Derived Load Cases

In this section, you will learn how to use the Derived Load Case tool to create derived load cases. The types of derived load cases that can be created are Steps, Linear-Superposition and Envelope.

To access the Derived Load Case utility, select Results > Create > Derived Load Steps from the menu bar. You can also select the Derived Load Cases button in the Results toolbar or right click in the Results Browser or graphics area and select Create > Derived Load Case > Steps (or Linear-Superposition or Envelope).

Steps

When the Type is set to Steps, this allows you to create a derived loadstep from other loadsteps. A derived loadstep can contain more than one simulation step, with scale factors optionally applied to them. Basically, the loadsteps are appended in the order they are listed to create the derived loadstep. You can select simulation steps from the loadstep list by selecting them with your mouse or the arrow keys. Use the and buttons, to add or remove the required loadsteps/simulations to the derived loadstep. Below is an example where Subcase 1, Subcase 2, and Subcase 3 have been added to the Derived load case named Deriv_1. Notice that the Type is set to Steps.

Linear-Superposition

The Linear-Superposition type is used to create loadsteps that are linear combinations of other loadsteps. Once the Type is set to Linear-Superposition and the desired loadsteps are selected, a scale factor can be applied to each loadstep. Below is an example where three loadsteps are selected and each have a different scale factor applied.

Envelope

The last type is the Envelope option. This option allows you to create a derived loadstep, which compares entity values and stores desired values from selected loadsteps (or animations) based on the Min/Max/Extreme option that is chosen.

When Min is selected, the minimum values among all the selected loadsteps or simulations are found. Max finds the maximum values amoung all selected loadsteps or simulations. The Extreme option finds the maximum absolute value among all the selected loadsteps or simulations. Below an Envelope derived loadcase is created which searches for the maximum value in Subcase 1 and Subcase 2.

Within the Create/Edit Derived Load Case dialog, there is the View Derived Load Cases button, . This button changes the tree listing the available loadcases so that the derived load cases are listed (as shown below).

Once the derived load case has been created, it is now available for selection in the Results Browser, as shown below.