I can flip the normal but can I then rotate the element's coord sys so that X points in a particular direction? Using Apex to pre-pre-process composite panels so element X direction is as important as element normal.
Element coordinate systems are governed by the element topology. For composites ply directions are referenced from the material coordinate system. See the image below.
As for the APEX... Which version of APEX are you running ? Composites modeling capability does not exist in the released versions of APEX. Although, my understanding is that it is being planned.
Right, so can I change that element topology in Apex? Looks like I can only flip the normal direction.
I wouldn't mind so much doing it in Patran but Apex is not exactly consistent with what it selects as the element orientation. If the surface is simple, it seems to select the same orientation for all elements. If the surface isn't simple, some portions of the surface have elements oriented one way and other portions have elements oriented differently.
No. Element x axis is fixed based on how the meshing is done. I.e. the locations of the nodes (1,2,3,4). That is why the concept of material coordinate system is introduced , with respect to which ply angles will be oriented and there is no need to change or rotate the element coordinate systems in patran either. One has to define the material coordinate system.
THETAi Orientation angle of the longitudinal direction of each ply with the material axis of the element. (If the material angle on the element connection entry is 0.0, the material axis and side 1-2 of the element coincide.) The plies are to be numbered serially starting with 1 at the bottom layer. The bottom layer is defined as the surface with the largest -Z value in the element coordinate system. (Real; Default = 0.0)
Sorry if I wasn't more clear. I'm pre-pre-processing models in Apex (mid-surfacing, glued interfaces, initial model checks) then shipping to Patran to add compsites info and more complicated loading than can be established with Apex. From Patran then to Nastran.
I had confused/combined element orientations and material orientations in my mind. Your response brought me back around. Thanks.
