STABILITY OF A DIRECT RODE FROM POROUS MATERIAL, ONE END OF WHICH IS FIXED HARMONY AND ANOTHER HARD

The problem of loss of stability of a straight rod with a rectangular cross section is considered in the article. One end of the rod is hinged and the other end is rigid. The material of the rod is porous. Therefore, the deformations and stresses are non-linear. The geometric nonlinearity in one of the transverse directions is also taken into account. Thus, the problem is both physically and geometrically nonlinear, hence its solution is associated with great mathematical difficulties. To eliminate these difficulties, a variational principle is applied in solving the problem. The Euler equations of the proposed functional give a system of nonlinear differential equations, which is solved using the fourth-order Runge-Kutta method. The dependencies of the critical values of the compressive force on the initial deflection of the relative length are plotted graphically.