Hi

Acoustic elements and acoustic infinite elements support only acoustic (p-waves) while soils carry also many other wave types.

Therefore, truly anechoic boundary conditions for soils require a full blown coupling matrix and data from, e.g. an analytic soil model or from a Boundary Element model.

This was discussed in previous discussions on ResearchGate, e.g.

https://www.researchgate.net/post/How_can_I_use_infinite_elements_for_soil_dynamic

/Claes

Dear Majid

You can use acoustic elements in ABAQUS/CAE for boundary regions and then you can change the name to CIN3D8. This is the best and simplest way.

Dear Mehdi,

Thanks for your answer.

Actually my model is 2D, and the code is CINPE4 (for plastic strain infinite elements) but the main problem is that the infinite elements are compatible with a few elements (i.e the neighbor elements next to infinite elements can't be of any kind). My analysis must be done with pore fluid/stress elements, which are not compatible with infinite elements.

Personally I think that one solution is to use a thin layer of plane strain elements between infinite and pore fluid/stress elements. but still I'm not sure it works !

Gents

The simulation will run, but boundaries will not be anechoic for more than p-waves.

If you want anechoic boundaries, uou need either a full coupling matrix from BE or analytic model or, you can try to physically simulate anechoic wedges as is done here.

Article Experiences from FTF NanoScience Lab. at the University of L...

/Claes

Gents

If your analysis is purely acoustic, Abaqus handles the job as is. If soils are involved, things complicate.

Here are some examples of how the above is implemented in Code Aster. MISS 3D is an analytic code for analysis of multilayered soils.

https://www.code-aster.org/V2/doc/v13/en/man_r/r4/r4.05.01.pdf

http://www-mdp.eng.cam.ac.uk/web/CD/engapps/aster_docs/UDocs-HTML/U20607b/U20607b.pdf.html

https://www.code-aster.org/V2/doc/v13/en/man_v/v2/v2.05.103.pdf

https://www.code-aster.org/V2/spip.php?article619

The procedure is very much the same as for FE-BE fully coupled vibroacoustic analysis, only more dofs are involved in the wave propagation for the soil.

/Claes