Hello guys, I need help to do Large mass method using SOL 111, I did modal analysis and I got these rigid and flexible mode,(Units in milimeter, tonns and seconds)
i.e., 00, 15.2, 25.4, 26.2, 27.3, 31.7, 40.9, 41.2, 42.6, 43.7 Hz
I used these cards like
Tabled card: TABLED1 (x1=0,y1=1 and x2=50,y2=1)
Damping card: TABDMP1 structural damping G, (f1=0,g1=0.06 and f2=0,g2=0.06)
Frequency card: FREQ1 (f1=0, df=0.01 and ndf=500), can I add other freq like FREQ3, FREQ4 for excitation frequency?
dynamic load card: RLOAD2
Force: DAREA (F=1e+06 N)
Large mass; CONM2 (M= 1e+06 tonn/kg)
Output request; ACCELERATION(SORT2, PLOT,PHASE)= ALL
My problem is, when I attached springs at four corners and did for modal frequency response analysis using SOL 111
then the rigid and global modes are, 0.0, 1.10, 1.37, 1.52, 15.5, 25.5, 26.4, 27.5, 31.7, 40.9 Hz.
Fundamental freq like 1.10, 1.37 and 1.52, Here my model start vibrating but after when it come to 15 Hz just spring move up and down there is no response on my model, why?, when I look for acceleration at particular nodes it shows in y-direction it start with 0.01 mm/sec2.
model description:
mass=1.478 tonn
spring stiffness, front = 38 N/mm
                        Rear = 35 N/mm
I used spring element as CELAS2 element
BULK DATA: AUTOSPC =YES
                     PARAM POST = -1 or I add any other parameters
so how to get model response above 15 Hz?

By:
PRIYANKAR