apply force in every axis nonlinear analysis

[Vicot34]

Hi,

I am doing nonlinear static with NX Nastran to determine the shape of a overhead substation conductor. Based on different litterature on the subject i model my conductor as a beam element. i Run different case to reach my final shape. First, i apply the weight as a load, second i apply node displacement and rotation to my constrained node. So far everything works well. i have only worked on the x and y plane. The problem is when i try to apply a wind force on the z plane i am not able to make it converge. It crash after the first iteration of that case. I have realized that i am not even able to make a displacement of a node in the z axis. i am using newton raphson solver.

Can anyone help me determine why i cannot apply force or displacement in the z axis?

Thanks for your help

 

[BlasMolero]

Dear Vicot34,
Without the FEMAP model in hand is difficult to know the reason of the error, post it here and we will take a look to it.
I understand when you say "I apply a load in Z and solver crash" it means that you changed the boundary conditions compared with the case that solve Ok in the X-Y plane. Please check your model solves OK in a linear static analysis, to me you have a rigid body motion that cause singular stiffness matrix.

In nonlinear analysis in problems controlled by load or enforced displacement when the solver do not converge one reason could be that increasing load or displacement is not possible because the finite element model experience a negative load (buckling) or negative displacement (snap-back, snap-through), in this case the only solution to get the nonlinear problem converged is using ARC-LENGTH control, the Modified Riks is my preferred method.

Best regards,
Blas.

~~~~~~~~~~~~~~~~~~~~~~
Blas Molero Hidalgo
Ingeniero Industrial
Director

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[rb1957]

is Zed axial ?

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.