scholarly journals INFLUENCE OF CREEP CONCRETE ON SPACE STABILITY THIN-WALLED DOME COVERINGS

2021 ◽  
Vol 1 (24) ◽  
Author(s):  
Ekaterina Prokshits ◽  
Sergey Gridnev ◽  
Olga Sotnikova ◽  
Iana Zolotukhina
Keyword(s):  
Theory Of Elasticity ◽  
Deformation Condition ◽  
Software Systems ◽  
Geometrical Parameters ◽  
Loss Of Stability ◽  
Construction Mechanics ◽  
Body Construction ◽  
Calculation Results ◽  
Load Action ◽  
Thin Walled

The task was set, due to the capabilities of modern software systems, to assess the effect of the increase in inelastic deformations under prolonged load action on the loss of stability of thin-walled dome coverings. The study of the dependences of the forms of the loss of stability of dome covering from creep concrete that will help further with optimization calculations when determining of the most influencing parameters of designs. Calculation results of thin-walled concrete dome roof of circular outline under the influence of operational loadings with use of two modern program complexes are given in article. It is investigated intense and deformation condition of dome coverings as a part of construction from position of forecasting of possible forms of loss of stability, with use of opportunities of the final and element «MidasCivil» computer system. In work provisions of the theory of elasticity, mechanics of deformation of solid body, construction mechanics and also methods of mathematical modeling based on application of finite element method are used. The received results give the chance to rationally select geometrical parameters and material of design and also to set structural strength safety factors at the solution of problems of stability of different covers taking into account possible creep of material.

scholarly journals Fem and Experimental Analysis of Thin-Walled Composite Elements Under Compression

2017 ◽  
Vol 22 (2) ◽  
pp. 393-402 ◽  
Author(s):  
P. Różyło ◽  
P. Wysmulski ◽  
K. Falkowicz
Keyword(s):  
Numerical Analysis ◽  
Cross Section ◽  
Numerical Models ◽  
Fem Analysis ◽  
Geometrical Parameters ◽  
Loss Of Stability ◽  
Composite Columns ◽  
Thin Walled Structures ◽  
Operating Stability ◽  
Thin Walled

Abstract Thin-walled steel elements in the form of openwork columns with variable geometrical parameters of holes were studied. The samples of thin-walled composite columns were modelled numerically. They were subjected to axial compression to examine their behavior in the critical and post-critical state. The numerical models were articulately supported on the upper and lower edges of the cross-section of the profiles. The numerical analysis was conducted only with respect to the non-linear stability of the structure. The FEM analysis was performed until the material achieved its yield stress. This was done to force the loss of stability by the structures. The numerical analysis was performed using the ABAQUS® software. The numerical analysis was performed only for the elastic range to ensure the operating stability of the tested thin-walled structures.

scholarly journals NUMERICAL STUDIES OF THE INFLUENCE OF THE PARAMETERS OF THIN-SHELL DOME STRUCTURE ON THEIR OPTIMIZATION FROM THE POSITION OF SPATIAL STABILITY

2021 ◽  
pp. 6-18
Author(s):  
S. Yu. Gridnev ◽  
O. A. Sotnikova ◽  
E. E. Prokshits
Keyword(s):  
Finite Element ◽  
Theory Of Elasticity ◽  
Topological Optimization ◽  
Design System ◽  
Sound Design ◽  
Construction Design ◽  
Construction Mechanics ◽  
Dome Structure ◽  
Deformation Mechanics ◽  
Thin Walled

Statement of the problem. The task was to evaluate the influence of the parameters of thin-walled dome coatings using the capabilities of modern software complexes. The method of optimization of dome covering structures with selection of criteria and parameters of the task has been improved. Results. The article presents the results of refinement and testing of the methodology for addressing the problem of optimizing dome structures with the choice of criteria and parameters of the optimization problem using the capabilities of the Topological Optimization module of the finite-element computational complex MidasCivil. The objective function was considered dependent on the thickness of the dome, the modulus of elasticity of the Poisson coefficient of the material. The study employs the positions of the theory of elasticity, solid body deformation mechanics, construction mechanics, as well as mathematical modeling methods based on the use of the finite element method employing modern licensed finite-element computing complexes Midas Civil and the Ing + architectural and construction design system of the calculation module MicroFe. Conclusions. Using the methods of optimal (in particular, geometric) design, the most affecting parameters of thin-walled dome coatings and their combinations were identified. This will allow us to design the most rational, economical and architectural-expressive dome structures as well as to make sound design decisions.

NUMERICAL STUDIES OF THE INFLUENCE OF THE PARAMETERS OF THIN-SHELL DOME STRUCTURE ON THEIR OPTIMIZATION FROM THE POSITION OF SPATIAL STABILITY

2020 ◽  
pp. 11-21
Author(s):  
С. Ю. Гриднев ◽  
О. А. Сотникова ◽  
Е. Е. Прокшиц
Keyword(s):  
Finite Element ◽  
Theory Of Elasticity ◽  
Topological Optimization ◽  
Design System ◽  
Sound Design ◽  
Construction Design ◽  
Construction Mechanics ◽  
Dome Structure ◽  
Deformation Mechanics ◽  
Thin Walled

Постановка задачи. Необходимо оценить влияние параметров тонкостенных купольных покрытий с использованием возможностей современных программных комплексов. Также требуется усовершенствовать методику оптимизации конструкций купольного покрытия с выбором критериев и параметров задачи. Результаты. Приведены результаты уточнения и апробации методики решения задачи оптимизации купольных конструкций с выбором критерия и параметров задачи оптимизации с использованием возможностей модуля «Топологическая оптимизация» конечно-элементного вычислительного комплекса «MidasCivil». Целевую функцию считали зависимой от толщины купола, модуля упругости коэффициента Пуассона материала. Использованы положения теории упругости, механики деформирования твердого тела, строительной механики, а также методы математического моделирования, основанные на применении метода конечных элементов с использованием современных лицензированных конечно-элементных вычислительных комплексов «MidasCivil» и системы сквозного архитектурно-строительного проектирования Ing+ расчетного модуля MicroFe. Выводы. Использование методов оптимального (в частности, геометрического) проектирования выявляет наиболее влияющие параметры тонкостенных купольных покрытий и их комбинации. Это позволит создавать рациональные, экономичные и архитектурно-выразительные купольные конструкции, а также принимать обоснованные проектные решения. Statement of the problem. The task was to evaluate the influence of the parameters of thin-walled dome coatings using the capabilities of modern software complexes. The method of optimization of dome covering structures with selection of criteria and parameters of the task has been improved. Results. The article presents the results of refinement and testing of the methodology for addressing the problem of optimizing dome structures with the choice of criteria and parameters of the optimization problem using the capabilities of the Topological Optimization module of the finite-element computational complex "MidasCivil." The objective function was considered dependent on the thickness of the dome, the modulus of elasticity of the Poisson coefficient of the material. The study employs the positions of the theory of elasticity, solid body deformation mechanics, construction mechanics, as well as mathematical modeling methods based on the use of the finite element method employing modern licensed finite-element computing complexes "MidasCivil" and the Ing + architectural and construction design system of the calculation module MicroFe. Conclusions. Using the methods of optimal (in particular, geometric) design, the most affecting parameters of thin-walled dome coatings and their combinations were identified. This will allow one to design the most rational, economical and architectural-expressive dome structures as well as to make sound design decisions.

scholarly journals A Hydrodynamic Methodology And CFD Analysis For Performance Prediction Of Stepped Planing Hulls

2015 ◽  
Vol 22 (2) ◽  
pp. 23-31 ◽  
Author(s):  
Hassan Ghassemi ◽  
Mojtaba Kamarlouei ◽  
Sajad Taj Golah Veysi
Keyword(s):  
High Speed ◽  
Hydrodynamic Performance ◽  
Hydrodynamic Characteristics ◽  
Geometrical Parameters ◽  
Cfd Analysis ◽  
Analysis Model ◽  
Marine Coatings ◽  
Resistance Reduction ◽  
Calculation Results ◽  
Fruitful Research

AbstractNowadays all efforts in planing hull research are focused on resistance reduction for achieving the highest speed in fast planing crafts. Furthermore, many fruitful research projects have been carried out on marine coatings, planing equipment, and optimization of propeller and hull form, which revolutionized industry of high - speed crafts and made them an efficient survival vehicle in coastal areas and rivers. In this paper the hydrodynamic performance of planing hulls are investigated by means of a modified Savitsky model for both non-stepped and stepped bodies. Meanwhile, in order to meet this goal reasonably, effective geometrical parameters of planing hull are investigated and then operational hydrodynamic characteristics of the craft are predicted by using a computational program. Finally, the calculation results are verified by means of a CFD-analysis model.

Experimental-numerical test of open section composite columns stability subjected to axial compression

2017 ◽  
Vol 84 (2) ◽  
pp. 58-64 ◽  
Author(s):  
P. Różyło
Keyword(s):  
Axial Compression ◽  
Cross Section ◽  
Critical State ◽  
Critical Loads ◽  
Composite Structures ◽  
Load Capacity ◽  
Numerical Test ◽  
Approximation Methods ◽  
Loss Of Stability ◽  
Thin Walled

Purpose: The aim of the work was to analyse the critical state of thin-walled composite profiles with top-hat cross section under axial compression. Design/methodology/approach: The purpose of the work was achieved by using known approximation methods in experimental and finite element methods for numerical simulations. The scope of work included an analysis of the behavior of thin-walled composite structures in critical state with respect to numerical studies verified experimentally. Findings: In the presented work were determined the values of critical loads related to the loss of stability of the structures by using well-known approximation methods and computer simulations (FEM analysis). Research limitations/implications: The research presented in the paper is about the potential possibility of determining the values of critical loads equivalent to loss of stability of thin-walled composite structures and the future possibility of analyzing limit states related to loss of load capacity. Practical implications: The practical approach in the actual application of the described specimen and methodology of study is related to the necessity of carrying out of strength analyzes, allowing for a precise assessment of the loads upon which the loss of stability (bifurcation) occurs. Originality/value: The originality of the research is closely associated with used the thinwalled composite profile with top-hat cross-section, which is commonly used in the fuselage of passenger airplane. The methodology of simultaneous confrontation of the obtained results of critical loads by using approximation methods and using the linear eigenvalue solution in numerical analysis demonstrates the originality of the research character. Presented results and the methodology are intended for researchers, who are concerned with the topic of loss of stability of thin-walled composite structures.

THE MIXING OF A JET OF CARBON DIOXIDE FROM SMASHING SUBSONIC FLOW

2018 ◽  
Vol 8 (2) ◽  
pp. 142-145
Author(s):  
Olga A. BALANDINA
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Numerical Calculation ◽  
Temperature Distribution ◽  
Subsonic Flow ◽  
Gas Jet ◽  
Geometrical Parameters ◽  
Aspect Ratios ◽  
Calculation Results ◽  
Jet Blowing

Presents the results of a numerical calculation of the interaction of the jet of carbon dioxide from smashing subsonic air fl ow. Were identifi ed and analyzed pressure values, the trajectories of the jet, the velocity profi les at small blowing intensities. The comparison of calculation results with experimental data of other authors. The obtained curves of the temperature distribution for carrying air fl ow and the jet issued from a slit-like holes with aspect ratios 1:2; 1:3; 1:4. Analysis of the results showed that the geometrical parameters of the jet blowing holes does not signifi cantly aff ect the temperature distribution in the region behind the jet. The research results can be used in the design of the jet bodies of the gas burners of boilers. Will conduct further modeling to enhance the process of formation of the gas-air mixture in the gas jet type burners.

scholarly journals Higher-Order Hierarchical Models for the Free Vibration Analysis of Thin-Walled Beams

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
G. Giunta ◽  
S. Belouettar
Keyword(s):  
Free Vibration ◽  
Cross Section ◽  
Vibration Analysis ◽  
Three Dimensional ◽  
Free Vibration Analysis ◽  
Approximation Order ◽  
Higher Order ◽  
Geometrical Parameters ◽  
Thin Walled ◽  
Three Dimensional Finite Element

This paper addresses a free vibration analysis of thin-walled isotropic beams via higher-order refined theories. The unknown kinematic variables are approximated along the beam cross section as aN-order polynomial expansion, whereNis a free parameter of the formulation. The governing equations are derived via the dynamic version of the Principle of Virtual Displacements and are written in a unified form in terms of a “fundamental nucleus.” This latter does not depend upon order of expansion of the theory over the cross section. Analyses are carried out through a closed form, Navier-type solution. Simply supported, slender, and short beams are investigated. Besides “classical” modes (such as bending and torsion), several higher modes are investigated. Results are assessed toward three-dimensional finite element solutions. The numerical investigation shows that the proposed Unified Formulation yields accurate results as long as the appropriate approximation order is considered. The accuracy of the solution depends upon the geometrical parameters of the beam.

scholarly journals Ensuring the reliability of the results of computer modeling of the behavior of bridge structures

2019 ◽  
Vol 6 (3) ◽  
Author(s):  
Azamat Adylov ◽  
Ilya Ovchinnikov ◽  
Igor Ovchinnikov ◽  
Boris Mandrik-Kotov
Keyword(s):  
Comparative Analysis ◽  
Nonlinear Behavior ◽  
Software Systems ◽  
Bridge Structure ◽  
Software Packages ◽  
Flat Design ◽  
Bridge Structures ◽  
Calculation Results ◽  
Margin Of Safety ◽  
Calculation Analysis

It is noted that structural mechanics is developing in the direction of improving design schemes, allowing more correctly assess the stress-strain state of structures. One of the topical areas of improvement is the consideration of nonlinear behavior and spatial work of structures. Constructive and genetic nonlinearities are added to the geometric and physical. Attention is drawn to the problem of checking the correctness of design decisions, which are not always based on existing standards, but are justified by calculations of more correct, but also more complex calculation schemes, performed using powerful software systems. To solve this problem, the Glavgosexpertiza recommended making calculations for at least two certified, independently developed and tested in practice software systems, and conducting a comparative analysis of the results. The question that arose about which software systems to use, it is proposed to solve with the help of MIDAS/CIVIL (South Korea) and SOFISTIK (Germany) complexes that have proven themselves quite well in bridge organizations. The article provides a comparative analysis of the MIDAS/CIVIL and SOFISTIK software packages using the spatial calculation of a bridge structure as an example, and the results are also compared with the calculation using the standard methodology. For analysis, the span structure of the railway bridge was adopted, consisting of two main split trusses with a bottom ride, reinforced with longitudinal and transverse beams in the level of movement of the railway load, longitudinal and transverse ties combining the upper and lower truss belts. The main trusses of the diagonal system are reinforced with vertical struts and suspensions. In general, analysis of the calculation results shows that both software systems give fairly close values of the calculated values of forces and stresses, and the differences for individual elements do not exceed 13.90 %. The normative calculation method provides mainly overestimated in comparison with SOFISTIK PC results, and the excess can reach 53.73 % for longitudinal forces and 49.71 % for normal stresses. This difference is a consequence of the use of a flat design scheme in the regulatory methodology, which leads to an increase in the level of the acting longitudinal forces, transverse forces and bending moments. That is, the normative calculation for a number of elements of a bridge structure is, as it were, a margin of safety. In conclusion, the requirements are formulated for specialists involved in the calculation analysis and examination of project documentation.

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