Comsol Transient Vibration Analysis

[incensus]

hi all..
How can i describe initial conditions or initial forces in comsol(like wave forms such as ramp or parabolic)? I couldn't find it in the manual.
in ansys, i do it in time steps(in solution options).(like t=0, F=10 t=0.001 F=0)
I tried to give initial displacements to the points but it didnt work,either.. It gave ridiculous results..like damped oscillations when there was no damping..
thank you for help..

 

[incensus]

I defined a function for the force input (at the options menu).. i thought it worked.. but still the output waveform is not correct(not a full sinusoid.. a more like saw signal.. and although there is no damping, its a damped signal..) help : \