Application of loading and unloading in Abaqus

[ami143]

Dear All,

Can anyone please give me a method how to apply loading and unoading in Abaqus. I would like to apply an elastic model. I have for example 2D plate element, I want to apply a displaceemnt until it reaches for example 1 mm, after that unloading should be applied until the initial displacement zero value. After the unloading phase, I want to make the element in rest period in which no loading is applied, when it reaches a certain period of time, I want to apply loading again. The load history that I want to apply resembles to the following figure (time values are only example in this figure).

I would be thankful if someone can explain how to do it in abaqus.
Thank you!

 

[IceBreakerSours]

Look in to *Amplitude

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[rroaa]

Your load is time-dependent therefore use dynamic,implicit step type.

You may apply this load with tabular data;

Create boundary condition in load module. But when selecting step in boundary condition, choose your first step name. Don't select "initial" step. If you select initial step, software doesn't allow you apply displacement values.)

In boundary condition window create an *amplitude with tabular data like this;

time displacement
0 0
200 1000
400 0
800 0
1200 1000
.... ....

 

[Mustaine3]

> Your load is time-dependent therefore use dynamic,implicit step type.

No. When the reaction is time dependent (inertia), then you need a dynamic step.

 

[ami143]

Hi all,
Thanly for your reply, can I use dynamic explicit for this type of loading ?

 

[IceBreakerSours]

Implicit and explicit numerical schemes are for solving dynamic equations of equilibrium (a variational equivalent of F=ma). In principle, either scheme should give the exact same response and software vendors go to great lengths to show that in many cases. Practical considerations force an analyst to choose one scheme over the other.

The real question for you is if inertia plays a role (to introduce dynamics) and which scheme (implicit or explicit) you should choose.

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[ami143]

thanks again for your respponse
it is not important to me take into account inertia in my analysis.
I tried to use amplitude in dynamic explicit but I did not get the required response for the damage model. Maybe there is problem of stability ?

 

[IceBreakerSours]

You need expert supervision.

Now, what phenomenon are you trying to capture? Please explain the physics and the model set-up as best as you can geometry/mesh/materials/constraints/BCs/loads/..

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[ami143]

Thanks again for your response.
What I need is to apply an isotropic damage model on 2D plate element under tensile loading. The element is restrained in one side and subjected to tensile load in the opposite side. The loading history should be varied with time; loading, unloading, and reloading. I hope that someone can give me some hints.