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non-linear analisys


I am trying to make a structural static non-linear analisys of a thin tube 0.8mm, 0.1mm thickness, 0,05mm mesh size, with a 16Gb ram, xeon-E5 3.7Ghz computer.


I started this simulation 52 hours ago, and it still running, you guys think that it is normal? Or maybe, there is something wrong with my model, or set?




Re: non-linear analisys

Solution Partner Phenom Solution Partner Phenom
Solution Partner Phenom


A few suggestions:


Every nonlinear analysis should be preceded by a linear analysis, simply to check that the model has been set up correctly. The linear analysis results will highlight many important factors
such as the proper application of boundary conditions, deletion of all degrees of freedom without stiffness, the quality of the finite element mesh, etc.
• If the use of a sufficient number of load steps and equilibrium iterations with tight convergence tolerances at each load step is considered to yield an accurate solution of the model, then the basic aim is to obtain a response prediction close to this accurate one at as small a solution cost as possible.

It is helpful to know if the model softens or hardens under increasing load. Structures can soften due to the spread of plasticity, and they can soften or harden due to geometric nonlinear effects (large displacement effects, implane effects, etc..). Contact usually leads to hardening.

• Displacement controlled loading generally converges faster than force controlled loading.

• In general, it is most convenient to use a reasonable number of load steps together with the ATS (Automatic Time Stepping) method.


Good luck!.
Best regads,


Blas Molero Hidalgo, Ingeniero Industrial, Director
Blog Femap-NX Nastran:

Re: non-linear analisys


ok, Thank you so much for your attention!