This example attempts to exemplify the use of the History plot utility. This tool is very useful in case of solving a model which has generated more than a single load case result. This happens, for example, in: transients, modals or even harmonics analysis. Our model will be carried out by means of a Transient analysis.
The target is testing how a particular result depends on another variable that can be: another result or even the time.
In the next example, a steel beam 1 meter long will be shaped. On the other hand, the material behavior will be a bilinear one. This means that, the stress-strain diagram is shaped in the appearance ahead.
Here it is the beam visualization. The section type which performs the beam structure will be a IPE240:
The applied loads will be specified ahead:
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LoadGroup: punctual load of 1.0e7 N at the end of the beam. This load depends on time, that is, the model has been developed in a transient analysis. As a result of this, the load has been performed with a value of 0 at 0 seconds but 1e6 N at the end of the analysis.
The beam is embedded in one of its endings :
Once the Load Case has been performed, entering both the punctual load and the boundary conditions, the next step is solving the model. When results have been obtained, it is necessary to enter them on the history plot. The target would be trying to find out when the equivalent plastic strain defers from 0. This will be carried out comparing the equivalent plastic strain to time.
The result has been given in the embedded node, that is, in the initial spam. Element 1, end 1 IP 0.
Being the Equivalent plastic strain vs time results ahead:
How it can be seen, the beam starts plasticizing at 0.8 s, that is, in the Load Case number 80.
On the other hand, it would be available as well testing from which stress the beam starts plasticizing. This will be get comparing the von Mises stress with the total strain result.
Being the total strain vs von Mises results ahead:
So as to clarify the example and show the chart clearer, as we know by the previous graph that the beam starts plasticizing at load case 80, they have been only visualized the first 82 Load Cases, taking the chart the appearance above.
The yield strength would be 235 MPa, how the image shows in the chart. That is just the same value the material properties take into consideration for the yield stress "fy":
Thus, the example has been properly developed trying to offer to the user, a new perspective in relation to the results plotting and listing.
