DURABILITY OF A RADAR PROTECTIVE DOME UNDER CONDITIONS OF DISSIPATIVE DEFORMATION

Abstract

The goals and objectives of research on creep and long-term strength of various metals are considered, their relevance is shown. The model of thin-walled elements under short-term and long-term loading and the calculation method are described, which allows determining the bearing capacity and long-term strength of thin-walled structures. The proposed model is compared with experimental studies in the "loading-unloading" mode and during long-term deformation. An example of calculations of a radar protective structure is given and recommendations are given for its rational outline. With proper operation, protective structures can serve for a long time without reducing the bearing capacity. With design errors, creep deformations can significantly increase over time and reach critical values during the operation of the structure. The properties and features of long-term deformation of structural elements under complex loading conditions are considered. During operation, microcracks and initial voids appear before any loads are applied. Brittle or plastic failure, which occurs as a result of the growth of residual deformations, strongly depends on the nature of the load. The last stage of material operation is the stage of destruction, which is manifested by macroscopic cracks. At the same time, the stress required for further growth of deformations decreases, the specific volume increases, and the final destruction of the integrity of the material occurs when the existing microcracks connect, forming a gap on the surface through the entire body. At the same time, the materials have slow deformations, which determine its long-term mechanical behavior and durability of structures. Long-term operation of protective structures, in particular, corresponding models of plates and shells, require adequate models that can confirm the reliability of their operation during the design period. In particular, finite element models, as the most universal at present. Creep models must take into account several important phenomena that significantly affect the behavior of structures during long-term operation, such as nonlinearity, anisotropy and thermal effects. Analysis of experimental results of creep of thin-walled structural elements given in the scientific literature allows us to describe the corresponding equations of state.