Hello
Could you please upload your defective SSD project? I can not recreate the error message with the latest SOFiSTiK Version 2022.
Otherwise check the mentioned TEDDY Example.
TEDDY > File > Examples > textile > english > membran_poisson_ratio.dat
Best regards
Frederik Höller
Your SOFiSTiK Support Team
As described within the error message, the factor
1 - muexy ⋅ mueyx = 1 - muexy ⋅ muexy ⋅ E/E90 = 1-0,33⋅0,33⋅157,9/9,584 = -0,794
gets negative. Please increase the anisotropic E-Modul (E90). The reason for this behaviour is described within the AQUA manual.
SSD / TEDDY > Help > User Manuals > All Manuals… > AQUA > chapter 3.7 MATE - Material Properties, page 3-37
And you should read the comments in the mentioned TEDDY example.
TEDDY > File > Examples > ase > english > membranes > membrane_poisson_ratio.dat
Best regards
Frederik Höller
Your SOFiSTiK Support Team