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7-Bedrock

Displacement function of time

Hello,

I would like to define a determined displacement for a body in the function of time (see attached picture). At the moment, only the fix value is active for the displacement.

How can I define it?

Thanks

Roland

4 REPLIES 4
17-Peridot
(To:rrakos)

What are you talking about?

Creo Simulate/Mechanica or Mechanism?

In Mechanism do it is very simple, in Simulate you have to define a Dynamic Time Analysis.

7-Bedrock
(To:gfraulini)

Sorry....I am talking about the Simulate Mechanica.

I defined a time dependent value in the Static Analysis Definition. This time function is multiplied with the displacement value.

Is is correct?

Thanks

Roland

17-Peridot
(To:rrakos)

If I remember well, in a Static Analysis you can't define a load history without nonlinear option such:

1. contacts,
2. nonlinear material,
3. large deformations.

In my opinion, within a static analysis speaking of the time dependence of load/displacements is deceptive because you don't see the"modal" response of the structure that requires a Dynamic Analysis (time or frequency).

In my experience, I've use SA with time dependence only with the ramp and a lot of measure points to obtain a better convergence of a non linear analysis as the three points above.

I'm open to other points of view!

12-Amethyst
(To:rrakos)

If this is a static analysis.

Giulio is right, you would need to invoke large deformation or some other non-linearity to be able to use 'timesteps'.

You are correct, time functions multiply the constraint (and loads)

The order of load application is unimportant unless you are considering plastic and/or friction

The question then becomes ... Does it have to be so complicated?

Is the analysis at each timestep linear (or linear enough)?

If it is then do a number of individual simple studies with different enforced displacements. Much easier. Batch them up and go for lunch.

You could be a bit cleverer and make the enforced displacement value a parameter and use standard design studies.

If you still want timesteps then fool the software by creating a 'dummy contact' somewhere, (a contact that does nothing because it never touches). Avoid using large deformations as this will be expensive.

Keep it simple if you can. Much easier to debug

bfn

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