ESTIMATION OF ALLOWABLE LOAD IN LONGITUDINAL COMPRESSION STRAIGHT ELASTIC ROD
DOI:
https://doi.org/10.36773/1818-1112-2025-136-1-110-115Keywords:
stability, yield strength, critical strain, allowable load, imperfection levelAbstract
The permissible load on a compressible rod is determined on the basis of the following conditions elastic character of its operation. In the case under consideration, the loss of performance of the rod can be caused by longitudinal compressive forces, which correspond to both homogeneous compression stresses and bending deformations, whose occurrence is associated with the loss of stability of the rod. The dangerous level of these forces depends on the flexibility of the rod, and the conditions for their limitation can be constructed by focusing on the yield strength of the material and the critical load of loss of stability. The presence of initial imperfections of the rod and imperfections of its loading conditions make it necessary to reduce the level of working loads due to the possibility of developing an unacceptable level of bending deformations. This is especially true for rods with high flexibility. The paper deals with the question of the magnitude of the longitudinal load causing the rod material to leave the elastic stage of operation under several types of geometrical imperfections related to the nature of the rod installation on the supports (three schemes – with fixed eccentricity, two schemes – with initial perdition, one scheme – eccentricity depending on the deflection). The problems are posed in a static formulation, large displacements and subcritical deformations of the rod are not considered. The paper is illustrated with graphs and tables in which, for square and circular bars, depending on the level of initial imperfections in the system, data are given on the parameters of the load causing inelastic deformation of the material and the corresponding values of the maximum deflection and the angle of rotation of the support section. The above results and their analysis show that the determination of the allowable load can be based on the linearized approach used in the technical theory of rod bending, which significantly facilitates the solution of the question.
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