Three-dimensional program for calculating the stress-strain state of shell structures with a complicated spatial geometry

Atomic Energy ◽  
1996 ◽  
Vol 80 (2) ◽  
pp. 84-89 ◽  
Author(s):  
L. V. Sergeeva
2018 ◽  
Vol 243 ◽  
pp. 00021
Author(s):  
Pavel Pisarev ◽  
Aleksandr Anoshkin ◽  
Vladislav Ashihmin

In this research we developed a technique for calculating the stress-strain state of a model construction from a thermoplastic composite material with an embedded piezoactuator. Numerical simulations of the model construction stress-strain state with different arrangement of piezoactuators: upper and middle,-were performed. Numerical simulations were carried out in a three-dimensional setting taking into account the complete technological scheme of laying and anisotropy of the properties of reinforcing layers. The results of numerical experiments revealed the areas of maximum stress. Recommendations for the MFC’s embedding into composite materials were formulated.


Author(s):  
S Ponomarev ◽  
A Zhukov ◽  
A Belkov ◽  
V Ponomarev ◽  
S Belov ◽  
...  

The article describes the finding of the qualitative differences in the formation of the stress-strain state of a disturbed rock massif on the example of interchamber pillars with various methods of accounting for the structural disturbance and different spatial geometry of the cracks. Three numerical models are created with different methods of accounting for the disturbances in the massif continuity: in the first model, the strength of the massif is described by the Hoek and Brown criterion; the second and the third models are rock massifs for which violations in the continuity are formed explicitly, using ready-made templates of the systems of cracks presented in the Phase2 software product. The results obtained for the different models illustrate the inaccuracies occurring in assessing the disturbance of rock massif using score criteria. Models with underrated strength properties of the rock inaccurately describe the real mechanisms of the fractured massif: the qualitative description is not consistent with the results of field observations and geological surveys of rocks in general.


2020 ◽  
pp. paper13-1-paper13-12
Author(s):  
Alexey Semenov ◽  
Iurii Zgoda

The paper describes a mathematical model of changes in the geometry of thin-shell structures for visualization of the analysis data on their stress-strain state (SSS). Based on this mathematical model, a visualization module for shell SSS visualization using VR and AR technologies was developed. The interactive visualization environment Unity 2019.3 and C# programming language were used. The interactive visualization module makes a 3D image of a shell structure and visualizes the SSS either through heat maps over the shell or through the changes in the shell geometry on the basis of the shell type, its geometric characteristics, and SSS analysis data (transferred to the visualization module by means of a JSON file). While working on the visualization module, the authors developed a system of components that makes it possible to visualize any 3D surface with coordinate axes (including numbers with a pitch determined automatically), visualize heat maps with a graduated scale, visualize a mesh over the graph to improve the perception of the surface deformations. The middle surface can also be deformed on the basis of SSS analysis data. This solution increases the efficiency of the work of specialists in civil engineering and architecture and can be used when training specialists in courses on thin-shell structures and procedural geometry.


Author(s):  
Viktor Gaidaichuk ◽  
Kostiantyn Kotenko

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.


Author(s):  
V.V. LEONTYEV

The method for analyzing of stress-strain state characteristics of unloaded riveted joints performed with OST 1 11781-74 rivets has been developed using Coupled Euler-Lagrange finite element approach implemented in the CAD / CAE system Abaqus. A comparative analysis of the stress-strain state characteristics of the examined riveted joint’s finite element models using the Lagrangian and the Coupled Lagrangian-Eulerian finite element approaches has been conducted. A three- dimensional finite element model based on the CLE method has been proposed for further study of fatigue strength and durability of the loaded riveted joints.


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