¿What would be the correct way to define this BC.?
It is related to this interesting post by Lucas Bueno.
I can manage to improve the Buckling factor result up to 471.6 but there is no way I can completely remove certain out of plane rotation of the upper shell lip. (See Pict). That is most probably the last detail needed to achieve the exact analytical solution.
I was already constraining some additional nodes apart from strictly the ones on the lip but seems it gets better adding a second thin row of elements. (Good point from FEA). A third one seems to much.
HI Victor , How could I do that with *Boundary?.
I need to apply some loads and one Moment to the lip of an structure for further buckling analysis.
I don’t see other option to distribute those loads.
I’m finally using Fixed face on one side and Kinematic Coupling at the loaded side.
Kinematic side shows some disturbaces.
I’m familiar with those BC’s but how do I later apply the Moment?. I need a rigid body, kinematic or Distributed coupling which conflicts.
I could set up the torsion by means of a rotation imposed in the circumferential direction but imposed displacements doesn’t work for buckling.
you have to apply a traction in the loaded edge (y coordinate in NACA’s nomenclature) whose only resultant is a pure torsional moment. In the case of linear elements it’s a uniform distribution of tangential point loads at the nodes of a regular mesh (all elements would have same edge length). Unfortunately CCX doesn’t have this capability already implemented in *DLOAD so *CLOAD cards have to be generated.
right, these are the practical engineering methods, what I suggested is the numerical version of the mathematical condition so it can be better compared to the analytical analysis (Galerkin) used in NACA TN 1344
Documentation is not clear notified to avoid mixing, so probably it can be use or at least one keyword function is working. Previously i’m only curious about conflict you has been reported.
It"s not a conflict reports, but unexpected behaviour and maybe the limitation itself. It seems the model still need a local rotational edge restraint, so knot can generates making rigid arm. In other way, did *Coupling type *Kinematic can be use as force/moment not displacement/rotation?
Probably, cause of linear element does not have mid nodes then make it linearised and produce expectable results. It seems not a bug, need further check on slave definition. Actually, i’m also in learning of expanded element and knot or coupling in CalculiX