Nikalay Berkov

Разработана прикладная методика анализа соединений пересекающихся оболочек, основанная на теории оболочек, методе конечных элементов и теории пластического течения. Получен рациональный вычислительный алгоритм решения задач пересекающихся оболочек, учитывающий особенности напряжённого состояния оболочек в области пересечения. Выполнен расчётный анализ соединения полусферического днища с радиальным патрубком при действии внутреннего давления. Показано влияние анизотропии свойств композиционных волокнистых материалов на максимальные напряжения в пересекающихся композитных оболочках. Численное моделирование осуществлено методом конечных элементов в упругой и упругопластической постановке, расчёт проведен по авторской программе...

The objective of this paper is the further investigation of the shell intersection problem. The pad reinforced nozzle connections of the cylindrical vessel under internal and external loads are investigated using elastic–plastic analysis and the stress analysis in intersecting shells (SAIS) special-purpose computer program. The method for determining the plastic limit load based on the maximum criterion of the rate of the change of the relative plastic work and program module LOAD_PL for its realization are presented. The results of comparisons with the twice elastic-slope (TES) method were considered for determining the plastic limit load using known experimental data for models of a pad reinforced cylindrical vessel with a radial nozzle under a transverse force. The results of a parametric study of unreinforced and pad reinforced vessel models with a nozzle under internal pressure, in-plane moment, and out-plane moment loadings are discussed.

In this research, a new criterion for determining the plastic limit load in shell intersections using elastic-plastic finite element analysis is presented. Using the proposed maximum criterion of the rate of the change of the relative plastic work (PW), a numerical procedure is described to define the plastic pressure. Also, a specific plastic work criterion is presented using a local deformation parameter. Results of comparisons with different criteria were considered for experimental models of cylindrical vessels with radial and nonradial (lateral) nozzles. A parametric study of the radial intersections of cylindrical shells under the internal pressure loading was performed to examine the influence of the diameter ratio on the plastic limit pressure on the basis of the proposed criteria.