Add tangent geometric stiffness for the ChElementSpring. Previously only the material tangent stiffness was used, but geometric stiffness can help convergence a lot when studying pre-stressed structures. Also, without it, the eigenvalues (natural frequencies) would be wrong in prestressed structures.
Add tangent geometric stiffness for the ChElementSpring. Previously only the material tangent stiffness was used, but geometric stiffness can help convergence a lot when studying pre-stressed structures. Also, without it, the eigenvalues (natural frequencies) would be wrong in prestressed structures.

Milad-Rakhsha/chrono,dariomangoni/chrono,dariomangoni/chrono,dariomangoni/chrono,projectchrono/chrono,rserban/chrono,dariomangoni/chrono,rserban/chrono,dariomangoni/chrono,rserban/chrono,projectchrono/chrono,rserban/chrono,Milad-Rakhsha/chrono,projectchrono/chrono,projectchrono/chrono,projectchrono/chrono,rserban/chrono,rserban/chrono,Milad-Rakhsha/chrono,rserban/chrono,dariomangoni/chrono,Milad-Rakhsha/chrono,Milad-Rakhsha/chrono,projectchrono/chrono,Milad-Rakhsha/chrono