Applying loads and supports for a cyclic Full Harmonic Response analysis (standalone and pre-stressed) follows the same requirements as those outlined in the Harmonic Response Analysis and Harmonic Response (Full) Analysis Using Pre-Stressed Structural System sections of the Mechanical Help except for the requirements and restrictions discussed below.
General Loading Application Requirements
The following support limitations and specifications must be observed for a standalone (Full) Harmonic Response analysis when cyclic symmetry is defined:
The following boundary conditions are not supported:
Bearing Load
Rotating Force
Incident Wave Source
Port In Duct
Diffuse Sound Field
The following remote boundary conditions are not supported:
Joints
Bearing
Inertial boundary conditions as well as the Moment boundary condition are restricted to the axial direction. Therefore, you must set the Define By property of the specified boundary conditions to Components. Only the Z Component property can be non-zero and the Z-Axis of the specified Coordinate System of the boundary condition must match the coordinate system used by the corresponding Cyclic Region. In similar fashion, you must define the Remote Point for Moment loads so that its points of application lie along the cyclic axis.
Elastic Supports and Compression Only Supports are not available.
Make sure that you do not scope a Remote Displacement, Remote Force, or a Moment to a geometric entity that shares an edge, vertex, or node with either the specified High Boundary or Low Boundary properties of the Cyclic Region because the application could generate incorrect results.
Specified Remote Points cannot coincide with the cyclic symmetry axis, as this could generate incorrect results. However, there are exceptions for a standalone modal or an MSUP modal analysis. If the analysis includes a Displacement or a Moment (for a subsequent MSUP) that is applied about the cyclic symmetry axis and then to all sectors, then the Displacement or Moment:
Must be scoped to a Remote Point that has its Behavior property set to Deformable.
Must have all DOFs fixed except the DOF about the cyclic symmetry axis, and,
The specified Remote Point must lie on the cyclic axis of symmetry.
Note: If you specify a Fluid Solid Interface load, you could expose non-physical results if the remote boundary conditions have their Behavior property set to .
Additional restrictions apply while specifying supports for a cyclic Harmonic Response (Full) analysis. Also, the loads and supports should not include any face selections (for example, on 3D solids) that already belong to either the low or high boundaries of the cyclic symmetry sector. Loads and supports may include edges (for example, on 3D solids) on those boundaries, however.
By default, loads and supports are assumed to have the same spatial relation for the cyclic axis in all sectors. Also the loads and supports defined in Mechanical are applied for each and every sector by Mechanical APDL.
Non-Cyclic Loading
For Full Harmonic Analysis, you can specify non-cyclic loading to excite a specific harmonic index or indices for the following loads. These loads include the Non-Cyclic Loading Type property. This property enables you to specify harmonic indices to be excited by the load. See the Non-Cyclic Loading section for additional information.
Force (applied to a face, edge, or vertex)
Recommendation: Ansys recommends that you do not define remote boundary conditions along the cyclic axis of symmetry when you have specified non-cyclic loads.
Boundary Condition Conversion to Node Constraints
In preparation for solution, the boundary conditions on the geometry are converted into node constraints in the mesh (see Converting Boundary Conditions to Nodal DOF Constraints (Mechanical APDL Solver) for more information). When these boundary conditions involve nodes along the sector boundaries (low, high, and axial boundaries), their constraints are integrated to properly reflect the symmetry. As an example, the low and high edges may feature more node constraints than are applied to each individually, in order to remain consistent with an equivalent full model.