Ah yes, the most complex problems are often solved with the simplest of solutions. Have you ever heard that somewhere before…bet you have! But do you practice it!? Perhaps not…no worries, because it now seems that solving engineering problems by leveraging the ubiquitous numerical titan known as FEA is the preferred problem-solving apparatus over all other methods…including the "simple" ones.
Let's go back to the "simple" days were old-school engineers engaged in a practice known as KISS! Now…Now…I'm not referring to anything risqué here…I'm "simply" referring to a time-honored practice known as "Keep It Simple, Stupid" …a design principal first coined by the NAVY in 1960.
For the technical savants out there, perhaps an apropos analogy is in order such as Occam's Razor or Leonardo da Vinci's "Simplicity is the ultimate sophistication"; or, the always popular variant (attributed by Albert Einstein), "Make everything as simple as possible, but not simpler". Now I would be remiss if I had failed to talk about simplicity without mentioning the legendary engineer Kelly Johnson from the famed Lockheed's Skunk Works. He referred often to KISS when deploying his "down-to-brass-tacks" management style (…now I like that!). Okay...well, I digressed there for a minute…I need to get back on point…you know keep it "simple".
"[KISS] is best exemplified by the story of Johnson handing a team of design engineers a handful of tools, with the challenge that the jet aircraft they were designing must be repairable by an average mechanic in the field under combat conditions with only [certain] tools. Hence, the "stupid" refers to the relationship between the way things break and the sophistication available to repair them."by Wikipedia
I too have witnessed the problematic aspects of relying entirely on FEA while remaining void of something as simple as a free body diagram. During a design review involving the evaluation of a stiffened, composite curved panel. The highly compensated team of stress analysts presented their margin summary along with an assorted array of impressive "Christmas Tree" plots showcasing the panel's strain distributions. After the presentation concluded and the venue opened up for Q&A…a perplexed Chief Engineer with a flummoxed look on his face quipped: "that was an impressive presentation, but can I see a "simple" Free Body Diagram?" Bemused by the question…one of the erudite analysts "simply" replied: "we don't have one of those." Funny…all the Chief Engineer wanted was a "simple" free body diagram. Was this another careless oversight…maybe? Doubtful though…today's businesses spend a lot of money on FEA software, so naturally, the business proclivity is to direct engineer's (regardless of their experience) to use these sophisticated numerical juggernauts for all analyses…regardless of whether the system is simple or complex. After all, dazzling senior management with complex visuals, that they themselves surreptitiously ponder in complete befuddlement, is preferred over the boring free body diagram…right!?
There are of course countless other examples…and that's the problem! That's just one example too many! With today's faster and cheaper engineering mantra…developing a simple understanding of the analysis first (such as load path) regardless of the complexity is an endangered phenomenon. The transition from intelligible design solutions that one can explain using simple models…to the more sophisticated...million-plus element FEM's is now the standard—not the exception. Now don't get me wrong, the power of numerical simulation, in the right hands, and when used correctly provides the added numerical capability needed to solve some of the more complex engineering systems. However, one must never lose sight of the need to simplify a complex system (whenever possible) down to a simpler one that reveals a designs strengths and weaknesses unambiguously. As one can imagine, the benefits of having an engineering system that is simple to understand for all involved are manifold…and all you really need to achieve this is a "Simple KISS".
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