Answer:
To use the Isotropic Masonry 2D material, the RF‑MAT NL add-on module must be licensed. Without this license, only the Isotropic Linear Elastic and Orthotropic Elastic 2D/3D material models are available.
Missing License for Isotropic Masonry 2D in RF-MAT NL
When defining material as "Isotropic Masonry 2D", I get an error message saying the authorization of the program failed.
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