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Femap with Nei Nastran rivet forces

Femap with Nei Nastran rivet forces

Femap with Nei Nastran rivet forces

(OP)
Hi all.

Can you aerospace types (or others) remind me how you typically extract shear flows for sizing skin to frame member connections? I have not modeled discrete fasteners, but just used glued contact in my FEA. What is the usual method with "older" FE approaches, i.e. merged shell elements, etc?

tg

RE: Femap with Nei Nastran rivet forces

I'd work off element shears

another day in paradise, or is paradise one day closer ?

RE: Femap with Nei Nastran rivet forces

(OP)
rb:

I have done the same many times - however, do you take the total shear over all the elements in a line and divide by total length (giving average shear flow) or is there another approach?

tg

RE: Femap with Nei Nastran rivet forces

you need to be careful using shears ... are they all aligned the same ? is it a straight forward connection (like the change in endload of strgr) or (more likely) a situation where shears are moving between several different members ?

but summing different element contributions is reasonable for ultimate static design, or you might consider the peak load applied to a representative number of fasteners.

another day in paradise, or is paradise one day closer ?

RE: Femap with Nei Nastran rivet forces

(OP)
rb,

Is there a standard or guide that helps define "representative number of fasteners"?

tg

RE: Femap with Nei Nastran rivet forces

any sizeable point load would be introduced via a fitting.

if you've got a lot of skin panel shear, and are splicing the skin panel, how many rivets would fit within the element ?

you could average over like a frame pitch.

if there's one shear spike, does it look reasonable to smear over three rivets ?

another day in paradise, or is paradise one day closer ?

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