Hello Karamba Team,

I am a student, I am trying to develop a form finding routine for shell structures under seismic loading. Most of the previous studies have focused on generating equivalent horizontal seismic load and incorporating them into Thrust Network Analysis or Dynamic Relaxation programmes. However, I want to develop a routine where in I take the seismic forces from response spectrum analysis and use those forces to feed it into one of the form finding tools for continuous iterations. However the challenge is to extract these inertial forces at each of the nodes. Karamba does give us the mode shapes and modal participation factors. However I would need the mass matrix to calculate the force vectors for each of the nodes as per the relation:

{f,i} = [m].{phi,i}.G,i.Sa,i

Where, [m] is the mass matrix

{phi,i} is the mode shape vector for ith mode

G,i is the participation factor for ith mode

Sa,i is the spectral acceleration for ith mode time period

And this being a complex curved 3d structure will further complicate the entire process.

Is there any way I can achieve this in Karamba?

Thank you for your support.

Pinaki