3DEC eigen modes error

Hi. I’m trying to run eigenvalue analysis using the block dynamic eigen command but after the stiffness and diagonal mass were calculated, I got this error:

— Global cycle limit of 1 met.

  current cycle count =        1
  current mech. time  =   1.020E-07
  clock date/time :  1-Feb-23  4:04:36

— Cycling ended at: 2023-02-01 04:04:36
3dec>block dynamic eigen modes 10
no. grid-points 19568
no. stiffness equations 58704
stiffness matrix bandwidth 19272
stiffness matrix size 1131343488
min. diag. stiffness 32999351.1519793
max. diag. stiffness 725125667479.792
min. diag. mass 5.114943717334995E-005
max. diag. mass 144.420088800000
error : fekmodes : w2n<=0 , n 1

Any ideas as to what happened there?

@jvlemos can you help with this one?

Maybe a numerical error due to very small masses.
Are these deformable blocks?

Dear Jim and Jose,

Thank you for your swift responses.

Yes they are deformable blocks but one thing to note for the previous model is that when I generated the block zones, I turned off the gridpoint-match command so that smaller blocks discretization would not affect the bigger blocks that were connected to them. I did not know if turning off the gridpoint-match command would have caused the issue but once I turned it back on and refined the smaller blocks, the problem seemed to have disappeared.

This is the discretization with gridpoint-match command turned off

This is the discretization with gridpoint-match command turned on