scholarly journals On ways to increase protection of special structures from impact action

2021 ◽  
pp. 52-57
Author(s):  
Andriy Andrukhiv ◽  
Andriy Baranov ◽  
Nadiia Huzyk ◽  
Bohdan Sokil ◽  
Mariia Sokil
Keyword(s):  
Mechanical Characteristics ◽  
Dynamic Effect ◽  
External Action ◽  
Engineering Structures ◽  
Discrete Function ◽  
Impact Action ◽  
Protective Element ◽  
Protective Structures ◽  
The Impact ◽  
Physical And Mechanical Characteristics

The technique of research of dynamic processes of elements of engineering constructions of special purpose from explosive action of projectiles is developed. Elastically reinforced beams with hinged ends were chosen for the physical model of elements of engineering structures. It is assumed that the elastic properties of the latter satisfy the nonlinear technical law of elasticity. A mathematical model of the process of a series of impact actions of projectiles at different points of the element of the protective structure is constructed. The latter is a boundary value problem for a partial differential equation. Its peculiarity is that the external dynamic action is a discrete function of linear and time variables. To determine the dynamic effect of a series of impacts on the object under study, and thus the level of protection of the structure, the basic ideas of perturbation theory methods are extended to new classes of systems. This allowed to obtain an analytical dependence of the deformation of the elastically reinforced element on the basic physical and mechanical characteristics of the material of the protective element, its reinforcement and the characteristics of the external action of the projectiles. It is shown that the most dangerous cases, given the security of the structure, are those when the impact is repeated at equal intervals, in addition, the point of impact is closer to the middle of the protective element. The obtained theoretical results can be the basis for selection at the stage of designing the main physical and mechanical characteristics of the elements of engineering structures and their reinforcement in order to reliably protect personnel and equipment from the maximum possible impact on it of the shock series of projectiles. The reliability of the obtained results is confirmed by: a) generalization of widely tested methods to new classes of dynamical systems; b) obtaining in the limit case the consequences known in scientific sources concerning the linearly elastic characteristics of the elements of protective structures; c) their consistency with the essence of the physical process itself, which is considered in the work.

Impact action of a projectiles on special protective structures and ways to increase their protective capacity

2021 ◽  
pp. 95-100
Author(s):  
A. Andrukhiv ◽  
A. Baranov ◽  
N. Huzyk ◽  
B. Sokil ◽  
M. Sokil
Keyword(s):  
Soil Layer ◽  
Strength Characteristics ◽  
Protective Structure ◽  
Impact Action ◽  
Dirac Delta ◽  
Wood Flooring ◽  
Protective Element ◽  
Applied Forces ◽  
Protective Structures ◽  
Elastic Elements

A method for studying the reaction of elastic elements of protective structures to a series of impact actions of shells has been developed. In the work, the elastic elements of the protective structure are modeled by homogeneous beams, and the dynamic action of the shells is simulated by instantaneous point-applied forces. A mathematical model of this dynamic process is constructed, which is a boundary value problem for a hyperbolic equation with an irregular right-hand side. The latter is described using Dirac delta functions. Cases of both fixed and free ends of protective elements are considered. The main ideas of perturbation methods are used for the researches carried out in the work. Analytical dependences for the description of elastic deformations of a protective element which are basic for definition of its strength characteristics are received. They and the graphical dependences built on their basis for specific cases show that the dynamic deformations of the protective element for the fixed ends are greater in the case of the projectile closer to its middle, at the same time for the free ends – closer to the end. With regard to the modernization of protective structures, the dynamic effect on their elements can be reduced by using elastic reinforcement or changing the method of fixing the ends of the protective element: elastic or with a certain angle of inclination of the bearing surfaces. It is proposed to use special plastics, soil layer, flexible wood flooring, etc. as elastic reinforcement. The technique used in the work is the basis for determining the strength characteristics of protective elements, and from so – to check the reliability of the protective structure; study of the dynamics of protective and similar types of structures, taking into account the nonlinear characteristics of the elastic elements of protective structures; study of more complex oscillations of elements of protective structures. In the case of a series of impacts, it is obvious that the amplitude of deflection of the protective element after each impact will increase over time, because the model does not take into account the force of viscoelastic friction. These tasks will be the subject of further research.

STUDYING THE IMPACT OF MODIFICATING ADDITIVES ON THE PHYSICAL AND MECHANICAL CHARACTERISTICS OF THE HYPROFIBER MATERIALS

2018 ◽  
Vol 133 ◽  
Author(s):  
Bunyod Gayratovich Igamberdiev ◽  
◽  
Rolan Sobirovich Yulyakshiev ◽  
Sadokat Abdullazhonovna Karimova ◽  
◽  
...  
Keyword(s):  
Mechanical Characteristics ◽  
The Impact ◽  
Physical And Mechanical Characteristics

scholarly journals Modeling the processes of friction and wear under dynamic influences on the tribosystem

2020 ◽  
Vol 97 (3) ◽  
pp. 45-49
Author(s):  
A. Voitov ◽  
Keyword(s):  
Wear Rate ◽  
Coefficient Of Variation ◽  
Friction And Wear ◽  
Operating Time ◽  
Dynamic Effect ◽  
External Action ◽  
Volumetric Wear ◽  
Distribution Law ◽  
Sliding Speed ◽  
The Impact

On the basis of the performed analysis of works devoted to the increase in the wear rate due to the dynamic effect on the tribosystem, expressions were obtained for modeling the processes of friction and wear when changing the external influence. Based on the assumption that the dynamic impact obeys the normal distribution law, the coefficient of variation of the volumetric wear rate. The simulation of the change in the coefficient of variation when changing the load and sliding speed on the tribosystem, as well as the number of steps of changing the load and operating time at each stage. It was found that in the absence of fluctuations in the load and sliding speed, the coefficient of variation of the volumetric wear rate is 1. With an increase in the value of the standard deviation of the external action and the number of steps of change in the action, the coefficient of variation of the volumetric wear rate increases to values 2,59, those volumetric wear rate increases by 1,125 … 2,59 times. This is confirmed by experimental dependencies. The simulation results are adequate to the experimental results with a confidence level 0,9. Calculated modeling error for each series of experiments, which does not exceed 11,03 %. It was found that when changing the power of the bully tribosystem Wb, which is defined as the product of the load and the sliding speed, the coefficient of variation of the volumetric wear rate increases by 1,25 … 4,68 times. Taking into account the range of changes in the external impact and the operating time at each stage of change in the impact will provide information in the form of a coefficient of increasing the wear rate.

scholarly journals THE IMPACT OF PRESCRIPTION-TECHNOLOGICAL FACTORS ON PHYSICO-MECHANICAL CHARACTERISTICS OF FINE-GRAINED CONCRETE WITH THE CARBON PHASE

2016 ◽  
Vol 2 (1) ◽  
pp. 130-133
Author(s):  
Лопанов ◽  
Aleksandr Lopanov ◽  
Фанина ◽  
Evgeniya Fanina ◽  
Томаровщенко ◽  
...  
Keyword(s):  
Mechanical Characteristics ◽  
Cement Matrix ◽  
Carbon Phase ◽  
Cement Ratio ◽  
Technological Factors ◽  
Fine Grained ◽  
Cement Binder ◽  
The Impact ◽  
Physical And Mechanical Characteristics ◽  
Modifying Additive

The article presents the research results of physical and mechanical characteristics of carbon-containing resistive materials based on cement binder. The regulation limit of the compressive strength of the composites was carried out using mechanochemical methods. Synthesized modifying additive on the basis of ether polycarboxylates, salts of iron and of shungite to reduce water-cement ratio and permeability of conductive fine-grained concrete, as well as to improve the strength characteristics of the compositions. Studied the morphology of tumors in the cement matrix.

Present Status and Future Problems on the Impact Resistance Performance Design of Civil Engineering Protective Structures

2014 ◽  
Vol 566 ◽  
pp. 10-25 ◽  
Author(s):  
Yoshimi Sonoda
Keyword(s):  
Civil Engineering ◽  
Impact Resistance ◽  
Design Methods ◽  
Current Status ◽  
Research Committee ◽  
Engineering Structures ◽  
Design Concepts ◽  
Protective Structures ◽  
Resistance Performance ◽  
The Impact

There are many civil engineering structures that have different systems and required functions. Their design methods do not have consistent design concepts. Thus, it has been pointed out the necessity of universal concepts on assumed external actions and risk for various structures and on the required level of safety. In order to meet those demands, a research committee as part of Japan Society of Civil Engineers summarizing the basic concepts of impact resistance design. This paper introduces several design methods of structures subjected to impact loads, and presents the current status and remaining issues of establishing new performance-based design methods.

Characterization and Properties of Recycled Cellulose Fibre- Reinforced Epoxy-Hybrid Clay Nanocomposites

2010 ◽  
Vol 654-656 ◽  
pp. 2624-2627 ◽  
Author(s):  
Hatem Alamri ◽  
It Meng Low
Keyword(s):  
Impact Toughness ◽  
Mechanical Characteristics ◽  
Cellulose Fiber ◽  
Cellulose Fibre ◽  
Halloysite Nanotubes ◽  
Clay Nanocomposites ◽  
Nano Clay ◽  
Filler Dispersion ◽  
The Impact ◽  
Physical And Mechanical Characteristics

In this paper, epoxy eco-composites reinforced with recycled cellulose fiber (RCF) and nano-fillers such as nano-clay platelets (30B) and halloysite nanotubes (HNTs), have been fabricated and investigated. The influences of RCF/nano-filler dispersion on the microstructure, physical and mechanical characteristics have been characterized. Results indicate that flexural strength decreased for the majority of study samples due to the poor dispersion of nano-fillers and the existence of voids within the samples. In contrast, impact toughness and fracture toughness were improved for all reinforced samples. The effect of water absorption was positive in terms of enhancing the impact toughness of the composites. Addition of nanoclay was found to increase the porosities of all nanocomposites.

scholarly journals EFFECTS OF HIGH PRESSURE ON THE PRESS IN THE SYNTHESIS CHANGING THE PHYSICAL AND MECHANICAL PROPERTIES OF POLYMER COMPOSITES BASED THERMOPLASTIC ELASTOMER

2016 ◽  
Vol 1 (12) ◽  
pp. 155-159
Author(s):  
Прут ◽  
Eduard Prut ◽  
Черкашина ◽  
Natalya Cherkashina ◽  
Матюхин ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Polymer Composites ◽  
Mechanical Characteristics ◽  
Compaction Pressure ◽  
Thermoplastic Elastomer ◽  
Thermoplastic Elastomers ◽  
Specific Pressure ◽  
Compression Pressure ◽  
The Impact ◽  
Physical And Mechanical Characteristics

This paper presents data on the development of polymer composites by hot pressing based thermoplastic elastomers and the effect of pressure and compressing the mixture a filler matrix final physical and mechanical characteristics of the highly filled composites. The paper deals with the pressure range from 100 MPa to 1 GPa. Composite studied parameters depending on the pressure, density and were tensile strength. Studies conducted for the optimal composite composition comprising a thermoplastic elastomer, 30% and 70% of fine filler lung - dimethylpolysiloxane of silica gel. It has been shown that increasing the value of specific pressure of 200 to 800 MPa, the density of the composite is increased by 10% or more is not changed. By increasing the value of the specific pressure of 200 to 700 MPa tensile strength is increased by 5%. The paper found that with increasing pressure ranging from 700 MPa, the tensile strength does not change in tension, and the curve flattens out. From conducted research on the impact of compaction pressure on the final physical and mechanical characteristics of the highly filled composites can be argued that for the synthesis of the composite with the best features you want to use compression pressure of at least 800 MPa.

BENCH DESIGN AND STUDY OF PHYSICAL AND MECHANICAL CHARACTERISTICS OF A TEAT CUP LINER WITH ANTIBACTERIAL FILLER

2020 ◽  
pp. 22-26
Author(s):  
YURY G. IVANOV ◽  
◽  
YELENA V. MASHOSHINA ◽  
LYUDMILA N. VERLIKOVA ◽  
DARIA G. GELETIY ◽  
...  
Keyword(s):  
Mechanical Characteristics ◽  
Physical And Mechanical Characteristics

Discharge-pulse Geotechnical Electro Discharge Technology of Bases Strengthening

2020 ◽  
Vol 787 (12) ◽  
pp. 63-65
Author(s):  
N.S. Sokolov
Keyword(s):  
Bearing Capacity ◽  
Mechanical Characteristics ◽  
Discharge Pulse ◽  
Zero Values ◽  
Traditional Technologies ◽  
Negative Friction ◽  
Geotechnical Problems ◽  
Physical And Mechanical Characteristics

The problem of increasing the bearing capacity of the base is an relevant problem in modern geotechnical construction. When significant loads are transmitted to the base, the use of traditional technologies is not always justified. Often there is an urgent need to use non-standard ways to strengthen the bases. In many cases, the geotechnical situation is aggravated by the presence of weak underlying layers with unstable physical and mechanical characteristics in engineering-geological sections. When strengthening such bases with the help of traditional piles, the latter can get negative friction, which significantly reduces their bearing capacity on the ground, sometimes reaching zero values. This may lead to additional precipitations of the objects being constructed and constructed in the zone of geotechnical influence. The use of ERT piles in most cases successfully solves many complex geotechnical problems.

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