You can apply loads to a transient magnetic analysis either on the solid model (keypoints, lines, and areas) or on the finite element model (nodes and elements).
To apply boundary conditions (BCs) and loads to a 2D transient magnetic analysis, use the same GUI paths used to apply boundary conditions or loads to a 2D static magnetic analysis. (See 2D Static Magnetic Analysis for details.) Optionally, you can apply loads and boundary conditions using Mechanical APDL commands, and you can specify load step options to the 2D transient magnetic analysis. Alternative Analysis Options and Solution Methods discusses both command-based loading and the load step options.
By definition, a transient analysis involves boundary conditions and loads that are functions of time. To specify such loads and BCs, you need to divide the load-versus-time curve into suitable load steps. Each vertex on the load-time curve can be one load step, as shown in Figure 4.1: Examples of Load-Versus-Time Curves:
For each load step, you need to specify both load or BC values and time values, among with other load step options such as stepped or ramped loads, automatic time stepping, and so on. You then write the load data to a file and repeat this process until all load steps are specified.
See Alternative Analysis Options and Solution Methods for details about the load step options available for 2D transient magnetic analysis.
While the cyclic symmetry capability is used to define periodic boundary conditions in a static analysis, use the PERBC2D macro for transient or harmonic analyses.
Using the PERBC2D macro, you can define periodic boundary conditions automatically for a 2D analysis. PERBC2D writes constraint equations or assigns node coupling necessary for two periodic symmetry planes. To invoke the macro, use either of the following:
Electric and Magnetic Macros discusses and illustrates options for using PERBC2D.
Current (AMPS) is a nodal current load that applies only to massive (solid) conductor regions with an impressed current. It represents the total measurable current flow through the conductor (units of current), and is valid only for 2D planar and axisymmetric models and 3D models. For the 2D elements PLANE13 and PLANE233, this load requires the AZ, VOLT degree of freedom set in the conductor region.
To apply a uniform current load through a cross-section of the skin-effect region, you must couple the VOLT degrees of freedom across that cross-section. To do so, use one of the following:
In 2D planar and axisymmetric models, simply select all nodes in the skin effect region and couple their VOLT DOFs. Use one of the methods below to apply the current to a single node in the cross-section:
You can apply vector potential loads, time-integrated scalar potential loads, current segment loads, Maxwell surface loads, source current density loads, and virtual displacement loads to a transient magnetic analysis. For descriptions of these loads, see 2D Static Magnetic Analysis.