Force vs Displacement Plot 1

[gatre]

I performed a tensile test with dog-bone specimen. The true stress and strain plot is quite good with experiment. I want to plot graphic of history of Force vs Displacement to compare with experiment.

How can i do this?

I tried to plot RT (or RF ) Vs U (UT) in ODB Field Output but the force is always zero at center of specimen.

Regards

 

[gurmeet2003]

I am assuming that you have one end of specimen fixed. Sum the reactions at this end and plot them vs. displacement.

Gurmeet

 

[gatre]

Thanks Gurmeet very much.

 

[gatre]

I checked reaction force at fixed part and knew that it is so small. RF and RT are same value. What is difference between these reaction force.

What do you mean Sum the reaction force?

Thanks

 

[gurmeet2003]

RF only gives reaction forces. RT gives both forces and moments. Reaction forces are calculated at each node. If you query your results for Reaction forces, the values at each node will be displayed. You want to plot applied force vs. displacement. In order to obtain the magnitude of applied force you need the value of total reaction forces. This is why you have to sum the nodal reactions in the desired direction. Therefore sum the individual components and not the magnitude.

In order to sum, first you have to retrieve the values of nodal reactions. To do this:

1. Go to tools>x-y data> create>odb field output > continue to x-y data from odb field output> set position to unique nodal>click on required component of RF> click elements/nodes tab> click pick from viewport>click edit selection> pick the desired nodes in graphic view> click done and then save.
2. Go to tools>x-y data> create> operate on x-y data> pick the SUM() operator> select the nodes from the table>add>save

First step will write the x-y data to a table and save it. The second step will add all the reactions and save the Reactions for each converged iteration in a table. Now you can view the reactions as well as plot them.

Gurmeet

 

[rm2]

I am doing basically the same thing. I did the SUM at the end nodes from the fixed part, but I am having trouble understanding the low forces of the plot.
The modulus of elasticity units are Pa, the model should be in mm, I guess what I am seeing is microNewtons, which really does not makes sense to me...
If necessary I can provide abaqus file so you can take a look,
how do you add to the x axis the displacement to the plot?

thanks

 

[rm2]

upps forgot to attach the photo

 

[gatre]

Thanks for Gurmmeet,
Following your guides, the graphic showed a shape corresponding well with experiments but its max value (3500N) is higher two times than the experiment(1700N).

The specimen is meshed into 2 layers, 16 elements in width. So, I have 51 nodes in cross section at the fixed end. I selected 51 nodes and results as above. This results is for two layers? Do I need to divide to 2 ?
Thank for your reply.
Regards