Steady state dynamics and structural damping

General Questions
1

Greetings,

When performing steady state dynamics (SSD) using structural damping in the material definition, and damping type “off” in the SSD step the simulations take way longer compared to just using constant damping ratio in the SSD step. Is SSD still using modal super position of structural damping is used instead of viscous damping defined by constant damping ratio?

Thanks!

2

SSD supports the following independent forms of damping:

  • Rayleigh (global damping parameters) or direct (viscous damping factor for each mode) damping with *MODAL DAMPING
  • structural (material) damping with *DAMPING
  • dashpot damping if dashpot elements are used

Disabling damping in SSD step settings only affects *MODAL DAMPING, not the material level one.

3

Thanks for your reply!

In case material structural damping is included, does SSD still use modal superposition, or direct solving of the equations at each frequency?

4

SSD in CalculiX is always based on modal superposition (unlike in Abaqus where you can choose direct or subspace based version).

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