The paper considers the results of modeling the cable system of the above-water cable-stayed transition of the main gas pipeline using a laboratory installation and computer modeling using finite element methods. The main characteristics of materials and structural elements used to create a computer and laboratory model are given. Various modes of tension of the cable system affecting the further operation of the model under consideration, allowing to determine the service life of the object, are studied. It is shown that with a slight weakening of the tension of one of the cables, in the cable system, the occurrence of stresses in the pipe body is observed, the magnitude of which, under certain conditions, greatly exceeds the operating values. A small imbalance of effort leads to a redistribution of effort and a distortion of the entire structure, which, under cyclic loads, can lead to a premature exit from the standing of the object in question.

Keywords: cable-stayed transition, effort, stress-strain state, cable system, finite element method, model, load, force.

"Prediction of carbon concentration profiles depending on the cementation parameters is possible using mathematical models, most of which show good results for austenite Fe-C, without affecting the influence of alloying substitution elements. The paper describes modeling using the finite element method of the diffusion saturation of the austenite of the Fe-C-Cr system with carbon during cementation using 15Cr steel as an example, taking into account the influence of temperature, and also provides practical confirmation of the model. For the numerical solution of the problem, the COMSOL Multiphysics program was used. It has been established that for the one-stage cementation mode, the applied model of carbon diffusion in undoped austenite is in good agreement with the experimental data for austenite of the Fe-C-Cr system of steel 15Cr. For a two-stage process, the calculation of carbon concentration in the surface layer has a slightly larger deviation from the experimental data than at a greater depth."

Keywords: carbon diffusion, COMSOL, final method, carburization, cementation, steel, diffusion, mass transfer, alloyed austenite, modeling, elements