Ok Mr. Richard, I already restrain all six degrees of freedom in the system and doesn´t show the error message, but when the dynamic run begins for Earthquake (Spectrum), the Sturm sequence is failure because the first frequency calculated exceeds the cutoff frequency. There are too high!! This is the spectrum data points:
N Range (s) [Linear] Ordinate (mm/s2) [Linear]
1 0.01 16314.03
2 0.10 33010.65
3 0.20 39298.86
4 0.30 34668.54
5 0.40 29753.73
6 0.50 25015.50
7 0.75 17295.03
8 1.00 12870.72
9 2.00 5395.50
10 4.00 1912.95
What does it mean?
I appreciate your help...
Cesar Moreno