Block Based Finite Element Model for Layer Analysis of Stress Strain State of Three-Layered Shells with Irregular Structure

Ablock based finite element approach is proposed for layer-by-layer analysis of the stress strain state (SSS) of three-layer shells with an irregular structure. The shell aggregate can be modeled by the required number of finite elements over its thickness, which allows to take into account the change in the geometric and physico-mechanical properties of the material and the SSS parameters in all three coordinates to which the shell is related. According to the developed algorithm for constructing the finite elements (FE) of the aggregate, the inner and outer surfaces of the shell are accepted as datum surfaces and in the aggregate elements joined to the bearing layers, the same number of nodes is accepted as in the elements of the bearing layers. The same generalized displacements and approximations as for the elements of the bearing layers are taken as the nodal unknowns and the approximating functions of the aggregate, which allows to avoid errors caused by the breakdown of the generalized displacements on the interfaces between the layers. The algorithm for constructing a block-based finite element model for the layer-by-layer SSS analysis is considered using the example of irregular three-layer conical shells with moment-carrying layers and three-dimensional aggregate.