Dear all,

I am running an FSI simulation in Ansys. I assigned hyperelastic material properties to my structure. Everything is going well and I got good results(Two-way steady-state FSI simulation).

Once I change the material properties, to a hyperelastic Neo-Hookean material model while decreasing the initial shear modulus \mu value. The solver aborts within the first iteration and I receive the following error messages :

1- (DP 0) The solver engine was unable to converge on a solution for the nonlinear problem as constrained.

2- (DP 0) Element ## located in Body "Solid body2\Solid_membrane\Solid body2\Solid_membrane" (and maybe other elements) has become highly distorted. You may select the offending object and/or geometry via RMB on this warning in the Messages window. Excessive distortion of elements is usually a symptom indicating the need for corrective action elsewhere.

3- Update failed for the Solution component in System Coupling. The coupled update for system Static Structural threw an exception. Error updating cell Solution in system Static Structural.

Under-relaxation parameter manipulation, Linear ramping within the system coupling module did not solve the issue. I'm not sure if playing with substep parameters would help, However, I think the problem has something to do with Newton-Raphson approximation method.

Would running a transient simulation help ?

Any help or recommendation would be highly welcomed!

Thank you!