adsorbing boundary 3d results

[GiorgioAltin]

In the attached model we would study the modification of the seismic behavior of the soil as a function of the modifications imposed on the geotechnical characteristics. The attached input file concerns the first step with linear elastic analysis, which finish without any problem but it is clear that the vertical acceleration component does not propagate as it should. Something is wrong. The monitor function for the top nodes doesn't register any acceleration.
Do you have any suggestion?
Thank you
Giorgio Altin

[STKO Team]

• Don't use Integrator TRBDF2 with -factorOnce (in the Linear system). Use Newmark or switch off -factorOnce. This is an implementation issue of the TRBDF2.
• Your mesh size in the Z direction (propagation of the wave) should be small enough to let the wave travel in the mesh.
  The mesh size MUST be < Vs/Fmax/8.
  With:
  • Vs = sqrt(G/rho)
  • Fmax is the max frequency of your input (it should be 10 Hz in your case)
  In your model the max mesh size in the Z direction should be about 0.02 meters...