I need to do a analysis in which a disk is rotating from 1000 rpm to 3000 rpm with some constant acceleration value and I have to check what will be centrifugal stress variation with time. Can anyone tell how this will happen?
If your acceleration if low (regarding your disc dynamics), you can perform a series of static computation, using prescribed loads corresponding to the rotating effect. There are examples in the analysis manual (search for gyroscopic effects).
If not, you will have to consider a transient simulation with proper defintion of the rotation movement in the boundary conditions.