composite stress analysis ?

[rb1957]

I'm wondering how FEA of a composite shell, with different laminae build-ups, understands which plies are continuous. like ...

1) when you add core the continuous plies are on the surface ... something like 1/2/3/4 becomes 1/2/5/3/4 (where 5 is the core). And yes I know the ply properties ... in the laminate build-up card you spoecify plies in order so ply 1 is prop 1, ply 2 PID 2, ply 3 PID 2, ply 4 PID 1 and then ply 1 PID1, ply 2 PID2, ply 3 PID3 (core), ply 4 PID 2(continuous from ply 3), ply 5 PID1 (was ply 4).

2) when you add plies, so 1/2/3/4 becomes 1/2/3/4/5/6 or 1/2/new/new/3/4 ... yes?

My thought is that using centroid results is enough to say "all plies fully effective" but that sounds (like me I suppose) simplistic.

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[SWComposites]

rb - there is no FEA code that I am aware of that knows certain plies are continuous between elements. The codes only form the stiffness matrices for each element separately. Then the individual element stiffness matrices are combined but the ply discretation is lost at that point.

 

[rb1957]

that's what I thought. elements are considered to be fully effective, which might work for large elements with centroidal stresses relatively far from the edges

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.