Multibody solver for dynamic and static

[tpleece]

Hi ,

I've been using the nonlineardynamicmultibody solver with DynamicCoupled (in SHARPy v1.1.1 (previous discussion)) to look at constrained acceleration/ launch of span-loaded HALE aircraft. I wanted to initially solve for the static deformed shape of the airframe without any aero forces, so tried setting rho to zero, but after a while I always get a singular matrix from Dq = np.linalg.solve(MB_Asys, -MB_Q) in the nonlineardynamicmultibody solver.
Alternatively setting the background velocity to zero causes divergence - possibly due to lack of downstream convection of the wake whilst stationary?

I noticed in the solver folder of v1.1.1 there is a nonlinearstaticmultibody solver, that seems to have been removed from later versions, is there any reason for this and would you recommend using it?

Or is there any other way of solving for the static constrained structural solution before beginning the dynamic coupled part of the simulation? The dynamic part of the multibody problem seems more stable for me, it's just the initial static & acceleration where I'm having problems.

Thanks,

Thomas