Features of Nonlinear Calculation of Bending Rods Partially Supported on Elastic Foundation

The paper investigates the results of solving spatial contact problems on the free support of bending rods (hereinafter referred to as beams) on elastic quarter-space and octant of space. The objectives of the study include determining the stress state of contact pads, obtaining a picture of the distribution of contact stresses over them, and studying the features that arise when solving these contact problems. The main solution method is the method of B. N. Zhemochkin, based on the discretization of contact areas by replacing a continuous contact with a point one. This approach allows us to reduce the contact problem to the calculation of a statically indeterminate system using well-developed methods of structural mechanics. The mathematical model of the contact problems to be solved is built on the assumption of linear elastic (geometric and physical linearity) work of both the bending element and the elastic foundation. Since in the process of deformation the end sections of the beam element can break away from the support areas, the contact problems to be solved belong to the group of contact problems with a previously unknown contact area. The design schemes of such problems are constructively nonlinear, and their calculation is carried out by iterative methods. Based on the results of solving the considered contact problems, it has been found that with a geometrically symmetrical support of the beam element on the left and right on elastic quarter-spaces (space octants) with equal support areas, but different mechanical characteristics, as well as symmetrical loading, the values of support reactions, considering them as resultants of contact stresses on the left and right contact pads, and the coordinates of the points of their application are not equal to each other. The solution of the contact problem leads to a similar result in the case of a bending beam element resting on the elastic quarter-space on one side, and on the edge of the space octant on the other. In addition, a constant torque appears along the entire length of the beam element, indicating that the beam element is in a torsional transverse bending condition.