How to model a varying point load?

[stav1987]

I am trying to model a point load in the middle of a steel plate. The load must change over time, initially it will be 1GN then it must increase to 4GN and then ease off back to the constant 1GN (the force should act like a parabola when increasing and easing off).
I tried to model this in a transient analysis but was unable to do so.

What analysis type would you use?
How would you apply the load?

Any help would be greatly appreciated, the method may be simple but I am fairly new to ANSYS.

 

[flash3780]

I just have a couple of suggestions:
A. Try turning on auto time stepping. This often helps with convergence of dynamic problems.
B. If inertial effects aren't significant in your problem, consider using a static structural analysis with a varying load over several load steps.
C. A point load may be causing convergence issues, especially with the magnitude of the load that you're applying. Try spreading the load out onto several nodes if possible. For example, the load might be applied to a small circular patch.

 

[SFLM]

Stac1987,

To do what you need, you must use a table to apply the load.

Whether the analysis is transient ou static, it depends on what you want as a result. They both can be used.

remeber: a load that varies over time is applied by means of a table.

Cheers.

Steve

 

[stav1987]

SFLM
do you by any chance have a tutorial explaining how to input a time variant load in table form because I have looked in ANSYS help and that seemed to confuse me more (via the GUI interface)

 

[stav1987]

SFLM
I realise that applying the time varying load via a table is the way to go. However, on creating a 1-D table with TIME as VAR1 and FZ (or FORCE). I then edit the Table and input the time and force required.

On applying the load on a node of my model ANSYS produces an error, stating 'missing parameter = FZ' .

Cheers
Stavros