Re: [PipingDesign] Fwd: Steam Stress Analysis

On Mar 24, 2008, at 8:31 AM, Kevin Green wrote:

> Nice way to correct me!

Not at all. I was trying to show that you're waving a sword that cuts both ways. I wasn't correcting--I was waving the same sword and cutting the other way. I've been making a pretty good living with FEA for about 30 years--probably longer than most people on this list have known the diffference between pipe and poop. ANSYS or Caesar or what-have-you is fast and can even be productive, but my experience is that sound judgment can remedy weak analysis, even weak FEA, but I've never seen good analysis make up for weak judgment.

> Yes and many a times these great things have been overdesigned and
> were designed and constructed in those times when nobody gave a
> damn to schedule and project cost.

I don't think the projects I mentioned were any of those--maybe the Taj Mahal or the Hagia Sophia could have been built cheaper or to a tighter schedule, but to what purpose? Compared to the real value of anything I mentioned--take the DC-3, for example--the money and time saved by doing the whole stress analysis with ANSYS would have been trivial. Unfortunately for my ego, the same is true for most worthwhile projects. Not that it wouldn't be a big rush to go back over the Golden Gate bridge piece by piece, but it's hard to imagine anything would be saved. OTOH, I've seen a hundred FEA 'experts' who'd probably have advised adding another wing to the Spitfire after a month of running random response on the airframe.

Christopher Wright P.E. |"They couldn't hit an elephant at chrisw@skypoint.com | this distance" (last words of Gen.

.......................................| John Sedgwick, Spotsylvania