scholarly journals Discrete-continuous three-element model of impact device

2021 ◽  
Vol 2131 (3) ◽  
pp. 032091
Author(s):  
A M Slidenko ◽  
V M Slidenko ◽  
S G Valyukhov
Keyword(s):  
Boundary Problem ◽  
Fourier Method ◽  
Mathematic Model ◽  
Initial Boundary ◽  
Element Model ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Initial Boundary Problem ◽  
Impact Device ◽  
The Impact

Abstract There have been examined the mathematic model of the impact device provided for geological materials destruction. Basic elements of the impact device are variable cross-section tool, striker and impact device body. The interaction of these elements is described as a movement of two discrete mass and the rod in the presence of rigid and dissipative connections. One equation in partial derivatives and two ordinary differential equations associated by initial and boundary conditions represent the initial-boundary problem. The numerical method parameters of which are determined at tests problems solution by Fourier method is used for looking for solutions of mixed initial-boundary problem. Researches are made, and parameters determining the damping efficiency of tool, striker and impact device body oscillations are evaluated.

scholarly journals On solution of initial-boundary problem, connected with longitudinal impact of elastic-viscous rod

1987 ◽  
pp. 112
Author(s):  
S.S. Kritskaia ◽  
D.I. Rogach
Keyword(s):  
Linear Equation ◽  
Boundary Problem ◽  
Finite Length ◽  
Fourier Method ◽  
Initial Boundary ◽  
Longitudinal Impact ◽  
Initial Boundary Problem ◽  
Rod Of Finite Length

We conduct the solution, by Fourier method, of the problem about longitudinal oscillations caused by impact to one end of elastic-viscous rod of finite length with variable lateral section in the case when the condition of fixation of another end of the rod is represented by linear equation in displacement and deformation.

The Impact of Local Heating Time of the Compressed Column on its Stability

2020 ◽  
Vol 17 (2) ◽  
pp. 7902-7914
Author(s):  
S. Uzny ◽  
T. Skrzypczak ◽  
L. Kutrowski
Keyword(s):  
Heat Flux ◽  
Boundary Problem ◽  
Local Heating ◽  
Initial Boundary ◽  
Local Heat ◽  
Heating Time ◽  
Load Parameter ◽  
Initial Boundary Problem ◽  
The Stability ◽  
The Impact

The present paper considers the influence of activity time of a local heat source on the stability of a supporting system (column) subjected to the Euler’s external load. Constant heat having impact on the entire circumference of the column on a chosen length was adopted as the boundary heat flux. The formulation and solution of the initial-boundary problem of heat transport in the column was presented by means of the Finite Element Method (FEM). The stiffness of particular segments of the column, onto which it was divided, was determined on the basis of the obtained temporary temperature distributions. The boundary problem of stability of the system was formulated and solved with the inclusion of material changes, resulting from the influence of high temperature. The paper presents the results of numerical simulations, defining the change of a critical load parameter of the system as the function of heating time with the inclusion of stiffness of the supported structure and various positions of the heat flux influence

RESEARCH OF THE IMPACT DEVICE MODEL OF THE ROD TYPE BY DIFFERENCE METHOD

2020 ◽  
pp. 73-80
Author(s):  
А.М. Слиденко ◽  
В.М. Слиденко
Keyword(s):  
Boundary Value Problem ◽  
Difference Method ◽  
Model Problem ◽  
Boundary Value ◽  
Initial Boundary ◽  
Initial Boundary Value Problem ◽  
Cross Sectional ◽  
Impact Device ◽  
Initial Boundary Value ◽  
The Impact

Приводится анализ механических колебаний элементов ударного устройства с помощью модели стержневого типа. Ударник и инструмент связаны упругими и диссипативными элементами, которые имитируют их взаимодействие. Аналогично моделируется взаимодействие инструмента с рабочей средой. Сформулирована начально-краевая задача для системы двух волновых уравнений с учетом переменных поперечных сечений стержней. Площади поперечных сечений определяются параметрическими формулами при сохранении объемов стержней. Параметрические формулы позволяют получать различного вида зависимости площади поперечного сечения стержня от его длины. Начальные условия отражают физическую картину взаимодействия инструмента с ударником и рабочей средой. Краевые условия описывают контактные взаимодействия ударника с инструментом и последнего с рабочей средой. В качестве модельной задачи рассматривается соударение ударника и инструмента через элемент большой жесткости. Начально-краевая задача исследуется разностным методом. Проводится сравнение решений задачи, полученных с помощью двухслойной и трехслойной разностных схем. Такие схемы реализованы в общей компьютерной программе в системе Mathcad. Показано, что при вычислениях распределения нормальных напряжений по длине стержня лучшими свойствами относительно устойчивости обладает двухслойная схема The article gives the analysis of mechanical vibrations of the impact device elements using the model of the rod type. The hammer and the tool are connected by elastic and dissipative elements that simulate their interaction. The interaction of the tool with the processing medium is simulated in a similar way. An initial boundary-value problem is formulated for a system of two wave equations taking into account the variable cross sections of the rods. Cross-sectional areas are determined by parametric formulas maintaining the volume of the rods. Parametric formulas allow one to obtain various dependence types of the cross-sectional area of the rod on its length. The initial and boundary conditions reflect the physical phenomenon of the tool interaction with the processing medium, and also describe the contact interactions of the hammer with the tool. The impacting of the hammer and the tool through an element of high rigidity is considered as a model problem. To control the limiting values, the solution of the model problem by the Fourier method is used. The initial-boundary-value problem is investigated by the difference method. A comparison of solutions obtained for the two-layer and three-layer difference schemes is given. Such schemes are realized in a common computer program in the Mathcad. It is shown that the two-layer scheme has the best properties in relation to stability while calculating the distribution of normal voltage along the length of the rod

scholarly journals Eco-friendly technology of manufacturing complex products made of composites

2019 ◽  
Vol 140 ◽  
pp. 02004
Author(s):  
Aleksey Ignatov ◽  
Rustam Subkhankulov
Keyword(s):  
Composite Materials ◽  
Cross Section ◽  
Manufacturing Process ◽  
Volume Fraction ◽  
Turbine Blades ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Technological Parameters ◽  
Technological Support ◽  
The Impact

Numerous studies in application of modern composite materials show that their advantages can be successfully implemented in manufacturing «smart» products. This study proposes an improved technological method of manufacturing multilayer environmentally friendly products with a variable cross section, which allows us to expand the possibilities of using modern polymer composite materials (PCM). The technology allows manufacturing products of the most complex geometric shapes, such as wind turbine blades. The aim of the study is the technological support of engineering production in the manufacture of multilayer products of variable cross section made from PCM. Scientific novelty consists in identifying the patterns of implementation and management of the manufacturing process of multilayer products of variable cross-section, and establishing the influence of structural and technological parameters of the manufacturing process on their operational characteristics. The relationship between the pressure of a hot directed air stream and the volume fraction of pores in the hardened material of a multilayer composite product with a variable cross section during layer-by-layer application is investigated. During the study, fundamental and applied principles of mechanical engineering technology, material resistance, adhesion theory, mathematical statistics tools and software were used to process the results of the experiment. Based on the results of laboratory studies, a methodology has been developed for effective prediction of pore content in the manufacturing of composite products. The introduction of the presented technology and the corresponding original methodology into production will reduce the complexity and energy costs of manufacturing composite products, improve their quality and reduce the impact of toxic components from composite materials on workers.

The Dynamics of Rotor-Bearing Systems Using Finite Elements

1976 ◽  
Vol 98 (2) ◽  
pp. 593-600 ◽  
Author(s):  
H. D. Nelson ◽  
J. M. McVaugh
Keyword(s):  
Element Model ◽  
Variable Cross Section ◽  
Distributed Parameter ◽  
Viscous Damping ◽  
Variable Cross ◽  
Mass Analysis ◽  
Lumped Mass ◽  
Rotatory Inertia ◽  
Rigid Disks ◽  
Rotor Bearing

A procedure is presented for dynamic modeling of rotor-bearing systems which consist of rigid disks, distributed parameter finite rotor elements, and discrete bearings. The formulation is presented in both a fixed and rotating frame of reference. A finite element model including the effects of rotatory inertia, gyroscopic moments, and axial load is developed using the consistent matrix approach. A reduction of coordinates procedure is utilized to model elements with variable cross-section properties. The bearings may be nonlinear, however, only the linear stiffness and viscous damping case is considered. The natural whirl speeds and unbalance response of a typical overhung system is presented for two sets of bearing parameters: (i) undamped isotropic, (ii) undamped orthotropic. A comparison of results is made with an independent lumped mass analysis.

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