Element Selection

[speed320]

Hi all,
I'm a basic user of FEA....using I-Deas ofr my stuff. I know element selection plays a big part in analyses. So are there any sources, online or in print, I can refer to for element selection? I've noticed massive differences in values when using shell or solid elements for the same structure, load and boundary condition sets.
Cheers

 

[zuardy]

Hi,
try to find it out from IDEAS text book, this would be better since the name of the elments is exactly then if you refer to a general FEM book.
Shell element is implemented on a structure, where the thichknes very small compare to the long or wide dimension (plane form), like a plate or fuselage of an aircraft. But you mast be care with the apllied loads, since shell element does not allowed rotation about the plane axis.

cheers

 

[Spirit]

Hi speed320, according to my experience it is very instructive to consider a simple structure, best if correlated to experimental results, and building a model using different element types/mesh refinements submitting it to the Analysis Task. You can so have an idea of the level of reliability you can expect vs. mesh size/element type. Any other suggestion I believe could be misleading, since the choice depends heavily on the type of problem you are considering: a consideration trivial, but too often neglected.
Cheers,

Spirit

 

[jstegmann]

Hi,

In my experience the use of shell elements require a good deal of insight since a number of things might go wrong. On the other hand it can often be difficult to obtain usefull results when modelling shell/plate structures with solid elements (e.g. 8- or 10 node). Simply because a large amount of elements is often required in order to render the model well-conditioned which is often computationally too expensive. If you have a shell-like structure go for the shell elements, but read your documentation well. Check for convergence by e.g. doing mesh refinement (h- or p-method) as suggested by Spirit.

Regards,

jstegmann.