Yemelyanova T. Stress-strain state and bearing capacity of three-layer shells

The object of research - the process of nonlinear deformation and the phenomena of stabilities loss and free vibrations of three-layer shell constructions of a symmetrical structure with a light transversally isotropic aggregate, supported by ribs of stiffness in the longitudinal and transverse directions; goal - the improvement of calculation method and the development of research algorithms of the stability and free vibrations of three-layer shell constructions with a lightweight transversally isotropic aggregate which is supported by the longitudinal and transverse ribs, taking into account the action of longitudinal forces in the median planes of the outer layers and the ribs; methods - the retrospective generalization of scientific achievements of domestic and foreign scientists in studying the stability and free vibrations of the reinforced three-layer shell; the development of the research method of nonlinear-deformed state, stability and free vibrations of three-layer shell based on use of the variational principle of Ostrogradsky-Hamilton, an effective variant of the finite difference method, and the use of dynamic stability criteria in the equations of motion; results – the new calculation methods were built and algorithms for studying the stability and free vibrations of three-layer reinforced shells were developed, the frequencies and forms of free vibrations, the critical loading of reinforced three-layer shells and the quantitative dependences of the parameters of loss of stability and free vibrations depending on the physical and mechanical properties of the materials, geometric dimensions, curvature parameter and aggregate hardness parameter; the computer programs for determining the first frequencies of free oscillations, the critical force parameter and the stiffness parameter of the reinforced three-layer shell were developed; introduced - to educational process of OSABA at the training for masters in disciplines "Theory of shells" and "CADD / CAE automation design systems", as well as in the design practice of the ECOSTROY ECC (Odesa).