New construction: zero cycle aspects, modern methods and promising materials

This work is aimed at studying the physicochemical processes and establishing the functional dependence of the strength parameters on the sulfur concentration in the composite. The introduction of sulfur in the composite contributes to a change in strength properties, an increase in frost resistance. The dependence of strength on sulfur concentration was studied. The experimental function is determined analytically by solving a system of linear algebraic equations consisting of canonical equations of a given approximating function. The behavior of the dependence of strength on the concentration of nanotubes at two intervals is plotted graphically. Further studies are needed to gain a complete picture of the composite and its characteristics. Nowadays, the results of determining the deformative characteristics are being processed, the impact of the water-cement ratio, the equivalent economic assessment are being studied. At present, an analytical description of the physicochemical and physicomechanical dependencies is being carried out, and an aggregate mathematical model is being built. The results will be presented to the public at subsequent scientific and research conferences.

Download Full-text

Mathematical model of piston-tool interaction in rock fracture by impact

MINING INFORMATIONAL AND ANALYTICAL BULLETIN ◽

10.25018/0236-1493-2020-7-0-94-103 ◽

2020 ◽

pp. 94-103

Author(s):

A. B. Zhabin ◽

I. M. Lavit ◽

A. V. Polyakov ◽

Z. E. Kerimov

Keyword(s):

Finite Difference ◽

Boundary Value Problems ◽

Variational Equation ◽

Rock Fracture ◽

Boundary Value ◽

Calculation Error ◽

Algebraic Equations ◽

Time Curve ◽

Linear Algebraic Equations ◽

The Impact

The authors justify a computation model of a machine percussion system simulated by elastic cylindrical rods subjected to maximal axial load at minimal strain. Rock mass is assumed as a perfectly solid block. The piston and tool are described by the values of length, cross-section area, density and Young’s modulus. The model determines the force applied by the tool on the rock as function of time. It is assumed that transverse displacements and velocities of the rods are negligeable as compared with the axial displacements and velocities, while the rods are free from the action of the external forces different from the restraining forces. The variational equation expresses the principle of possible displacements. The variations are independent of time. The initial and boundary conditions are considered. The variational equation is solved using the method of straight lines, with replacement of a time differentiation operator by the finite difference operator. The problem reduces to the successive solving of boundary value problems with variable right-hand sides. The finite difference scheme is the approved implicit scheme of Crank-Nicolson. The boundary value problems are solved using the finite element method at each step of integrating. As a result, the variational equation transforms into a system of linear algebraic equations, and the reduced solution of this system yields the wanted force. The calculations are illustrated by the tool press force-time curve plotted with a step of 0.1 µs for hydropercussion machine G100 by Rammer, Finland. The relative calculation error of the impact duration and maximal force (in absolute magnitude) is not higher than 0.1%.

Download Full-text

Comparison of Linear Vortex Panel Method and Finite Volume Method for Calculation of Generated Lift in Potential Flow Over Two-Dimensional Car Bodies

10.21203/rs.3.rs-107656/v1 ◽

2020 ◽

Author(s):

Saeid Moammaei ◽

Mehran Khaki Jamei ◽

Morteza Abbasi

Keyword(s):

Pressure Distribution ◽

Lift Coefficient ◽

Control Point ◽

Panel Method ◽

The Body ◽

Aerodynamic Load ◽

Two Dimensional ◽

Algebraic Equations ◽

Linear Algebraic Equations ◽

The Impact

Abstract This paper describes one of the aspects of the panel method to analyze the aerodynamic characteristics of a sedan. The linear vortex panel method has been developed to simulate the ideal flow over a two-dimensional arbitrary car and, it also calculates the aerodynamic load on the body. By satisfying the boundary conditions on each control point, our linear algebraic equations are obtained. The results are sensitive to the distribution of the panels over the body thus the body is broken up equally into very small panels. After solving the set of equations, the vortices strength is obtained and the pressure distribution for the upper and the lower surface of the body is calculated. The impact of the angle of attack on the aerodynamic behavior of the intended car is investigated and it is found that the lift coefficient increases with the free stream angle from -4 to 4. The accuracy of the results has been determined by checking them against the standard CFD data. The pressure distribution trend is found very much in confirmation with the CFD results, however, a discrepancy at the rear end is observed. Therefore, it can be concluded that this method does not seem practical for geometries with steep slopes in the rear part of the car. Finally, both methods are applied to the other modified geometries with lower slopes at the rear section and the results compare well with the fluent.

Download Full-text

Technological aspects of cased wells construction with cyclical-flow transportation of rock

Записки Горного института ◽

10.31897/pmi.2020.6.2 ◽

2021 ◽

Vol 246 ◽

pp. 610-616

Author(s):

Andrei KONDRATENKO

Keyword(s):

Rock Mass ◽

High Performance ◽

Sedimentary Rock ◽

Mining Industry ◽

Economic Assessment ◽

Soil Mass ◽

Strength Properties ◽

Technology Application ◽

Casing Pipe ◽

The Impact

A high-performance technology for constructing cased wells is proposed. Essence of the technology is the advance insertion of the casing pipe into the sedimentary rock mass and the cyclical-flow transportation of the soil rock portions using the compressed air pressure supplied to the open bottomhole end of the pipe through a separate line. Results of mathematical modeling for the process of impact insertion of a hollow pipe into a soil mass in horizontal and vertical settings are considered. Modeling of the technology is implemented by the finite element method in the ANSYS Mechanical software. Parameters of the pipe insertion in the sedimentary rock mass are determined - value of the cleaning step and the impact energy required to insert the pipe at a given depth. Calculations were performed for pipes with a diameter from 325 to 730 mm. Insertion coefficient is introduced, which characterizes the resistance of rocks to destruction during the dynamic penetration of the casing pipe in one impact blow of the pneumatic hammer. An overview of the prospects for the application of the proposed technology in geological exploration, when conducting horizontal wells of a small cross-section using a trenchless method of construction and borehole methods of mining, is presented. A variant of using the technology for determining the strength properties of rocks is proposed. Some features of the technology application at industrial facilities of the construction and mining industry are considered: for trenchless laying of underground utilities and for installing starting conductors when constructing degassing wells from the surface in coal deposits. Results of a technical and economic assessment of the proposed technology efficiency when installing starting conductors in sedimentary rocks at mining allotments of coal mines are presented.

Download Full-text

Influence of the new construction to settlement of historical building when accounting hardening of medium sand in basement

MATEC Web of Conferences ◽

10.1051/matecconf/201825104047 ◽

2018 ◽

Vol 251 ◽

pp. 04047

Author(s):

Dmitriy Chunyuk ◽

Daria Rasskazova

Keyword(s):

Urban Areas ◽

Single Layer ◽

Strength Properties ◽

Calculation Model ◽

Historical Building ◽

Existing Building ◽

New Construction ◽

Building Operation ◽

The Impact

Currently, a number of difficulties arise in the construction of dense urban areas, as well as in the reconstruction and superstructure of existing buildings and structures. Often when carrying out geological scene investigation, it is not possible to determine the strength parameters of the soil directly under the foundation. In most cases, this leads to understating of its characteristics, which is reflecting in the excessive economic costs resulting from the need to strengthen the existing building structure. However, in many situations, this can be discarded, justifying it by calculations. In this paper is shows the performed series of numerical experiments and were analyzed the changes of existing building foundation settlements, taking into account its long-term exploitation in assessing the impact of new construction. The base had defined by a single-layer half-space with a limited depth of deformation zone and composed of medium-sized sand. PLAXIS 2D software was chosen to create the calculation model. When processing the results, it was possible to identify a certain dependence that allows estimating the maximum settlement of existing building in the impact assessing from new construction taking into account the duration of building operation. The obtained data prove the necessity to take into account the change in strength properties of soils caused by long-term loads action of structures.

Download Full-text

CONSTRUCTION OF SYSTEM FOR ORGANIZATION OF PRODUCTION IN CONDITIONS OF TECHNICAL AND ECONOMIC RISKS OF INDUSTRIAL ENTERPRISES

Issues of radio electronics ◽

10.21778/2218-5453-2018-10-115-124 ◽

2018 ◽

pp. 115-124

Author(s):

V. V. Kurlov ◽

A. V. Kurlov ◽

A. G. Stepanov ◽

V. G. Farafonov

Keyword(s):

The State ◽

Algebraic Equations ◽

Electronic Industry ◽

Time Duration ◽

Industrial Enterprises ◽

Radio Electronic ◽

Linear Algebraic Equations ◽

Organization Of Production ◽

The Impact ◽

Economic Risks

One of the key components of effective production organization at the enterprises of the radio electronic industry is the need to take into account the risk environment, and take measures to minimize the likelihood of risk occurrence. The main problem is the probabilistic nature of the manifestation of risk. The probability is manifested in the realization of the risk and its duration, which, in the final analysis, will lead to financial losses. The article proposes an approach to building the core of the system of technical and economic risks and their interrelationship in the organization of production at the enterprises of the radio electronic industry. In the article it is proposed to use basic modules for estimating the limiting probabilities of various states of technical and economic risks for which special systems of linear algebraic equations are developed. In this case, to determine (calculate) the estimate, we can use the results of solving a system of linear algebraic equations. In addition, these results allow for the assessment of the stationary state of the basic modules of the technical and risks system in the organization of production at the enterprises of the radio electronic industry. When solving a system of algebraic equations, it is suggested to use the standard approach, namely, the limit transformation of the system of Kolmogorov's differential equations for state probabilities. The article concludes that to assess the impact of technical and economic risks on the effectiveness of the organization of production of enterprises of the electronic industry, it is necessary to assess the likelihood of finding a system of technical and economic risks in the state of their implementation. The results of such an assessment will allow to determine two main components - the intensity of the events' flows associated with the emergence (implementation) of technical and economic risks and the time (duration) of their finding in the state of realization (negative state).

Download Full-text

The Influence of Armor Material Parameters on the Penetration by Long-Rod Projectiles

Volume 4: Fluid Structure Interaction, Parts A and B ◽

10.1115/pvp2006-icpvt-11-93716 ◽

2006 ◽

Author(s):

William P. Walters ◽

Cyril L. Williams

Keyword(s):

Material Properties ◽

Exact Analytical Solution ◽

Functional Dependence ◽

Perturbation Solution ◽

Tungsten Heavy Alloy ◽

Algebraic Equations ◽

Third Order ◽

Long Rod ◽

The Impact ◽

Nonlinear Nature

The Alekseevski-Tate equations have long been used to predict the penetration, penetration velocity, rod velocity, and rod erosion of long-rod projectiles or kinetic-energy penetrators [1]. These nonlinear equations were originally solved numerically, then by the exact analytical solution of Walters and Segletes [2, 3]. However, due to the nonlinear nature of the equations, the penetration was obtained implicitly as a function of time, so that an explicit functional dependence of the penetration on material properties was not obtained. Walters and Williams [4, 5, 6] obtained the velocities, length, and penetration as an explicit function of time by employing a perturbation solution of the non-dimensional Alekseevski-Tate equations. Algebraic equations were obtained for a third-order perturbation solution which showed excellent agreement with the exact solution of the Tate equations for tungsten heavy alloy rods penetrating a semi-infinite armor plate. The current paper employs this model to rapidly assess the effect of increasing the impact velocity of the penetrator and increasing the armor material properties (density and target resistance) on penetration. This study is applicable to the design of hardened targets.

Download Full-text

About one method of numeral decision of differential equalizations in partials using geometric interpolants

CPT2020 The 8th International Scientific Conference on Computing in Physics and Technology Proceedings ◽

10.30987/conferencearticle_5fce27708eb353.92843700 ◽

2020 ◽

Author(s):

Evgeniy Konopatskiy ◽

Olga Voronova ◽

Andrei Bezditnyi ◽

Oksana Shevchuk

Keyword(s):

Differential Equations ◽

Algebraic Curves ◽

Geometric Model ◽

Bernstein Polynomials ◽

Analytical Description ◽

Multidimensional Space ◽

Algebraic Equations ◽

Approximation Solution ◽

Nodal Points ◽

Linear Algebraic Equations

The article presents a new vision of the process of approximating the solution of differential equations based on the construction of geometric objects of multidimensional space incident to nodal points, called geometric interpolants, which have pre-defined differential characteristics corresponding to the original differential equation. The incidence condition for a geometric interpolant to nodal points is provided by a special way of constructing a tree of a geometric model obtained on the basis of the moving simplex method and using special arcs of algebraic curves obtained on the basis of Bernstein polynomials. A fundamental computational algorithm for solving differential equations based on geometric interpolants of multidimensional space is developed. It includes the choice and analytical description of the geometric interpolant, its coordinate-wise calculation and differentiation, the substitution of the values of the parameters of the nodal points and the solution of the system of linear algebraic equations. The proposed method is used as an example of solving the inhomogeneous heat equation with a linear Laplacian, for approximation of which a 16-point 2-parameter interpolant is used. The accuracy of the approximation was estimated using scientific visualization by superimposing the obtained surface on the surface of the reference solution obtained on the basis of the variable separation method. As a result, an almost complete coincidence of the approximation solution with the reference one was established.

Download Full-text

Does kraft hardwood and softwood pulp viscosity correlate to paper properties?

TAPPI Journal ◽

10.32964/tj15.10.643 ◽

2016 ◽

Vol 15 (10) ◽

pp. 643-651 ◽

Cited By ~ 1

Author(s):

ROBERT J. OGLESBY ◽

HUMPHREY J. MOYNIHAN ◽

RICARDO B. SANTOS ◽

ASHOK GHOSH ◽

PETER W. HART

Keyword(s):

Physical Properties ◽

Strength Loss ◽

Strength Properties ◽

Clear Correlation ◽

Paper Properties ◽

Physical Strength ◽

Pulp Viscosity ◽

Softwood Pulp ◽

The Impact ◽

Orthogonal projectors and systems of linear algebraic equations

Сибирский журнал вычислительной математики ◽

10.15372/sjnm20200306 ◽

2020 ◽

Keyword(s):

Algebraic Equations ◽

Linear Algebraic Equations ◽

Orthogonal Projectors

Download Full-text

On Improved Approximate Solution of the Fredholm Integral Equation

Computational Methods in Applied Mathematics ◽

10.2478/cmam-2006-0014 ◽

2006 ◽

Vol 6 (3) ◽

pp. 264-268

Author(s):

G. Berikelashvili ◽

G. Karkarashvili

Keyword(s):

Integral Equation ◽

Approximate Solution ◽

Fredholm Integral Equation ◽

Algebraic Equations ◽

Order Convergence ◽

One Dimensional ◽

Averaging Operator ◽

Linear Algebraic Equations ◽

Convergence Solution

AbstractA method of approximate solution of the linear one-dimensional Fredholm integral equation of the second kind is constructed. With the help of the Steklov averaging operator the integral equation is approximated by a system of linear algebraic equations. On the basis of the approximation used an increased order convergence solution has been obtained.

Download Full-text