In two parts the article describes physical modeling and numerical simulation of bar deformation under axial compression in the channel. The regularities of nonlinear bending of the rod in the plane have been revealed. Bar shapes were determined by the load history and can differ at the same force value. The problem was to find the shape with the lowest potential energy. The second part of the article describes numerical modeling of gradual loading of the bar with rigid fixing at the ends and unloading the bar with hinges at the ends; physical modeling loading and unloading, as well as overall final comparison of the forms of numerical and physical models. When unloading, deformation occurs in a more variable way compared to loading. The forms remain stable under compressive forces being within the range of existence for loads. Forming symmetrical shape variants differing in the sign of deflections is possible. In the shape-critical state, the bearing pressure becomes minimal. The forms of the physical model under loading and unloading confirm the results of numerical simulation. The results obtained are applicable to the analysis of the state of such bar objects as drilling, casing, pumping and compressor columns and pipelines.