Re: 3D modelisation - seismic aggression

Hello Magic3306

your units are (probably) not compatible:

terre=DEFI_MATERIAU(ELAS=_F(E=3500E6,
NU=.27,
RHO=2000,),);

I guess youngs modules is in MPa or N/mm2, and your density is in kg/m3 and I assume unit length is mm.
So change rho to ton/mm3, ie 2000e-9 and your mass will be in ton.
Or change unit length to m and E to Pa.

BTW: your frequencies will not be in Hz, but in sqrt(1000) Hz, or 1/sqrt(1000) Hz (or a factor alike) because of the same reason.

So: keep to ISO units and marslander will not fail (at least not because of stability issue due to mismatch of units, lots of other problems can be the cause of a failure as well).


kind regards - kees

Hoi Magic

your right.
Just paid too much attention to the x 10⁶ Pa and not to the 3500 in front of it.
I will try to run your problem later this week.

I got this as your total mass: 3.92196E+05 [kg]
at COGX, COGY, COGZ: 3.89200E+00 , 3.99076E+00 , 4.58699E+00 [m]

Roughly calculating by hand (omitting holes at the bottom):
Volume ~ 4*(8-0.8)*9*0.8 ~ 200 [m3]
Mass = 2000*Volume ~ 4e5 [kg]

Back to your question: do you miss 648 kg compared to your hand calculation?

mass_in table:
#total mass of construction
#ASTER 11.00.36 CONCEPT masse_in CALCULE LE 01/02/2012 A 21:16:02 DE TYPE
#TABLE_SDASTER
,LIEU ,ENTITE ,MASSE ,CDG_X ,CDG_Y ,CDG_Z ,IX_G ,IY_G ,IZ_G ,IXY_G ,IXZ_G ,IYZ_G ,IX_PRIN_G ,IY_PRIN_G ,IZ_PRIN_G ,ALPHA ,BETA ,GAMMA
,MAIL ,TOUT , 3.92196E+05 , 3.89200E+00 , 3.99076E+00 , 4.58699E+00 , 6.01028E+06 , 6.06204E+06 , 6.87258E+06 ,-4.85160E+04 , 1.07983E+05 , 1.75790E+04 , 5.97303E+06 , 6.08531E+06 , 6.88656E+06 ,-2.76267E+01 ,-5.55702E+00 , 4.73805E+00