Abstract

The problem of dynamic deformation of a three-layer cylindrical shell under non-stationary loads in the case of rigid clamping of the shell ends is considered. The article presents the results of assessing the stress-strain state of a three-layer cylindrical shell, taking into account its structural feature, the ratio of the sheathing thickness and the physical and mechanical characteristics of a one-piece polymer filler. Calculations were performed by software complex Nastran. The values of displacements and stresses were calculated by the algorithm of direct transient dynamic process. The step duration of the time interval was 0.0000025 s, and the total number of steps was 200. The choice of the type of three-dimensional finite element was due to obtaining more detailed and accurate calculation results. The finite element model included 19000 three-dimensional finite elements and numbered 20800 nodes.
 The influence of geometrical parameters of shell layers with different physical and mechanical properties of one-piece filler on the stress-strain state under axisymmetric internal impulse load is investigated. Numerical results on the dynamics of the three-layer structure, obtained by the finite element method, allow to characterize the stress-strain state of the three-layer elastic structure of the cylindrical type at any time in the studied time interval. Optimization of the shell design is recommended. Changing the ratio of the thickness of the internal and external shells of the shell significantly affects the stress-strain state of the shell and its performance. Increasing the thickness of the internal layer of the shell significantly contributes to the increase of the latter. Comparison of the given results with materials of other similar researches and positions, testify to objectivity of the made approach.

Highlights

  • Problem statement Over the last years, the amount of the layered shells used in different engineering and production areas has considerably increased

  • Based on the analysis performed, the solution methods for this issue is basically focused on ensuring such conditions at which the maximal stress-strain state values of the shell would not exceed the specified admissible values

  • Additional efforts facilitating the optimization of the structures’ design and engineering solutions are required: determination of the rational balance of the structural elements’ thicknesses, the appropriate selection of the related structural materials etc. Efficiency effect of these efforts has been tested on the three-layer cylindrical shell under the conditions of rigid clamping of the shell ends

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Summary

Introduction

Problem statement Over the last years, the amount of the layered shells used in different engineering and production areas has considerably increased. Additional efforts facilitating the optimization of the structures’ design and engineering solutions are required: determination of the rational balance of the structural elements’ thicknesses, the appropriate selection of the related structural materials etc Efficiency effect of these efforts has been tested on the three-layer cylindrical shell under the conditions of rigid clamping of the shell ends. The shell’s stress-strain state indexes have been investigated provided the following proportions of the shell’s inner and outer sheathing thicknesses: h1/h3= 1, h1/h3= 2, h3/h1= 2 (Table 1) and the ratios of physical and mechanical characteristics of the inner base layer and the integral filling material Е1/Е2 = 500 and Е1/Е2 = 50. The stress-strain state indicators were calculated - the values of the displacements and stresses of the shell’s bearing layers. The finite element model (Fig. 3) included 19000 three-dimensional solid finite elements and 20800 nodes

Analysis of investigation results
Conclusions
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