DESIGN AND ANALYSIS OF COMBINED PLANE STEEL GUYED TOWER-MAST

2009 ◽  
Vol 1 (4) ◽  
pp. 157-165 ◽  
Author(s):  
Algirdas Juozapaitis ◽  
Donatas Jatulis ◽  
Antanas Šapalas
Keyword(s):  
Structural Analysis ◽  
Cross Section ◽  
Economic Efficiency ◽  
Point Of View ◽  
Mixed System ◽  
Bending Moments ◽  
Combined System ◽  
Scientific Publications ◽  
Cross Sectional ◽  
Internal Forces

One of the most effective and widely used high-rise telecommunication structures are steel towers and guyed masts. The behaviour, analysis and application fields are exhaustively discussed in a number of scientific publications. The main advantages of tower structures are low building area, however, from the point of view of steel consumptions, such structures are not effective enough. For technical-economic efficiency not only the rational types of cross sections for typical mast elements are selected, but also various combined structural systems are developed and implemented. Flat tower-masts are also known. They are combined from a single plain truss supported out of its plane by guys. In this case, such mixed system is able to carry acting loads and actions in one direction like a tower and in other direction – like a mast. From a technicaleconomic point of view, such system stands in the intermediate position between the guyed mast and the tower. The major weakness of such framework is relatively great depth and the cross sectional area of the chords of the tower truss which is caused by the relatively high values of the bending moment in the chord acting in the plane of guys and the large buckling length of the chord out of truss plane. It must be stressed that wind action on the investigated structure directly depends on the dimensions of the chord cross section. This paper deals with the new combined plain tower-mast structure the chords of which out of plane are stiffened by and inserted between the guys connecting joints and the double-sided strut members. These members are pre-stressed to avoid compression induced by transverse loading. The analysis of the behavior of a separate strut system under transversal loading is performed and analytical expressions for determining internal forces and displacements in its members with and without pre-stressing are provided. The minimum values of the required pre-stressing in ties of the strut system are described. It is proved that a proper choice of the parameters of structural components gives a possibility of obtaining a favorable distribution of bending moments in the chord. On the basis of numerical experiments, a comparison between the results defined analytically and ones determined by the means of the Autodesk Robot Structural Analysis program is performed. The accuracy of the proposed analytical method is discussed. For defining the behaviour peculiarities of the new combined structural system and for estimating its technical-economic efficiency, the numerical experiment by the means of FEM program (Autodesk Robot Structural Analysis) was carried out. Analysis was performed using 98 meter high ordinary and new guyed tower-mast structures with guys fixed at four levels. The member sections of the analyzed structures designed according to the values of the defined acting internal forces are presented. It is estimated that using strut members helps in considerably reducing (about 4,8 times) the maximum values of bending moments in the chords of tower truss. It was estimated that depth between the chords in a new combined system was 2 times lesser than that in the ordinary tower – mast system. It is shown that in case of the same cross section and value of the pre-stressing force, the value of the vertical reaction of the new strutted tower-mast system on foundation was 1,65 time lesser than that in the ordinary system. Conclusions and recommendations are provided.

Methodological Approach to Assessing the Economic Efficiency of Digital Projects Applying Internet of Things Platforms

2021 ◽  
Vol 152 (6) ◽  
pp. 134-142
Author(s):  
Aleksandr Yu. Mishin ◽  
Keyword(s):  
Internet Of Things ◽  
Economic Efficiency ◽  
Methodological Approach ◽  
Objective Assessment ◽  
Cost Effective ◽  
Scientific Work ◽  
Point Of View ◽  
Scientific Publications ◽  
Economic Point ◽  
Iot Platforms

One of the key ones and most cost-effective technology from an economic point of view for the real sector is the Internet of Things (IoT) technology, which is usually provided in the form of Internet of Things (IoT) platforms, still does not have its own framework for assessing its economic efficiency. The author proposes a methodological approach based on a combination of classical methods of investment analysis and an architectural approach. From the information point of view the scientific work is based on cost-effectiveness studies of IoT projects, domestic and foreign scientific publications, IT cases and research on taxonomy of IoT platforms. The proposed approach may serve as the basis both for preparation of financial business cases and for facilitating the development of tools for objective assessment of the project initiatives attractiveness as part of implementation of the state digital development programs in Russia.

scholarly journals Determining internal forces in modular building elements under action wind load

2018 ◽  
Vol 196 ◽  
pp. 02010
Author(s):  
Viacheslav Shirokov ◽  
Alexey Soloviev ◽  
Tatiana Gordeeva
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cross Section ◽  
Dynamic Characteristics ◽  
Wind Load ◽  
Wind Loads ◽  
Bending Moments ◽  
The Finite Element Method ◽  
Calculation Results ◽  
Internal Forces

The research paper focuses on internal forces determination in the elements of modular buildings under wind load. It provides a methodology for determining dynamic characteristics of a building and for calculating wind loads. This method is based on the following assumptions: coupling of the modules elements is rigid; coupling of block-modules with foundations is hinged-fixed; connection of blocks to each other is hinged in angular points; the floor disk in its plane is not deformed. On the basis of these assumptions the authors derived approximate and refined equations for determining forces in modules elements under static and pulsation components of wind load. The equation of bending moments determination in the pillar bearing cross-section is obtained by approximation of the graph of moments variation, calculated for the spectrum of the ratio of the pillar stiffness and the floor beam in the range from 1/64 to 64. The paper further introduces the calculation results of forces based on the proposed methodology and on the finite element method. The calculations were done while taking different values of wind load and different number of storeys in a building (from 1 to 4 floors). The obtained results are similar, the error does not exceed 5%.

Calculation of State Transfer of Curved Bridge

2011 ◽  
Vol 243-249 ◽  
pp. 1701-1706 ◽  
Author(s):  
Jing Jing Xi ◽  
Qing Ning Li ◽  
Tian Li Wang
Keyword(s):  
Differential Equation ◽  
Structural Analysis ◽  
Cross Section ◽  
Transfer Matrix Method ◽  
Transfer Equation ◽  
Matrix Method ◽  
Curved Bridge ◽  
State Transfer ◽  
Torsional Coupling ◽  
Internal Forces

The field transfer matrixs and the point transfer matrixs can be established by the transfer matrix method, which can solve the internal forces and deformations problems of each cross-section, based on the solutions of deflection differential equation of the curved bridge. The bending-torsional coupling, horizontal bending and axial deformations should be considered into the structural analysis of the curved bridge, under the influence of curvature. To establish the general transfer equation requires the field transfer matrixs and the point transfer matrixs of the curved bridge in horizontal and vertical directions. The state vectors of each cross-section can be obtained depending on the general transfer equation.

Semicrystalline Structure and Mechanical Properties of Polyolefin-Based Materials

2012 ◽  
Vol 441 ◽  
pp. 713-716
Author(s):  
Mizue Kuriyagawa ◽  
Koh Hei Nitta
Keyword(s):  
Mechanical Properties ◽  
Cross Section ◽  
Draw Ratio ◽  
Structural Model ◽  
Point Of View ◽  
Cross Sectional ◽  
Molecular Weights ◽  
The Cross ◽  
Sectional Shape ◽  
Structural Point

The mechanical yielding and necking behaviors of metallocene-catalyzed high density polyethylenes were investigated from a structural point of view. In particular the natural draw ratio was investigated with different crosshead speeds, molecular weights, and the cross-section shapes of sample specimens. We proposed a structural model for explaining the necking formation in addition to the molecular weight and the cross-sectional shape dependences of the natural draw ratio.

Free Warping Analysis and Numerical Implementation

2016 ◽  
Vol 825 ◽  
pp. 141-148 ◽  
Author(s):  
Karel Mikeš ◽  
Milan Jirásek
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Laplace Equation ◽  
Solution Algorithm ◽  
Point Of View ◽  
Warping Function ◽  
Numerical Implementation ◽  
Finite Element Code ◽  
The Finite Element Method ◽  
Cross Sectional

This article deals with the mathematical description and numerical implementation of the free warping problem. The solution of the warping problem is given by a warping function obtained by solving the Laplace equation with a corresponding boundary condition. An analytical solution is available only for a limited number of specific cross-sectional shapes such as ellipse or rectangle. For the solution of a general cross section, the Laplace equation must be solved numerically by the finite element method. From a mathematical point of view, the free warping problem can be described in the same way as the heat transfer phenomena, but in the numerical implementation, there are several features specific to warping analysis.The solution algorithm has been implemented in the OOFEM open-source finite element code [1] and verification has been done on several examples with known analytical solutions.

scholarly journals A content analysis of articles published in recent decade in environmental health journals with an emphasis on air pollution

2019 ◽  
Author(s):  
Seyed Ali Sajjadi ◽  
Aram Tirgar ◽  
Zahra Aghalari
Keyword(s):  
Air Pollution ◽  
Environmental Health ◽  
Recent Decade ◽  
Cross Sectional Study ◽  
International Committee ◽  
Laboratory Method ◽  
Point Of View ◽  
Scientific Publications ◽  
Cross Sectional ◽  
World Association

Introduction: Air pollution is one of the environmental concerns of many countries, including Iran. One of the most common and effective ways to ex- plain the importance of this issue is to perform research and publish scientific articles. Therefore, this study aimed to monitor scientific publications on air pollution in the specialized environmental health journals of Iran within the last ten years. Materials and methods: This descriptive cross-sectional study was conduct- ed on all articles published in the field of air pollution in five specialized en- vironmental health journals within 10 years (2008-2017). Data were collected using a checklist in accordance with the research objectives. The variables  in the checklist were selected based on the recommended items for writing medical articles by the International Committee of Medical Journal Editors (ICMJE) and the World Association of Medical Editors (WAME). The ob- tained data was analyzed using descriptive statistics. Results: Reviewing 1276 articles in 102 issues of the 5 specialized environ- mental health journals showed that 11.6 % of articles were published in the field of air pollution. The trend in air pollution researches over the past de- cade was a slow and growing trend. Studying articles related to air pollution showed that the highest proportion of articles (45.3 %) in this field were relat- ed to measuring the organic matter. The analysis of the content of the articles showed that, from the research methodology point of view, most articles (24.3 %) were performed by laboratory method. Conclusion: Due to the widespread nature of air pollution issue in many cit- ies of Iran and other countries in recent years and its destructive effects on hu- man and other creatures, it is expected to focus and perform more researches on this issue. Hence, health policymakers should place the air pollution issue at a higher priority, and also it would be useful for researchers, especially graduate students, to focus on research in this area, drawing international co- operation.

scholarly journals THE ANALYSIS OF RECTANGULAR COLUMN PERFORMANCE TOWARDS STRUCTURAL REINFORCED CONCRATE ELEMENTS BEHAVIOR

2019 ◽  
Vol 3 (2) ◽  
pp. 123
Author(s):  
Celica Amira ◽  
Dwi Nurtanto ◽  
Nanin Meyfa Utami
Keyword(s):  
Structural Analysis ◽  
Cross Section ◽  
Axial Load ◽  
Building Structure ◽  
Sectional Area ◽  
Analysis Program ◽  
Cross Sectional ◽  
Interaction Diagram ◽  
Shear Loads ◽  
High Building

The column has a different cross-sectional capacity based on the direction of the X and Y moments based from the cross section. This research analyzes the performance of reinforced concrete by transformis the square column that already exists into a rectangular column with the function of the building is apartment. The result of this research was to find out performance of rectangular column on the behavior of high building structure. This Research analyzes two shapes of column rectangular and Square with the same area of concrete and reinforcement with all sides equal. Structure will be modeled by structural analysis program. Analyze using interaction diagram by structural analysis program. to find out the collapse of the column. The results of this Research indicates that axial load in any cross section has the same values, as long as the column has the same cross-sectional area and total of reinforcement area. Moment and shear loads with rectangular have a smaller Force on the strong axis X, while in weak axis Y have a greater Force. The displacement on the strong axis X with Square column have a smaller deviations of 10,81%, while on the weak axis Y have a greater deviations of 12,05%. Kolom memiliki kapasitas penampang yang berbeda berdasarkan arah momen X dan Y jika dilihat dari sisi penampangnya. Penelitian ini menganalisis kinerja struktur beton bertulang dengan merubah bentuk persegi sama sisi menjadi bentuk persegi panjang dengan fungsi bangunan sebagai apartemen. Tujuan penelitian ini untuk mengetahui kinerja kolom dengan bentuk persegi panjang terhadap perilaku struktur gedung seperti simpangan dan gaya dalam pada gedung dalam menerima beban gempa. Penelitian ini dilakukan dengan dua bentuk penampang, yaitu persegi sama sisi dan persegi panjang dengan luas penampang beton serta luas tulangan sama dengan tulangan merata. Struktur dimodelkan menggunakan program bantu struktur. Menganalisis kolom menggunakan diagram interaksi dengan program bantu struktur untuk mengetahui letak keruntuhan kolom. Hasil analisis menunjukkan gaya aksial dalam bentuk penampang apapun memiliki hasil yang sama, selama memiliki luas penampang kolom dan luas tulangan total yang sama. Gaya momen dan gaya geser kolom persegi panjang menghasilkan gaya yang lebih kecil pada sumbu kuat X, sedangkan pada sumbu lemah Y menghasilkan gaya yang lebih besar. Simpangan struktur antar lantai pada sumbu kuat X dengan penampang kolom persegi sama sisi menghasilkan simpangan yang lebih kecil 10,81%, sedangkan pada sumbu lemahnya menghasilkan simpangan lebih besar yaitu 12,05%.

Mass Determination by Direct Measurement of Electron Scattering

1975 ◽  
Vol 33 ◽  
pp. 240-241
Author(s):  
M. K. Lamvik ◽  
A. V. Crewe
Keyword(s):  
Cross Section ◽  
Electron Scattering ◽  
Mass Density ◽  
Variable Mass ◽  
Scattering Cross Section ◽  
Mass Determination ◽  
Number Density ◽  
Cross Sectional ◽  
Thin Slice ◽  
Scattering Cross

If a molecule or atom of material has molecular weight A, the number density of such units is given by n=Nρ/A, where N is Avogadro's number and ρ is the mass density of the material. The amount of scattering from each unit can be written by assigning an imaginary cross-sectional area σ to each unit. If the current I0 is incident on a thin slice of material of thickness z and the current I remains unscattered, then the scattering cross-section σ is defined by I=IOnσz. For a specimen that is not thin, the definition must be applied to each imaginary thin slice and the result I/I0 =exp(-nσz) is obtained by integrating over the whole thickness. It is useful to separate the variable mass-thickness w=ρz from the other factors to yield I/I0 =exp(-sw), where s=Nσ/A is the scattering cross-section per unit mass.

A tilting high temperature gas reaction chamber for the JEM 7A T.E.M.

1978 ◽  
Vol 36 (1) ◽  
pp. 70-71
Author(s):  
Brian L. Rhoades
Keyword(s):  
Cross Section ◽  
Reaction Chamber ◽  
Objective Lens ◽  
Reduced Cross Section ◽  
Cross Sectional ◽  
Structural Investigations ◽  
Transmission Electron ◽  
Dynamic Experiments ◽  
Successful Design ◽  
Thermocouple Junction

A gas reaction chamber has been designed and constructed for the JEM 7A transmission electron microscope which is based on a notably successful design by Hashimoto et. al. but which provides specimen tilting facilities of ± 15° aboutany axis in the plane of the specimen.It has been difficult to provide tilting facilities on environmental chambers for 100 kV microscopes owing to the fundamental lack of available space within the objective lens and the scope of structural investigations possible during dynamic experiments has been limited with previous specimen chambers not possessing this facility.A cross sectional diagram of the specimen chamber is shown in figure 1. The specimen is placed on a platinum ribbon which is mounted on a mica ring of the type shown in figure 2. The ribbon is heated by direct current, and a thermocouple junction spot welded to the section of the ribbon of reduced cross section enables temperature measurement at the point where localised heating occurs.

Microstructure of laser-irradiated, conducting Kapton polyimide

1995 ◽  
Vol 53 ◽  
pp. 502-503
Author(s):  
D. L. Callahan ◽  
Z. Ball ◽  
H. M. Phillips ◽  
R. Sauerbrey
Keyword(s):  
Electron Microscopy ◽  
Phase Transition ◽  
Transmission Electron Microscopy ◽  
Cross Section ◽  
Film Surface ◽  
Cross Sectional ◽  
General Utility ◽  
Transmission Electron ◽  
Considerable Debate ◽  
Potential Applications

Ultraviolet laser-irradiation can be used to induce an insulator-to-conductor phase transition on the surface of Kapton polyimide. Such structures have potential applications as resistors or conductors for VLSI applications as well as general utility electrodes. Although the percolative nature of the phase transformation has been well-established, there has been little definitive work on the mechanism or extent of transformation. In particular, there has been considerable debate about whether or not the transition is primarily photothermal in nature, as we propose, or photochemical. In this study, cross-sectional optical microscopy and transmission electron microscopy are utilized to characterize the nature of microstructural changes associated with the laser-induced pyrolysis of polyimide.Laser-modified polyimide samples initially 12 μm thick were prepared in cross-section by standard ultramicrotomy. Resulting contraction in parallel to the film surface has led to distortions in apparent magnification. The scale bars shown are calibrated for the direction normal to the film surface only.

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