Himayat Ullah's blog

It is difficult to conduct post buckling analysis of thin shell under axial compression using Arc Length method in Ansys.
The Minimum & Maximum Arc Length radii are chosen by hit & trial.When imperfections are incorporated in the FE model,  some times the solution diverges at a higher critical load that the eigen value  buckling, which should be vice versa in actual. Some times , negative eigen values are also shown.

Is there any easy way to solve this nonlinear stability problem?

Himayat

I am analyzing a steel thin walled cylidrical shell subjected to axial compression against buckling.I performed both eigen value linear and nonlinear buckling analyses using ANSYS.The buckling load is less than the material yield limit and is therefore elastic buckling.

One of my colleague argues that the shell will regain its original shape after the buckling load is removed,as its is elastic buckling.My plea is that the shell has passed the limit point (buckling load) and it is global buckling and no shape recovery will occur after the load removal.

Dear All,

I am analyzing a steel pressure vessel with autofretage effect in ANSYS. This effect brings the vessel steel fully plastic in the first load step.After the remval of the load in the second step,a permant strain and residual stress remains in the vessel.The residual stress develops compressive stress in the vessel.