simulation as part of the design process.

I think that many young engineers are entering the work force with a fair amount of knowledge about simulation. It is now up to the engineering managers out there to open their minds, expand the comfort zone and allow the new breed to help implement the tools that are available.

The Cost of Wind Tunnel Testing vs. Upfront CFD

I have written many times that I am a huge fan of Desktop Engineering Magazine. There was an interesting article recently on Conceptual Design. It is my favorite type of article. They poll four different representatives from four different vendors (Rhino, SolidWorks, Siemens & Autodesk) and ask a variety of questions to see how each tool responds to demands of the market.

The article was near and dear to my heart. Conceptual design is something I live and breath everyday. Each rep from the various vendors had some really cool and unique views of where their products add value in the conceptual phase of design. I came across the following quote and almost fell out of my chair.

“For example,” he says, “wind tunnel or tank testing often is not all that expensive [when] compared to setting up and running CFD analysis. It is often easier to make the design iterations by playing around with a handful of clay and turn the wind tunnel back on, than it is to change the computer model and rerun the CFD analysis. But structural analysis of a large building design has to be done virtually. Physical analysis is economically impossible.”

It is interesting how many people share the same sentiment. The fact is there are only few instances where this may be the case. I was talking to an engineer at a very well-known valve manufacturer about this and he shared a few numbers with me.

He was designing a brand new line of poppet valves. He was responsible to ensure the pressure drop was within a certain range, as well as determining the spring needed to maintain stable flow over a wide range of flow rates. His ultimate goal was to have three prototypes (3 different sizes) ready to be outsourced for final physical testing. I asked how much were the outsourcing costs? $8k for three...whoa! Seemed steep to me, but I am all about virtual reality, I suppose.

So, let's say you didn't perform an Upfront simulation of the model and your three original designs were not up to snuff. So, you had to re-do the prototype testing. You have just justified the $$ for an Upfront CFD tool. But this is really just the tip of the iceberg. In reality if you had the simulation tool in place you could confidently pay for one round of validation testing at the end of the design cycle. But, more importantly, the simulation models would allow for innovative design that is not possible in the physical testing world. You aren't able to get in there and peel things away to see inside where the action is happening in a wind tunnel. You are limited on the data available and you induce inaccuracies with the measuring devices.

So, back to the article at hand. I think I understand where the guy was coming from. In the past, CFD was the big gorilla in the room. Everyone was afraid to go near it. It was too "expensive". Things have changed drastically over the years. More and more everyday. Whether its a wind tunnel, a flow bench or a thermal chamber or even a thermal camera, there are significant investments of time and materials required.

My friendly advice is to fire up Google and do a search for Upfront CFD.