sun 105 nastran - eigenvectors all null

[guido84]

Bye to all,

I came across a problem with buckling:
I did a buckling analysis (sol105) and despite apparently there would be no problem, (no fatal, no "strange" warnings, autovalues other than zero) the motorists are all null.
Note that the same model (differs only for the presence of some rbe2) for other load cases provided non-nuclear motors; Moreover, the movements related to the static solution of the buckling are the same found with the sol101.
Does anyone know how to tell me how to get out?
Thank you.

guide

 

[guido84]

for those interested I found the solution:
just set the autospc=yes param.

I don't know why, but it worked; the autovalues are the same found before, but the motorists are no longer null

 

[Onda]

simply because you had untied knots you stuck with autospc.
try to see in your model if you have free knots to which the mass is not associated.
wave

 

[guido84]

I'll try to control, but by doing a modal I didn't find anything strange