Checking your model prior to solving (Acoustics BEM)

You can validate your Simcenter 3D Acoustics BEM model prior to solving.

Model Setup checks at solver export

For general information about the Model Setup check command, see Checking the completeness of your model prior to a solve.

The Model Setup check command includes these checks:

• BEM model — Verifies the correctness of the model for Simcenter 3D Acoustics BEM direct acoustic and indirect acoustic or vibro-acoustic solutions.BEM model checksDescriptionFluid material on acoustic mesh checksA fluid material must be assigned to an acoustic mesh.Only one fluid material is supported in the same Acoustics BEM model.Element orientation checksIn an acoustic mesh, all the element normals of connected elements must be consistent. If two elements are connected to each other, both elements should have the same normal orientation: either inward orientation or outward orientation.Assembly label conflicts checksIn an assembly, no node or element labels should conflict.Structural model checksA structural mesh is necessary for an Acoustics BEM indirect vibro-acoustic solution.

• BEM solution — Verifies the correctness of the solution for Acoustics BEM direct acoustic and indirect acoustic or vibro-acoustic solutions.BEM solution checksDescriptionForcing frequency checksAt least one forcing frequency must be defined.Infinite plane checksNot more than three infinite planes can be defined and they must be perpendicular to each other.Intersection of the infinite plane with the acoustic mesh checksThe infinite plane may not intersect the bounding box of the acoustic mesh. That is, the acoustic mesh must be on only one side of an infinite plane.Structural panel checksPanels must be defined on the structural mesh.Boundary conditions consistency checksEnforced acoustic pressure and normal acoustic velocity boundary conditions must be applied on fluid elements only.Enforced acoustic pressure must be applied to the same elements in each solution step.Enforced acoustic pressure and normal acoustic velocity may not be applied on overlapping surfaces.Acoustic absorbers checksIn indirect BEM, two different acoustic absorbers may not be applied on the same side of the element.In direct BEM, two different acoustic absorbers may not be applied on the same element.An acoustic absorber may be defined only to acoustic elements.Fluid material checksOnly the Direct Complex method is supported for density control for the fluid.Coupling surfaces selection checksIn indirect BEM vibro-acoustic solutions the fluid elements in the fluid-structure interface modeling parameters must belong to the fluid mesh.Structural 2D elements or 3D element faces in the fluid-structure interface modeling parameters must belong to the structural mesh.For the structural interface, 2D structural elements should be present in the model and should be selected in the structural coupling.Microphone selection for pressure as function checkNodes specified in the pressure function (SORT2) must belong to the microphone meshGroup's selection for acoustic power checksSelected groups for acoustic power must be composed only of microphone 2D elementsAggregate load boundary conditions checksIn an indirect vibro-acoustic solution, aggregated boundary condition vibrations must be defined only on structural nodes. For more information, see Separated, aggregated, and file reference loads.

For more information about the validations with regard to element orientation, see Checking and orienting the normals of 2D elements and Checking and orienting the normals of 3D element faces.

Model setup checks for solutions with the Standard, Fast Multipole, or H-Matrix methods

When you run the model setup check only for the indirect acoustic solutions with the Standard, Fast Multipole, or H-Matrix methods, the solver performs the following checks:

• Element types — Checks that the acoustic mesh consists only of triangular elements (TRI3 linear or quadratic acoustic elements). TRI6 acoustic elements are not supported.

• Fluid material — Checks that the speed of sound (c) and mass density (rho) on the exported elements are constant or frequency dependent. Checks that the following inequalities are true:Imaginary part of c >= 0.Imaginary part of rho <= 0.Real parts of both rho and c >=0.

• Infinite planes — Checks that:Only one infinite plane is defined.The infinite plane crosses the origin (zero offset).The infinite plane is symmetric (zero velocity).

• Output requests — Checks that:Acoustic power is not requested on selected groups.Pressure SORT2 results are requested only on microphone nodes.

• Loads and simulation objects — Checks that:For loads, the side selection is always top and bottom.Enforced pressure load is not defined.Dipole sources are not defined.Only rigid transfer admittance is defined.

Where do I find it?

Application	Pre/Post
Prerequisites	A Simulation file as the work part and displayed partAcoustics BEM as the specified solverAcoustic or Vibro-Acoustic as the specified analysis type
Simulation Navigator	Right-click the Solution node → Model Setup Check

Learn more

Acoustics BEM solver environment

Acoustics BEM workflow

Acoustics BEM remote solving workflow (Linux)

Modal-based forced response with vibro-acoustic coupling (Acoustics BEM)

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Checking your model prior to solving (Acoustics BEM), Simcenter 3D 2021.1 Series

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