2 questions: average value for element, average value for set of elements(selections)

cashancashan
As it is in topic.

I can easy check a VM stress for node, but - is it possible to check average stress value for element?

and

Is it possible to check average value for set of elements ( for selected elements or named selection) ?

Comments

  • disladisla
    Hi Cashan,

    All this is possible . Go to the SOLUTION menu ---> MEAN.
    You need to recalculate again in case you create a new element selection in order to see it
  • cashancashan
    Looks ok however ... not fit to me :).

    I am looking for VM stress described as: " σvm, is based on the membrane direct axial and shear stresses of the plate element evaluated at the element centroid. Where shell elements are used, the stresses are to be evaluated at the mid plane of the element. σvm, is to be calculate" (see.doc.: DNVGL-CG-0127 Sec.4 Ch.5 ).
    In other words - I would like to check a local membrane average stress at selected shell element. It is possible for result from internal solver (but not for CCX), however only for nodes. I need a average value for element. When i will build in each check a new component and recalculate it again and again it not effective (time consuming ).... Maybe it is a good idea to add this option (check average element stress at selected element) in new release?
  • VictorVictor
    I had a look at section 4.5.1/2/3 and it seems to really depend on the the element formulation being no better or worse than what they expect. Perhaps this is why only approved software is allowed? I was going to suggest refining the mesh to create a node at the midpoint but there are restrictions on that and even on obtaining the stress at the centroid by interpolation from the nodes as well as extrapolation which is how all the node stresses are generated by both solvers.

    A correct way may be to use stresses evaluated at integration points (see *EL PRINT) and choose the center integration point. Beware though that the center integration point is not necessarily at the geometric centroid for distorted elements.

    You can get CCX to average through the thickness. Copying my recent comment on that here:
    Not sure if this would help, but are you aware of OUTPUT=2D on *NODE FILE or *EL FILE? It causes shells remain as 2D elements in the solution and CCX averages the stresses from the 3D nodes into 2D, which loses information like bending stress but should be still useful for membrane stress.
    In Mecway 14, use CCX -> Modify Keyword -> *NODE FILE, Set parameter Name OUTPUT, Value 2D.
  • cashancashan
    edited December 2021
    It doesn't look promising. I can see that there is no easy way to display the average values for element / values in the middle of an element. Currently, the displayed values (in nodes) are relatively high. Averaged values for the elements give much lower results. Without the possibility to easily check such a value for an element, the results become useless for me [ in this case only of course ] :(.
Sign In or Register to comment.

Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

Sign In Register