Layer-by-Layer Analysis of the Stress-Strain State of Three-Layer Shells with Cutouts

Abstract

The stress-strain state (SSS) of three-layer shells with cutouts has not been sufficiently studied, which is one of the reasons limiting their use in modern designs. Based on the block finite element approach, a refined model of the layer-by-layer analysis of the SSS of irregular three-layer shells is developed. The considered approach allows us to fairly accurately model the heterogeneity of the package of layers and the aggregate layer, the conditions for fixing the layers and the application of loads to them, to apply various models to study the bearing layers and the aggregate. Using approximations of the finite elements (FE) of the bearing layers, approximating functions of the displacements of the three-dimensional FE of the aggregate are constructed and based on them, a model is developed for the accurate calculation of the SSS, allowing to take into account the change in the characteristics of the material and the stress state, including the radial coordinate in the aggregate layer. The study of the stress-strain state in the layers of three-layer shells with cuts, including through-holes, was carried out in a refined formulation. A significant reduction and smoothing of the stresses of the edge effect in the layers of three-layer shells with non-through cutouts compared with through cut due to the redistribution of the load was revealed, since a significant part of it is taken over by layers with undisturbed continuity.