Modifications to the model

For the Plastic model, you will specify the post-yield behavior of the material using the classical metal plasticity model in Abaqus. The initial yield stress at zero plastic strain is 380 MPa. Since you are modeling the steel as perfectly plastic, no other yield stresses are required. You will perform a general, nonlinear simulation because of the nonlinear material behavior in the model.

To add plasticity data to the material model:

1. In the Model Tree, expand the Materials container and double-click Steel.

2. In the material editor, select MechanicalPlasticityPlastic to invoke the classical metal plasticity model. Enter an initial yield stress of 380.E6 with a corresponding initial plastic strain of 0.0.

Edit the step definition and output requests. In the Basic tabbed page of the Edit Step dialog box, accept the total time period of 1.0 and assume that the effects of geometric nonlinearity will not be important in this simulation. In the Incrementation tabbed page, specify an initial increment size that is 20% of the total step time (0.2). This simulation is a static analysis of the lug under extreme loads; you do not know in advance how many increments this simulation may require. The default maximum of 100 increments, however, is reasonably large and should be sufficient for this analysis.

Open the Field Output Requests Manager. Edit the current output request to request the preselected defaults at every increment.

The load applied in this simulation is twice what was applied in the linear elastic simulation of the lug (60 kN vs. 30 kN). Therefore, in the Model Tree, double-click Pressure load underneath the Loads container, and double the magnitude of the pressure applied to the lug (i.e., change the magnitude to 10.0E7).

In the Model Tree, create a job named PlasticLugNoHard, and enter the following job description: Elastic-Plastic Steel Connecting Lug. Remember to save your model database file.

Submit the job for analysis, and monitor the solution progress. Correct any modeling errors, and investigate the source of any warning messages. This analysis should terminate prematurely; the reasons are discussed in the following section.