The input listing for Buckling of a Bar with Hinged Ends is found here: vm127.dat with a description of the example VM127- Buckling of a Bar with Hinged Ends (Line Elements).

This example compares the solution obtained via PSTRES with the solution calculated by the preferred method, linear perturbation eigenvalue buckling analysis with a linear base case. Both methods produce the same results, as expected, because the solution procedure used by Mechanical APDL for linear perturbation eigenvalue buckling analysis when the base case is linear is similar to that used for the linear eigenvalue buckling analysis set up via PSTRES.

For more information about the linear perturbation eigenvalue buckling analysis method, including also the solution procedure when the base case is nonlinear, see Second Phase - Eigenvalue Buckling Analysis and Eigenvalue Buckling Analysis Based on Linear Perturbation in the Theory Reference.