scholarly journals Evaluation of the Warping Model for Analysis of Polystyrene Concrete Slabs with Profiled Steel Sheeting

2017 ◽  
Author(s):  
Volodymyr Cherednikov ◽  
Olena Voskobiinyk ◽  
Olexandra Cherednikova
Keyword(s):  
Mechanical Properties ◽  
Experimental Studies ◽  
Concrete Slabs ◽  
Strained State

In this article the possibility of applying the warping model offered by V. G. Piskunov, A. V. Goryk and V. N. Cherednikov for analyzing polystyrene concrete slabs with profiled steel sheeting is considered. The adequacy of the offered model was verified by comparing the experimental and calculated deflections of the slab. Test specimens of polystyrene concrete slabs with profiled steel sheeting (PCSPSS) were made for experimental studies and then mechanical properties of the slab components – the polystyrene concrete and the profiled steel sheeting – were determined. Then the behaviour of slabs under a load was studied. The calculation of the warping model of PCSPSS was done at the same time. The obtained results have proved the possibility of applying of the offered warping model for analysis of PCSPSS. It is proposed to use the considered model for further study of the stress-strained state of inhomogeneous slabs.

Methodology of studying the mechanical properties of composite materials (reinforced concrete)

2018 ◽  
Vol 84 (12) ◽  
pp. 61-67
Author(s):  
V. A. Eryshev
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Experimental Studies ◽  
Analytical Relationship ◽  
Hardened Concrete ◽  
Deformation Model ◽  
Joint Work ◽  
Concrete Shrinkage ◽  
Axial Tension ◽  
Tension And Compression

The mechanical properties of a complex composite material formed by steel and hardened concrete, are studied. A technique of operative quality control of new credible concrete and reinforcement, both in laboratory and field conditions is developed for determination of the strength and strain characteristics of materials, as well as cohesion forces determining their joint operation under load. The design of the mobile unit is presented. The unit provides a possibility of changing the direction of loading and testing the reinforced element of the given shape both for tension and compression. Moreover, the nomenclature of testing equipment and the number of molds for manufacturing concrete samples substantially decrease. Using the values of forcing resulting in concrete cracking when the joint work of concrete and reinforcement is disrupted the values of the inherent stresses and strains attributed to the concrete shrinkage are determined. An analytical relationship between the forces and deformations of the reinforced concrete sample with central reinforcement is derived for axial tension and compression, with allowance for strains and stresses in the reinforcement and concrete resulted from concrete shrinkage. The results of experimental studies are presented, including tension diagrams and diagrams of developing axial deformations with an increase in the load under the central loading of the reinforced elements. A methodology of accounting for stresses and deformations resulted from concrete shrinkage is developed. The applicability of the derived analytical relationships between stresses and deformations on the material diagrams to calculations of the reinforced concrete structures in the framework of the deformation model is estimated.

scholarly journals Structural and physical properties of 99 complex bulk chalcogenides crystals using first-principles calculations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sahib Hasan ◽  
Khagendra Baral ◽  
Neng Li ◽  
Wai-Yim Ching
Keyword(s):  
Mechanical Properties ◽  
Physical Properties ◽  
First Principles ◽  
Experimental Studies ◽  
First Principles Calculations ◽  
Chalcogenide Semiconductors ◽  
Optical And Mechanical Properties ◽  
Very Large Database ◽  
Unique Composition ◽  
Fundamental Physical

AbstractChalcogenide semiconductors and glasses have many applications in the civil and military fields, especially in relation to their electronic, optical and mechanical properties for energy conversion and in enviormental materials. However, they are much less systemically studied and their fundamental physical properties for a large class chalcogenide semiconductors are rather scattered and incomplete. Here, we present a detailed study using well defined first-principles calculations on the electronic structure, interatomic bonding, optical, and mechanical properties for 99 bulk chalcogenides including thirteen of these crytals which have never been calculated. Due to their unique composition and structures, these 99 bulk chalcogenides are divided into two main groups. The first group contains 54 quaternary crystals with the structure composition (A2BCQ4) (A = Ag, Cu; B = Zn, Cd, Hg, Mg, Sr, Ba; C = Si, Ge, Sn; Q = S, Se, Te), while the second group contains scattered ternary and quaternary chalcogenide crystals with a more diverse composition (AxByCzQn) (A = Ag, Cu, Ba, Cs, Li, Tl, K, Lu, Sr; B = Zn, Cd, Hg, Al, Ga, In, P, As, La, Lu, Pb, Cu, Ag; C = Si, Ge, Sn, As, Sb, Bi, Zr, Hf, Ga, In; Q = S, Se, Te; $$\hbox {x} = 1$$ x = 1 , 2, 3; $$\hbox {y} = 0$$ y = 0 , 1, 2, 5; $$\hbox {z} = 0$$ z = 0 , 1, 2 and $$\hbox {n} = 3$$ n = 3 , 4, 5, 6, 9). Moreover, the total bond order density (TBOD) is used as a single quantum mechanical metric to characterize the internal cohesion of these crystals enabling us to correlate them with the calculated properties, especially their mechanical properties. This work provides a very large database for bulk chalcogenides crucial for the future theoretical and experimental studies, opening opportunities for study the properties and potential application of a wide variety of chalcogenides.

Impact of the Limestone Powder on the Properties of Cement Paste and Mortar

2012 ◽  
Vol 174-177 ◽  
pp. 236-240
Author(s):  
Jing Zhang ◽  
Zhu Li
Keyword(s):  
Mechanical Properties ◽  
Cement Paste ◽  
Experimental Studies ◽  
Water Requirement ◽  
Limestone Powder ◽  
Inert Material ◽  
Normal Concrete ◽  
Significant Negative Effect ◽  
Negative Effect

Experimental studies on the properties of cement paste and mortar with the use of limestone powder were carried out. The results show that the replacement with 10% to 30% limestone powder in cement paste can reduce the water requirement for certain flowability. As an inert material, the use of the limestone powder has significant negative effect on the mechanical properties of mortar. However, strength requirement of normal concrete (mortar) can be reached by reducing the water to cementious material ratio, which makes the use of limestone powder as a replacement of cement possible.

scholarly journals Properties of the high burnup structure in nuclear light water reactor fuel

2017 ◽  
Vol 105 (11) ◽  
Author(s):  
Thierry Wiss ◽  
Vincenzo V. Rondinella ◽  
Rudy J. M. Konings ◽  
Dragos Staicu ◽  
Dimitrios Papaioannou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Nuclear Fuel ◽  
Experimental Studies ◽  
Fuel Pellet ◽  
Extended Defects ◽  
Safety Margins ◽  
Fission Gas ◽  
High Burnup ◽  
Formed Structure

AbstractThe formation of the high burnup structure (HBS) is possibly the most significant example of the restructuring processes affecting commercial nuclear fuel in-pile. The HBS forms at the relatively cold outer rim of the fuel pellet, where the local burnup is 2–3 times higher than the average pellet burnup, under the combined effects of irradiation and thermo-mechanical conditions determined by the power regime and the fuel rod configuration. The main features of the transformation are the subdivision of the original fuel grains into new sub-micron grains, the relocation of the fission gas into newly formed intergranular pores, and the absence of large concentrations of extended defects in the fuel matrix inside the subdivided grains. The characterization of the newly formed structure and its impact on thermo-physical or mechanical properties is a key requirement to ensure that high burnup fuel operates within the safety margins. This paper presents a synthesis of the main findings from extensive studies performed at JRC-Karlsruhe during the last 25 years to determine properties and behaviour of the HBS. In particular, microstructural features, thermal transport, fission gas behaviour, and thermo-mechanical properties of the HBS will be discussed. The main conclusion of the experimental studies is that the HBS does not compromise the safety of nuclear fuel during normal operations.

Effect of Wood Filler Concentration on Physical and Mechanical Properties of PLA-Based Composites

2021 ◽  
Vol 887 ◽  
pp. 110-115
Author(s):  
G.A. Sabirova ◽  
R.R. Safin ◽  
N.R. Galyavetdinov
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Composite Materials ◽  
Impact Strength ◽  
Wood Flour ◽  
Experimental Studies ◽  
Physical And Mechanical Properties ◽  
Filler Concentration ◽  
High Concentration

This paper presents the findings of experimental studies of the physical and mechanical properties of wood-filled composites based on polylactide (PLA) and vegetable filler in the form of wood flour (WF) thermally modified at 200-240 °C. It also reveals the dependence of the tensile strength, impact strength, bending elastic modulus, and density of composites on the amount of wood filler and the temperature of its thermal pre-modification. We established that an increase in the concentration of the introduced filler and the degree of its heat treatment results in a decrease of the tensile strength, impact strength and density of composite materials, while with a lower binder content, thermal modification at 200 °C has a positive effect on bending elastic modulus. We also found that 40 % content of a wood filler heated to 200 °C is sufficient to maintain relatively high physical and mechanical properties of composite materials. With a higher content of a wood filler, the cost can be reduced but the quality of products made of this material may significantly deteriorate. However, depending on the application and the life cycle of this product, it is possible to develop a formulation that includes a high concentration of filler.

Experimental studies and theoretical analysis of the residual properties of three-span small-scale continuous concrete slabs after a fire

2021 ◽  
pp. 103481
Author(s):  
Yong Wang ◽  
Gongchen Wang ◽  
Zhaohui Huang ◽  
Yuner Huang ◽  
Benmiao Wang ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Experimental Studies ◽  
Small Scale ◽  
Concrete Slabs ◽  
Residual Properties

scholarly journals RESEARCH OF PHYSICAL AND MECHANICAL PROPERTIES OF WOOD-FIBER MATERIALS

2020 ◽  
pp. 451-457
Author(s):  
Aleksandr Yur'yevich Vititnev ◽  
Yuriy Davydovich Alashkevich ◽  
Natal'ya Geral'dovna Chistova ◽  
Roman Aleksandrovich Marchenko ◽  
Venera Nurullovna Matygullina
Keyword(s):  
Mechanical Properties ◽  
Wood Fiber ◽  
Experimental Studies ◽  
Physical And Mechanical Properties ◽  
Production Method ◽  
Strength Properties ◽  
Grinding Process ◽  
Technological Parameters ◽  
Fiber Materials ◽  
Traditional Construction

This paper presents the results of experimental studies of the physical and mechanical properties of wood-fiber boards of the wet production method when regulating the design and technological parameters of the grinding process. This allowed us to determine the influence of the working clearance between the grinding discs and the concentration of fibre mass with the subject to of quality change wood fiber after defibrator using the developed construction of the disc fibrillation action on the physico-mechanical properties of boards. As a result of the experiment, regression models were obtained that adequately describe the studied grinding process and allow predicting the values of physical and mechanical properties of the finished product depending on the established  parameters process. A comparative analysis of the size and quality characteristics of the fiber semi-finished product and its fractional composition when using a developed construction the disc of refiner fibrillation action and a traditional design used in industry is carried out. The preferential efficiency of the grinding process under the fibrillating effect the disc of refiner in comparison with the traditional construction disc of refiner is established. As a result, there is a significant improvement in the quality indicators of the fiber semi-finished product and its composition due to the formation and predominance in the total mass of long and thin, respectively, flexible fibrillated fibers with high tile-forming properties, which allows to increase the strength properties of the product (by 20–25%), without using binding resins.

scholarly journals RESEARCH INTO MECHANICAL PROPERTIES OF MINCED MEAT AND FINISHED PRODUCTS

2017 ◽  
Vol 4 ◽  
pp. 43-51
Author(s):  
Yuriy Suсhenko ◽  
Vladislav Suсhenko ◽  
Mikhail Mushtruk ◽  
Vladimir Vasyliv ◽  
Yuriy Boyko
Keyword(s):  
Mechanical Properties ◽  
Mechanical Characteristics ◽  
Raw Materials ◽  
Meat Products ◽  
Tissue Fluid ◽  
Strained State ◽  
Inorganic Substances ◽  
Minced Meat ◽  
Cutting Mechanisms

Studies were conducted of the stressed-strained state of biopolymers of meat, which were exposed to the processes of elastic, residual and highly elastic deformation at cutting and mincing. Analysis of the structure of this natural biopolymer and the evaluation of mechanical characteristics of meat under normal and low temperatures are important factors that are taken into account for the rational selection of meat mincing machines and tools in the production of meat products, minced meat, semi-finished and sausage products. The structure of meat is a system of structured protein fibers, impregnated with tissue fluid, which is protein sol that contains organic and inorganic substances, soluble in it. The tissues that the meat is composed of belong to natural biopolymers, so conducting analytical studies into mechanical properties of meat within the framework of our understanding of the mechanics of polymers will make it possible to improve mincing processes, employed during manufacturing of meat products. In order to prevent meat overheating, the mincing process is performed at several stages. For example, in cutting mechanisms of choppers, they use a row of knives and grids with holes, diameter of which gradually changes from the original size of0.06 mto 0.003-0.002 min the outlet grids. Quality indicators of the finished products are affected by mechanical characteristics of raw materials and the way the cutting process is carried out. In the course of conducted analysis it was found that in modern food production there remain unresolved important problems, which address current issues, related to rheological and structural mechanical properties of meat raw material. First of all, it concerns theoretical and practical developments that enhance an understanding of physico-chemical and mechanical properties of raw materials, which will make it possible to develop theoretical foundations and experimentally substantiate the new conceptual approach to solving the task of improving the quality of semi-finished products and durability of equipment at meat processing enterprises of APC. The research is the basis for constructive and technological solutions, choice of mode, kinematic and dynamic parameters of cutting devices, steel and wear resistant coatings for cutting tools that provide saving of energy and materials at meat mincing, high quality of minced meat. and finished products and appropriate service life of the equipment. It was established that in order to determine characteristics of the strained state of meat, it is necessary to apply a circular diagram of loading-unloading, which allows analysis of behavior of the sample in a closed cycle of changing in external load. An analysis indicates a very large dependence of meat elasticity module on temperature. Dependences of this kind are generally characteristic of polymer bodies.

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