A research on the stress-strain behaviour of structures made of filled shells

Introduction. The study of the stress-strain state of structures, made of filled shells, remains relevant in terms of interaction between principal structural elements (the shell, the filler, the bed), identification of the optimal combination of shell/filler characteristics, and conditions of their contact. The article addresses the findings of the research on a structural model of a thin cylindrical shell with a filler. Materials and methods. The problem of determining an effective ratio of basic dimensions of a structure is solved in the context of the maximally uniform distribution of forces in a shell with regard for the accepted constraints concerning the conditions of loading, fixing, and describing interaction between the model elements. In addition, the ratio of indicators of mechanical properties of the filler material and the shell is taken into account. The efficiency criterion is determined as a result of evaluating the stress state of a structure, at which forces inside the shell are distributed most evenly and the values of the radial forces are close to the forces directed along the generatrix of a shell. Results. The range of the effective ratio of the main dimensions of a shell is identified with regard for the ratio of the values of the indicator of the stress-strain behaviour of the shell and the filler, which is identified for larger groups of the internal filler, distinguished by the value of indicators of deformation characteristics. The co-authors have identified the ranges of ratios of geometric, rigidity and mechanical parameters of the system, that allow the structure to be attributed to the category of filled shells whose analysis can be performed with the help of applicable provisions of computational modeling. Conclusions. The results of the study allow for the selection of structural parameters based on the pre-set conditions and the criterion of uniformity of distribution of forces in a shell. The study also enables to identify the ratios of the above geometric, rigidity and mechanical parameters at which the structure should be attributed to the category of filled shells or “shells that have a filler” under the pre-set design conditions.