Derived data collection

The derived data collections enable to define data collections by applying an operation on one (or several) existing collections. These derived collections are divided in three types:

• Fourier transformations, obtained applying an FFT algorithm to the values of a collection. Only the collections defined on a time interval are compatible. The created collection inherits of the transformed collection support. The user:
  • should specify the specific step interval,
  • can tick or not the option "Automatic duplication of forces for rotating machines". If activated, this option reconstructs the FFT on all the periodicities of the device (e.g. the full device), allowing the user to reduce the number of scenario time steps to solve. In order that this duplication can be performed, the solved scenario must cover at least one electrical period of the device and the selected step interval must be a whole submultiple of the mechanical period, so as that the force values at the first and the last interval step are identical. Moreover, the device has not to be studied during its acceleration phases (ex. no coupled load), since the speed of the rotating mechanical set must be constant.
• Simple operators, enabling to extract the different values, Maximum, Minimum,Average (statistics), Sum or RMS Values of a multi-steps collection. Single step collections are not compatible. The created collection inherits of the transformed collection support. The user should specify:
  • a specific step interval,
  • the operator to apply.
• Harmonic excitations, which allows to define a collection similar to the collections obtained by Fourier transform, but by defining directly different components values (continuous and harmonic) through the combination of other collections values. The chosen collections to compose this type of collection must share the same support and a same data type (nodal or elementary, scalar or vectorial). The created collection inherits of the transformed collections support. The user should specify:
  • a collection defining the continuous component. This collection values should be reals,
  • a collection defining the harmonic component. This collection values should be complexes,
  • a frequency associated to the harmonic.