Impedance & Periodic Boundaries in Designer

You can apply Periodic and Impedance boundary conditions to your models in the Designer workspace. These boundaries can be selected via the Model Tree.


When using the periodic boundaries however it is important to remember that the opposing boundary condition must be set to free, for example if XMIN is set to periodic then the XMAX boundary condition must be set to free. Don't worry if you forget this as you will be warned before a run if this requirements are not met. If both sides are set to periodic however then the latter will be ignored and the model will perform as expected.

Impedance boundary conditions applies the mass and stiffness values of an infinite load of a given material on the boundaries stated. It will work like an absorber for plane waves across a reasonable frequency range (300% fractional bandwidth), and will be lower performance than ABSR under some conditions, but more stable in general.

Both can be used for fluids and solids, some of the wave types in elastic media will not be properly absorbed with the IMPD condition due to its limitation of primarily working with normal incidence waves.