To perform frequency analysis, you need the following:
Meshed model. The model must be meshed before running the analysis. The Node-to-Node and Surface contact conditions are not supported.
Material properties. Note that density is a required material property.
Modes to be extracted. The options depend on the selected solver:
For the Direct Sparse solver, you must specify the Number of frequencies to be calculated. You can optionally specify a frequency of interest in Calculate frequencies closest to. The solver calculates the specified number of frequencies closest to the specified frequency. If no value is specified, the solver calculates the lowest frequencies.
For the FFEPlus solver, you can specify the Number of frequencies or the highest frequency desired. The FFEPlus solver adds rigid body modes (modes with zero frequency) automatically. For example, if you ask for 5 modes of an unsupported model, FFEPlus extracts 6 rigid body modes and 5 flexible modes.
Restraints and loads are optional.
If
you use the Direct Sparse solver,
you must apply adequate restraints or activate the Use
soft spring to stabilize the model option to stabilize the model.
If you use the Automatic solver
option and no restraints are defined, the program uses the FFEPlus
solver.