When a non-conformal mesh presents on the interfaces between regions in an acoustic analysis, insert contact elements at the interfaces to bond the regions together.
If elements in the different regions have different numbers of DOFs on each node, define the contact surface (CONTA174) on the elements with more DOFs per node and the target surface (TARGE170) on the elements with fewer DOFs per node.
The following table lists the contact element settings to use with the various acoustic methods.
Table 11.4: Contact Element Settings for Acoustic Modules
| Contact Surface on ... | Target Surface on ... | CONTA174 KEYOPT(1) Setting |
|---|---|---|
|
Helmholtz Acoustics (KEYOPT(2) = 0 or 1) | Elastic Structure | 0 (UX, UY, UZ) |
| Helmholtz Acoustics | 10 (PRES) | |
|
Viscous Thermal Acoustics (KEYOPT(2) = 5 or 6) | Elastic Structure | 0 (UX, UY, UZ) |
| Helmholtz Acoustics | 10 (PRES) | |
| Viscous Thermal Acoustics | Not Available | |
|
Poroelastic Acoustics (KEYOPT(2) = 7) | Helmholtz Acoustics | 10 (PRES) |
| Elastic Structure | 0 (UX, UY, UZ) | |
| Poroelastic Acoustics | 8 (UX, UY, UZ, PRES) | |
|
Diffuse Energy Acoustics (KEYOPT(2) = 4) | Diffuse Energy Acoustics | Not Available |
If the contact surface bonds the acoustic elements, set the CONTA174 KEYOPTs as: KEYOPT(2) = 2, KEYOPT(4) = 3, KEYOPT(8) = 2, and KEYOPT(12) = 5.
If the target surface bonds the structural elements, set the TARGE170 KEYOPT(5) = 1.
For more information about defining contact surfaces, see Surface-to-Surface Contact (Pair-Based) in the Contact Technology Guide.