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FAA report AFS-120-73-2, which developed a procedure for calculating lives for GA aircraft, has a decent discussion on scatter factor (if you can find it). I'm attaching an excerpt of the relevant pages (last part of pg. 7 and 1st part of pg...

Cold working a hole by definition involves plastic deformation. Therefore whether or not an interference fit fastener cold works the hole depends on the amount of interference and whether the surrounding material is stressed into the plastic region. What is not in doubt is that fatigue life...

After 15 years in this industry, I've only ever worked at two aerospace companies where I was not told point blank to do something unethical (if not downright illegal). If you do not deal with this now you will likely have to deal with a similar situation at the next job. Work up the chain of...

I have a little background info. to offer on this... The NIAR (National Institute for Aviation Research) at Wichita State U. has been disassembling aged GA aircraft to develop a SSID for them, which hopefully, will reveal areas to look at on older GA aircraft in general in order to prevent...

I'm using 8.3. You can assign mesh size criteria using the options under mesh-mesh control. You can assign a mesh spacing that varies along the length of a curve, or along the edges of a surface for example. This lets you vary the mesh size as you move along geometry. How do you like 9.0?

I'm not familiar with the report, but I am familiar with Moineau. His idea for an aircraft supercharger didn't work too well, but it worked great as a heavy-duty pump. It is marketed today as a progressing (or progressive) cavity pump by companies like Robbins and Myers. Their trade name is...

I use NASTRAN for windows, which is a version of FEMAP, and have had the same problems with CBUSH elements. When I ran the analysis, it got confused about the properties I had set up and wrote viscous fluid elements in place of some of the CBUSHes. The workaround they gave me was to...

rb1957, you make a good point. I work at a company just starting to use real blades as opposed to whip and semi-conformal antennae. They have NO criteria set up. I am pushing to formalize some. I have done extensive work on blades in the past, both from the aero side and the structures side...

catiadesigner: I know of no double-countersunk insert. You might try machining a countersink into the opposite side of a countersunk NAS1834. Also, you might look at some of the two piece inserts that are available from companies like TYE (the young engineers). I think they can mix and match...

Thanks, guys. I'll try to check those sources out. In the meantime, keep 'em coming. Thanks again!

Regarding the fatigue life of dimpled riveted joints, I know I have seen information somewhere long, long ago (in a state far away), that said it was worse than machine countersinking, but I can't find it or remember what I saw it in. I'm thinking old Douglas SRM's??? Anyway, we dimple every...

HI, shepflylow. What you need to do is to select modify...color...element. When the dialog box to select the elements comes up, pick the "methods" button and select "by material" option. Then you have to enter the material ID number that you want to change the color of, and you can then...

Mike and Artisi are right regarding the curve. I have designed progressing cavity pumps, and am familiar with the confusion that can result from the curves. The problem is that this is a positive displacement type pump, and the curves are different from centrifugal pump curves. With a...

Like jxc, I have encountered fatal errors where a degenerate element was detected by the solver. You can't get any results that way (normally, anyway. You can force Nastran to solve). The hard part is finding and deleting these bad elements with some pre/post processors! Sometimes you can't...

Gotta chime in here - I'm in structures, but the same idea will apply... Get practical experience via a co-op or internship!!! Typically, even though you are graduating with a master's degree, companies still have to do a lot of training to bring you up to speed after graduation. Having some...

We use it for just this purpose. It is like the opposite of nastran. Nastran gives you incredible control over details and tools for building models from geometry, but setting up for runs and pulling results can be tedious. In stresscheck, if what you need to model isn't in the handbook, you...