scholarly journals PECULIARITIES OF WORK OF PROFILE PRODUCTS FROM COMPOSITE MATERIALS IN BUILDING CONSTRUCTIONS LOCATED IN SEISMIC AREAS

2021 ◽  
pp. 19-25
Author(s):  
V. B. IHNATIEVA ◽  
M. I. HUD
Keyword(s):  
Composite Materials ◽  
Cross Sections ◽  
Mechanical Characteristics ◽  
Building Structures ◽  
Negative Consequences ◽  
Complex Profile ◽  
Literary Sources ◽  
Simple Tension ◽  
Bending Load ◽  
Load Carrying

Purpose. The aim of the article is to reveal during the analysis the peculiarities of the work of profile products from composite materials in building structures located in seismic areas. Methodology. The structure of fiber-reinforced composite materials is given and the role of each component is explained. It is noted that recently, in the construction industry for the manufacture of basic and additional structures, composite materials are used not only on the basis of epoxy resins reinforced with glass fiber, but also on the basis of carbon, organic and other fibrous fillers. The expediency of the application of products from composite materials in the construction is highlighted. Findings. The analysis of literary sources devoted to the work of products from composite materials of simple and complex cross-section in the building structures under the influence of simple (tension, compression, torsion) and complex types of loading was conducted. Distribution of stresses acting in cross-sections of complex profile rod elements made of composite materials under bending load is shown. Features of work of profile products from composite materials in building constructions are revealed. The reasons of decrease of load-carrying ability of complex profile products made of composite materials are determined. The existing methods of increasing mechanical characteristics of products from composite materials are given. Negative consequences and disadvantages of application of existing methods of increasing mechanical characteristics of products from composite materials are formulated. Originality. On the basis of the carried out analysis conclusions about necessity of refinement of existing methods of increase of mechanical characteristics of products from composite materials are made. Practical value. During the analysis features of work of profile products from composite materials in building constructions which are the basis for development of new ways of increasing mechanical characteristics of products from composite materials in building constructions and improvement of already existing ones are revealed.

Effective Elements of Building Structures from Pipe Concrete

2019 ◽  
Vol 945 ◽  
pp. 80-84
Author(s):  
O.E. Sysoev ◽  
A.Y. Dobryshkin ◽  
Ye.O. Sysoyev
Keyword(s):  
Cross Sections ◽  
High Strength Concrete ◽  
High Efficiency ◽  
High Strength ◽  
Strength Properties ◽  
Building Structures ◽  
Strength Concrete ◽  
Concrete Pipe ◽  
Bending Load ◽  
Concrete Elements

The article is devoted to the investigation of pipe-concrete prestressed structural elements with high efficiency. This is due to a more complete use of the strength properties of structural materials in the pipe-concrete beam. The article presents various methods for calculating pipe-concrete elements. The design of a concrete tube with a prestressed element using high-strength concrete is presented. The results of calculations of various designs are shown and the cross-sections of beams for perception of the same bending load are selected. A comparison is made between the consumption of beam materials of various designs. The effectiveness of the use of pipe-concrete elements for receiving bending loads made of high-strength concrete with prestressed reinforcement is shown in comparison with the construction of beams of traditional high-strength concrete, high-strength concrete pipe-concrete with no prestressing of reinforcement and metal beam, mass of the element, consumption of metal and concrete.

scholarly journals FORECASTING CHARACTERISTICS OF COMPOSITE STRENGTH ON THE BASIS OF PREFORMS IN ELEMENTS OF BUILDING STRUCTURES

2020 ◽  
Vol 6 (159) ◽  
pp. 2-9
Author(s):  
A. Kondratiev ◽  
O. Andrieiev
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Composite Structures ◽  
High Speed ◽  
Mechanical Characteristics ◽  
Unidirectional Composite ◽  
Test Material ◽  
Practical Implementation ◽  
Building Structures ◽  
Physical And Mechanical Characteristics

Currently, wicker composite structures for various purposes are widely used in many industries. The use of such preforms allows to provide the possibility of automation of production, high speed and efficiency of the process of manufacturing polymeric composite materials and structures based on them. Knowledge of their properties allows you to optimize the production of structures with the necessary parameters during design. In the article the model of composite material on the basis of wicker reinforcement was further developed. For the practical implementation of this model, it is sufficient to test material samples with three different angles between the harnesses, for example, ± 30º, ± 45º and ± 60º. A mathematical description of the model is given. The model made it possible to predict the physical and mechanical characteristics of the composite material when it is laid out on curved surfaces. At the same time some fictitious limits of durability of a composite are defined. This is due to the fact that each value of the angle between the harnesses corresponds to its physical and mechanical characteristics of the unidirectional composite material. In this case, the ultimate strength curves necessarily pass through the points corresponding to the experimental data. The article shows that the possible deviations of the strength limits in the range of angles between the harnesses will lie within the range of characteristics obtained by testing. The article shows that in the realized interval of angles between the harnesses, almost any polynomial criterion of strength will accurately describe the strength of the composite reinforced with a braided sleeve. The obtained parameters, in contrast to the existing ones, allow to predict the strength characteristics of the composite on the basis of braided sleeves depending on the positioning and location of the material on the forming surface. The obtained results are the basis for solving the problems of calculating the strength of building structures from composite materials based on wicker preforms.

Properties of Self-Compacting Cementitious Composite Materials Containing Cement Kiln Dust Powder

2020 ◽  
Vol 38 (6A) ◽  
pp. 879-886
Author(s):  
Ahmed S. Kadhim ◽  
Alaa A. Atiyah ◽  
Shakir A. Salih
Keyword(s):  
Composite Materials ◽  
Total Porosity ◽  
Cement Kiln Dust ◽  
Cement Kiln ◽  
Cementitious Composite ◽  
Cement Dust ◽  
Micro Cracks ◽  
Load Carrying ◽  
Sustainable Materials ◽  
Kiln Dust

This paper aims to investigate the influence of utilization micro cement kiln dust as a sustainable materials additive in order to reduce the voids and micro cracks in the cementitious mortar materials which cause a drastic reduction in the load carrying capacity of the element. Its therefore very important to decrease the pores and enhance the mechanical strength of the cementitious composite materials. In this article, the properties of self-compacting mortar containing micro cement dust additive was experimentally assessed. Micro cement dust powder was added to the self-compacting mortar in (1, 2, 3, 4 and 5 %) percentage by weight of cement to be used as cementitious sustainable materials. The experimental results indicated that the modification and enhancement of the workability of fresh mixture and the mechanical strengths of self-compacting mortar were increased as micro cement dust additives increases. Also; the water absorption and total porosity were decreased with increases of micro cement dust powder.

scholarly journals On the determination of the bending fatigue strength in and above the very high cycle fatigue regime of shot-peened gears

2021 ◽  
Author(s):  
D. Fuchs ◽  
S. Schurer ◽  
T. Tobie ◽  
K. Stahl
Keyword(s):  
Fatigue Strength ◽  
High Cycle Fatigue ◽  
Load Carrying Capacity ◽  
Cycle Fatigue ◽  
Bending Fatigue ◽  
Very High Cycle Fatigue ◽  
Bending Load ◽  
Load Carrying ◽  
Bending Fatigue Strength ◽  
Very High

AbstractDemands on modern gearboxes are constantly increasing, for example to comply with lightweight design goals or new CO2 thresholds. Normally, to increase performance requires making gearboxes and powertrains more robust. However, this increases the weight of a standard gearbox. The two trends therefore seem contradictory. To satisfy both of these goals, gears in gearboxes can be shot-peened to introduce high compressive residual stresses and improve their bending fatigue strength. To determine a gear’s tooth root bending fatigue strength, experiments are conducted up to a defined number of load cycles in the high cycle fatigue range. However, investigations of shot-peened gears have revealed tooth root fracture damage initiated at non-metallic inclusions in and above the very high cycle fatigue range. This means that a further reduction in bending load carrying capacity has to be expected at higher load cycles, something which is not covered under current standard testing conditions. The question is whether there is a significant decrease in the bending load carrying capacity and, also, if pulsating tests conducted at higher load cycles—or even tests on the FZG back-to-back test rig—are necessary to determine a proper endurance fatigue limit for shot-peened gears. This paper examines these questions.

scholarly journals Eigenproblem Versus the Load-Carrying Capacity of Hybrid Thin-Walled Columns with Open Cross-Sections in the Elastic Range

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3468
Author(s):  
Zbigniew Kolakowski ◽  
Andrzej Teter
Keyword(s):  
Cross Sections ◽  
Carrying Capacity ◽  
Ultimate Load ◽  
Equilibrium Path ◽  
Load Carrying Capacity ◽  
Nonlinear Buckling ◽  
Elastic Range ◽  
Load Carrying ◽  
Thin Walled ◽  
Ultimate Load Carrying Capacity

The phenomena that occur during compression of hybrid thin-walled columns with open cross-sections in the elastic range are discussed. Nonlinear buckling problems were solved within Koiter’s approximation theory. A multimodal approach was assumed to investigate an effect of symmetrical and anti-symmetrical buckling modes on the ultimate load-carrying capacity. Detailed simulations were carried out for freely supported columns with a C-section and a top-hat type section of medium lengths. The columns under analysis were made of two layers of isotropic materials characterized by various mechanical properties. The results attained were verified with the finite element method (FEM). The boundary conditions applied in the FEM allowed us to confirm the eigensolutions obtained within Koiter’s theory with very high accuracy. Nonlinear solutions comply within these two approaches for low and medium overloads. To trace the correctness of the solutions, the Riks algorithm, which allows for investigating unsteady paths, was used in the FEM. The results for the ultimate load-carrying capacity obtained within the FEM are higher than those attained with Koiter’s approximation method, but the leap takes place on the identical equilibrium path as the one determined from Koiter’s theory.

Analysis of Seismic Performance of RC Frames with Centrally Reinforced Columns

2013 ◽  
Vol 671-674 ◽  
pp. 1319-1323
Author(s):  
Zi Xue Lei ◽  
Yu Hang Han ◽  
San Sheng Dong ◽  
Jun Qing Guo
Keyword(s):  
Seismic Performance ◽  
Cross Sections ◽  
Carrying Capacity ◽  
Pushover Analysis ◽  
Seismic Load ◽  
Load Carrying Capacity ◽  
Rc Columns ◽  
Rc Column ◽  
Rc Frames ◽  
Load Carrying

A centrally reinforced column is a new type of RC columns, formed by providing a reinforcement skeleton at the central part of the cross section of an ordinary RC column. Tests have shown that as compared with an ordinary RC column, this type of columns has a higher load carrying capacity and ductility. From the pushover analysis of a frame composed of ordinary RC columns and one consisting of centrally reinforced columns, their seismic performance under seismic load of 9-degree intensity was studied according to Chinese code, including target displacements, story-level displacements, interstory drifts, appearance and development of plastic hinges. The results indicate that although the dimensions of cross sections of columns in the frame with centrally reinforced columns are smaller than those of the ordinary frame, the former still has a higher overall load carrying capacity and seismic performance than the latter.

Modeling the HSK Toolholder-Spindle Interface

2002 ◽  
Vol 124 (3) ◽  
pp. 734-744 ◽  
Author(s):  
Ihab M. Hanna ◽  
John S. Agapiou ◽  
David A. Stephenson
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
System Reliability ◽  
High Volume ◽  
Finite Element Models ◽  
Operational Experience ◽  
Bending Load ◽  
Load Carrying ◽  
Detailed Evaluation ◽  
Contact Pressures

The HSK toolholder-spindle connection was developed to overcome shortcomings of the 7/24 steep-taper interface, especially at higher speeds. However, the HSK system was standardized quickly, without detailed evaluation based on operational experience. Several issues concerning the reliability, maintainability, and safety of the interface have been raised within the international engineering community. This study was undertaken to analytically investigate factors which influence the performance and limitations of the HSK toolholder system. Finite Element Models were created to analyze the effects of varying toolholder and spindle taper geometry, axial spindle taper length, drawbar/clamping load, spindle speed, applied bending load, and applied torsional load on HSK toolholders. Outputs considered include taper-to-taper contact pressures, taper-to-taper clearances, minimum drawbar forces, interface stiffnesses, and stresses in the toolholder. Static deflections at the end of the holder predicted by the models agreed well with measured values. The results showed that the interface stiffness and load-carrying capability are significantly affected by taper mismatch and dimensional variations, and that stresses in the toolholder near the drive slots can be quite high, leading to potential fatigue issues for smaller toolholders subjected to frequent clamping-unclamping cycles (e.g., in high volume applications). The results can be used to specify minimum toolholder material properties for critical applications, as well as drawbar design and spindle/toolholder gaging guidelines to increase system reliability and maintainability.

scholarly journals Development of means for experimental identification of navigator attention in ergatic systems of maritime transport

2020 ◽  
Vol 97 (1) ◽  
pp. 58-69
Author(s):  
P.S. Nosov ◽  
◽  
I.V. Palamarchuk ◽  
S.M. Zinchenko ◽  
Ya.A. Nahrybelnyi ◽  
...  
Keyword(s):  
Maritime Transport ◽  
Negative Consequences ◽  
Experimental Identification ◽  
System A ◽  
Geometric Approximation ◽  
Literary Sources ◽  
Special Means ◽  
Software And Hardware ◽  
Port Areas ◽  
Critical Situations

The article discusses the issues of identification of models of analysis of the navigational situation by the navigator during the passage in narrow places and port areas; this is especially relevant in critical situations. As part of the research, an analysis of literary sources was carried out, which made it possible to characterize this direction as actual for the development of special means of an experimental nature. As the main goal, the article presents formal-logical approaches to the development of software and hardware means for determining the areas of attention of the navigator as a subject of an ergatic system. A mechanism was determined for the formation the indexes of the analytical activities of the navigator during assessing the situation, mathematical models, and means for clarifying the position of the navigator on the navigation bridge. A geometric approximation of indexes was proposed, the metric of which can significantly reduce the identification time of critical situations and prevent negative consequences. The carried experiments by using the certified navigation simulator Navi Trainer 5000 confirmed the effectiveness and practical value of the proposed approaches, which will greatly improve the retraining of marine crew.

scholarly journals The Influence of Composite Polymeric Materials Topology Over the Shearing Modulus Using Virtual Instruments

2018 ◽  
Vol 55 (4) ◽  
pp. 524-530
Author(s):  
Marinela Marinescu ◽  
Larisa Butu ◽  
Claudia Borda ◽  
Delicia Arsene ◽  
Mihai Butu
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Virtual Instrument ◽  
Mechanical Characteristics ◽  
Polymeric Materials ◽  
Mechanical Impedance ◽  
Impedance Analysis ◽  
Cross Linking ◽  
Labview Software ◽  
Different Temperatures

This study presents research regarding the calculation of the mechanical characteristics of composite polymeric materials. By using LabVIEW� software a virtual instrument was created used for monitoring in real time the process of cross-linking the composite polymeric materials. The experiments were realized based on composite materials containing epoxy/fiberglass resin of different topologies. By means of the virtual instrument and of a sensor created based on the mechanical impedance analysis, implanted in the composite material, it was determined the G shearing module of the composite material at different temperatures.

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