The Solid Mechanics (Elastic Waves) Interface
The Solid Mechanics (Elastic Waves) interface (), found under the Acoustics>Elastic Waves branch () when adding a physics interface, is a shortcut to add the Solid Mechanics interface which is used to compute the displacement field in solids with propagating elastic waves. The Solid Mechanics interface supports studies in many forms, specifically the dynamic Navier’s equation is solved in the solid in the frequency domain. Dedicated Multiphysics Couplings exist to couple fluid, solid, and porous domains.
When this physics interface is added, these default nodes are also added to the Model Builder Linear Elastic Material, Free, and Initial Values. For 2D axisymmetric components an Axial Symmetry node is also added. Features and boundary conditions are described in the Solid Mechanics documentation.
The Port Condition
The Solid Mechanics interface has functionality and features that are specifically tailored for elastic wave applications. The Port condition allows to set up conditions at the inlet/outlet of elastic waveguide structures that are mathematically consistent. Use the Port to set up non-reflecting conditions, that perform better than a PML, as every propagating modes are captured explicitly.
See the tutorial Mechanical Multiport System: Elastic Wave Propagation in a Small Aluminum Plate. Application Library path: Acoustics_Module/Elastic_Waves/mechanical_multiport_system
Solving Elastic Wave Problems in the Time Domain
When solving elastic wave problems with the Solid Mechanics interface in the time domain it is important to make changes to the Transient Solver Setting section. Expand the section and select the check box Maximum frequency to resolve, then enter the maximum frequency to resolve in the model fmax,sol. The maximum frequency is dictated by the frequency content of the source as well as the eigenmodes of the structure that can be excited. Setting this correctly will results in a transient solver tuned specifically for modeling wave problems.