Setting the Properties of the Study

The Force as well as the Displacement control methods will fail in the neighborhood of turning points for this kind of model. The Arc-Length control method is naturally suitable and will be used for this problem.

In the Arc-Length control method, the pattern of applied loads is proportionally incremented (using a single load multiplier) to achieve equilibrium under the control of a specified length (arc-length) of the equilibrium path. The arc-length will be automatically calculated by the program. No “time” curve is required.

To set the properties of the study:

  1. In the Simulation study tree, right-click the study icon and select Properties.
  2. In the Nonlinear-Static dialog box, on the Solution tab, make sure of the following settings:
    1. Automatic (autostepping) under Time increment.
    2. 0.01 is set for Initial time increment.
    3. Min is set to 1e-08 and Max is set to 0.1.
    4. Use large displacement formulation is selected for Geometry nonlinearity options.
  3. Under Solver, select Automatic.
  4. On the Solution tab, click Advanced Options.
  5. On the Advanced tab, under Method:
    1. Set Control to Arc Length.
    2. Make sure NR (Newton-Raphson) is set for Iterative technique.
  6. Under Arc-Length completion options, do the following:
    1. Make sure that Maximum load-pattern multiplier is set to 1e8.
    2. Type 1e8 for Maximum displacement (for translation DOF).
    3. Type 65 for Maximum number of arc steps.
  7. Under Step/Tolerance options:
    1. Set the Convergence tolerance to 0.0001.
    2. Click OK.