AC and DC solenoid coils are quite different and using AC coils on DC will cause over-current. AC coils rely upon inductance to control the current they demand (Xl) which is dependent upon inductance and frequency whereas DC coils rely upon the coil resistance (R).
Perhaps you could further illustrate what it is you are trying to do, possibly with a drawing
As Doug has suggested, getting a DC solenoid to vibrate at 30Hz will be difficult due to mechanical inertia. Applying 30Hz to 48VAC solenoid rated at either 50 or 60Hz will almost certainly cause a 'heat' issue.
Note also that an AC solenoid does not vibrate at the excitation frequency (50 or 60Hz) as it is specifically design to avoid such vibration.