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Modelling changing force over time
2

Modelling changing force over time

Modelling changing force over time

(OP)
Hi,

I am hoping someone can help me as i am stuck. I performed a lab experiment whereby a simply supported I-Beam was subjected to an varying force over time. Force was increased to a max load and then returned back to 0.

I am trying to now model this via ABAQUS and can model the I-Beam fine but don't know how to model the load to change over a time period.

The results i have from the lab display 4 columns: Force, Displacement, Longitudinal Strain and Transverse Strain. The time period between each reading from the lab is 2 seconds. I have a total of 193 rows, therefore the test lasted 384 seconds (i.e. 2*193).

Can anyhow advise me how to model the load to change from 0 to max load back to 0 over a period of 384 secs?

Many thanks

RE: Modelling changing force over time

In the step definition set the length to be 384.  Create an amplitude that has the following values:
0 0
193 1
384 0
Now have your load reference this amplitude and have the load be the max load.

Output results very 2 seconds.

FYI If this is a linear static problem then you only need to apply linear superposition to obtain all the other values.

I hope this helps.

Rob Stupplebeen

RE: Modelling changing force over time

(OP)
Many thanks mate, i'm going to give it a bash :)

RE: Modelling changing force over time

(OP)
Many thanks mate that has done the trick, much appreciated, i made a typo before it was meant to be 386secs :)

Just a quick one, is it possible to output all results (i.e. every 2 seconds) in a tabulated form?

Cheers,
Gerry

RE: Modelling changing force over time

All results?  If you want a specific node or node set use *nodeprint (syntax?) to send the data to the *.dat text file.  Otherwise you can choose the output resolution with your output parameters.

Rob Stupplebeen

RE: Modelling changing force over time

(OP)
I mean for example to gain displacement results for one node over the whole experiment, i.e displacement results every 2 seconds.

At the moment i can only get the result at one time point, if that makes sense mate.

RE: Modelling changing force over time

Try Tools->XY Data-> Create->ODB Field Output->Unique Nodal-> U: and then select the nodes.  I hope this helps.

Rob Stupplebeen

RE: Modelling changing force over time

(OP)
Thanks Rob you're an absolute ledge.

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