scholarly journals RESEARCH OF THE STRESS-STRAIN STATE OF THE MAIN CYLINDER OF THE HYDRAULIC PRESS

2019 ◽  
pp. 59-67
Author(s):  
Serhii Nemchynov ◽  
Illya Nachovnyy ◽  
Alexander Khristenko ◽  
Vasyl Babenko
Keyword(s):  
Finite Element ◽  
Strain State ◽  
Hydraulic Press ◽  
Stress Strain ◽  
Element Analysis ◽  
Equivalent Stresses ◽  
Stress Strain State ◽  
Wide Range ◽  
Bottom Zone ◽  
Distribution Of Stresses

In the article the stress-strain state of the main cylinder of the hydraulic press for the manufacturing of large-sized plastic products has been investigated using software of finite-element analysis. It is established that the stress-strain state is characterized by a general and local uneven distribution of stresses and displacements. The nature of the distribution of stresses, deformations, displacements, safety factors along the length of the cylinder allowed conditionally divide the cylinder into three characteristic zones: flange zone, Lame zone, bottom zone. In each of the zones we found the areas in which the maximum stresses and strains are observed. It was found that the maximum equivalent stresses calculated according to the Huber-Mises energy theory of strength are observed on the inner surface of the cylinder, and in their fillets in the zones of the bottom and flange. A comparative analysis of the stresses and displacements determined by the Lame formulas and the finite element method showed that in the Lame zone their values do not change significantly. Studies on the influence of the radius, which varied over a wide range, and the fillet angle, made it possible to establish the region of maximum principal and equivalent stresses and reduce their magnitude. The calculations revealed the fillet region in which the axial tensile stresses act and determine the fillet angle at which the axial stresses are equal in magnitude and sign The study allowed to change the geometry of the cylinder, reduce the stress in the cylinder fillet and its weight. The results of the study can be applied to improve the existing and design of new hydraulic presses of the chemical industry, as well as the basis for further research.

КОНСТРУКТИВНО-ТЕХНОЛОГІЧНІ ОСОБЛИВОСТІ ХВОСТО-ВИХ БАЛОК СІТЧАСТОГО ТИПУ З ПОЛІМЕРНИХ КОМПО-ЗИЦІЙНИХ МАТЕРІАЛІВ ВЕРТОЛЬОТІВ ТРАНСПОРТНОЇ КАТЕГОРІЇ

2020 ◽  
pp. 15-30
Author(s):  
А. Г. Гребеников ◽  
И. В. Малков ◽  
В. А. Урбанович ◽  
Н. И. Москаленко ◽  
Д. С. Колодийчик
Keyword(s):  
Finite Element ◽  
Strain State ◽  
Layer Structure ◽  
Metal Structure ◽  
Element Model ◽  
Stress Strain ◽  
Element Analysis ◽  
Mesh Structure ◽  
Stress Strain State ◽  
Mesh Structures

The analysis of the design and technological features of the tail boom (ТB) of a helicopter made of polymer composite materials (PCM) is carried out.Three structural and technological concepts are distinguished - semi-monocoque (reinforced metal structure), monocoque (three-layer structure) and mesh-type structure. The high weight and economic efficiency of mesh structures is shown, which allows them to be used in aerospace engineering. The physicomechanical characteristics of the network structures are estimated and their uniqueness is shown. The use of mesh structures can reduce the weight of the product by a factor of two or more.The stress-strain state (SSS) of the proposed tail boom design is determined. The analysis of methods for calculating the characteristics of the total SSS of conical mesh shells is carried out. The design of the tail boom is presented, the design diagram of the tail boom of the transport category rotorcraft is developed. A finite element model was created using the Siemens NX 7.5 system. The calculation of the stress-strain state (SSS) of the HC of the helicopter was carried out on the basis of the developed structural scheme using the Advanced Simulation module of the Siemens NX 7.5 system. The main zones of probable fatigue failure of tail booms are determined. Finite Element Analysis (FEA) provides a theoretical basis for design decisions.Shown is the effect of the type of technological process selected for the production of the tail boom on the strength of the HB structure. The stability of the characteristics of the PCM tail boom largely depends on the extent to which its design is suitable for the use of mechanized and automated production processes.A method for the manufacture of a helicopter tail boom from PCM by the automated winding method is proposed. A variant of computer modeling of the tail boom of a mesh structure made of PCM is shown.The automated winding technology can be recommended for implementation in the design of the composite tail boom of the Mi-2 and Mi-8 helicopters.

scholarly journals On the issue of dynamic loading of supporting structures of special wheeled chassis

2019 ◽  
pp. 73-83
Author(s):  
V. I. Tarichko ◽  
P. I. Shalupina
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Dynamic Loading ◽  
Strain State ◽  
Element Model ◽  
Stress Strain ◽  
Full Size ◽  
Equivalent Stresses ◽  
Stress Strain State ◽  
Supporting Structures

The paper focuses on a method for assessing the dynamic loading of the frame of a special wheeled chassis when it moves on roads of various categories. Based on the developed finite element model of the frame, we obtained and analyzed full-size patterns of the stress-strain state of the frame and oscillograms of equivalent stresses in the most loaded zones of the frame.

Mathematical Simulation of Cramped Bending of Sheet Parts Using Finite Element Analysis

2016 ◽  
Vol 685 ◽  
pp. 186-190 ◽  
Author(s):  
Е.V. Eskina ◽  
E.G. Gromova
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Mathematical Simulation ◽  
Process Parameters ◽  
Strain State ◽  
Basic Process ◽  
Ansys Software ◽  
Stress Strain ◽  
Element Analysis ◽  
Stress Strain State

The paper describes the method of manufacture of profiles in cramped bending conditions using polyurethaneThe scope of studies included stress-strain state of elastic die and parent sheet, as well as the influence of the basic process parameters on characteristics of the produced items using ANSYS software.

Using FEM Analysis for Evaluating Lifetime of the Turbine Blades Repaired by Different Kinds of Titanium and Nickel Alloys

2008 ◽  
Vol 47-50 ◽  
pp. 37-40
Author(s):  
Aleksandrs Korjakins ◽  
Sergejs Gluhihs ◽  
Andrejs Popovs ◽  
Aleksandr Tiskunov
Keyword(s):  
Strain State ◽  
Turbine Blades ◽  
Fem Analysis ◽  
Laser Forming ◽  
Stress Strain ◽  
Element Analysis ◽  
Stress Strain State ◽  
Wide Range ◽  
Direct Laser ◽  
Attractive Option

With increasing attention being devoted to the problem of reducing service costs for a wide range of turbines and compressors, an attractive option is repair of damaged blades, instead of replacing them by new ones. A lot of different methods are used to repair blades and other parts of turbines and compressors. The processes of laser metal deposition (LMD) and direct laser forming (DLF) are modern methods used to repair blades made of titanium alloys. In the present study, the finite element analysis (FEM) has been applied to determine the stress-strain state of the repaired blades in service conditions. Different forms and sizes of the damaged zones have been analyzed. Several kinds of alloys, such as Incoloy 903, Carlson C800 and Inconel 718, appropriate for the LMD and DLF methods, have been utilized in repairing the blades. Two kinds of blades, with and without cooling hollows, have been examined. Lifetime of the repaired turbine has been evaluated by comparing the results obtained from the modal and stress-strain state analyses of the repaired and original parts. The results allow evaluating influence of sizes and forms of the damaged zones, as well as choice of the alloys applied, on lifetime of the repaired blades.

scholarly journals Analysis the effects of lightweight concrete in the middle layer of multi-layered reinforced concrete structures on the stress-strain state using the finite element method

2018 ◽  
Vol 196 ◽  
pp. 02022 ◽  
Author(s):  
Elena Korol ◽  
Vu Dinh Tho ◽  
Nguyen Huy Hoang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Strain State ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
The Finite Element Method ◽  
Stress Strain ◽  
Stress Strain State ◽  
Wide Range

The development of methods for the calculating reinforced concrete structures covers a wide range of issues, including the expansion of the application of new innovative materials such as concrete and reinforcement. For usage in the practice of modern construction of multilayer structures made of concrete with different physic-mechanical characteristics, it is compulsory to conduct numerical studies of the stress-strain state of these structures under different types of loading. This article presents an analysis of the influence of the relations between the initial elastic modulus of the outer and middle layers for the stress-strain state and the deflection of three-layer reinforced concrete structures using the finite element method in the program ANSYS Mechanical. Numerical modeling allows comparing the obtained results and building theoretical dependences in a wide range of specified parameters for the construction of sections of multilayer reinforced concrete elements. The obtained scientific results enable to determine rational parameters for modeling various structural solutions of multilayer reinforced concrete structures. This would limit the number of actual test samples, increasing the efficiency of the experiment.

scholarly journals MATHEMATICAL SUBSTANTIATION OF THE USE OF DIFFERENT TYPES OF CLAMMERS DURING THE RESTORATION OF THE DENTITION WITH DOUBLE-SIDED DISTAL DEFECTS AND THE DEFECT INCLUDED IN THE FRONTAL AREA BY REMOVABLE PROSTHETICS

2019 ◽  
Vol 23 (1-2) ◽  
pp. 13-16
Author(s):  
R.V. Kozak ◽  
D.M. Korol
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Strain State ◽  
Element Model ◽  
Stress Strain ◽  
Equivalent Stresses ◽  
Periodontal Tissues ◽  
Stress Strain State ◽  
Removable Denture ◽  
Periodontal Ligaments

The basic conditions that ensure good functional qualities and durability of prosthetic structures from the point of view of biomechanics, undoubtedly include an optimal way of fixing a partial removable prosthesis, which consists in the correct choice of the clamping system that ensures reliable fixation of the prosthesis in the given position and at the same time causing a minimum of harm supporting teeth, as well as the most rational distribution of occlusal loads transmitted to the supporting tissues, since it is these factors that determine the durability functioning dentures. The purpose of biomechanical studies is to analyze the stress-strain state of the supporting teeth of partial removable prostheses replacing the included and terminal defects of the dentition when fixing the prosthesis on the supporting teeth with the help of holding and supporting-retaining clamps. The studies were performed on a model of the mandible with overall dimensions of the cross section corresponding to some average dimensions. The first volumetric finite element model was developed to study the stress-strain state of periodontal ligaments of supporting teeth and supporting gingival tissues when the incomplete and bilaterial end defects of the dentition were replaced (1 class 1 subclass by Kennedy) of the mandible by a removable denture with fixation by retaining clamps on the canines and the first premolars. The second volumetric finite element model is designed to study the stress-strain state of periodontal ligaments of supporting teeth and supporting gum tissues when the included and two-sided end defects of the dentition of the lower jaw are replaced by a removable clasp prosthesis with fixation of support-retaining clamps on canines and first premolars with support arms of clamps from the distal sides of premolars. As a result of the studies performed, the following conclusions can be drawn: In both considered variants fixation of removable clasp prostheses loaded with maximum values of equivalent stresses in the periodontium of the supporting teeth is localized at the apex of the alveolar ridge, which indicates the transfer of the "clutching" supporting teeth of the clasp prosthesis. The maximum values f equivalent stresses in the periodontitis of the supporting teeth during fixation of the removable clasp prosthesis by the support-retaining clamps on the canines and the first premolars exceed the corresponding values of the equivalent stresses for the case of fixing the prosthesis with retention clamps by 30-140%! With an increase in gum compliance, the values of equivalent stresses in the periodontitis of the supporting teeth during fixation of the removable clasp prosthesis by the retaining clasps vary insignificantly within 25%, and an increase in the corresponding equivalent stresses with the use of support-holding clasps may be 65%. In order to ensure the maximum sparing regimen of periodontal tissues of supporting teeth and as a result - the possibility of the most prolonged use of the prosthesis without loosening of the supporting teeth, it seems more expedient to give preference to the use of clasp prostheses with the fixation of the retaining clasps.

scholarly journals Determining thermal stresses in asphalt concrete by the method of computer simulation

2021 ◽  
pp. 105-111
Author(s):  
Volodymyr Maliar
Keyword(s):  
Finite Element Analysis ◽  
Computer Simulation ◽  
Finite Element ◽  
Asphalt Concrete ◽  
Strain State ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Stress Strain ◽  
Element Analysis ◽  
Stress Strain State

The main destructions of asphalt concrete pavement are rut, transverse cracking, fatigue failures, peeling, etc. When the pavement cools, lowtemperature damages can occur for various reasons. The sources of damages that cause such failures are not well studied, so this problem is relevant. Goal. The aim of this work was to determine the stress-strain state inside the volume of asphalt con-crete during cooling on the basis of a two composite three-dimensional model using the method of computer simulation in response to the changing structured bitumen properties. Methodology. The method of finite element analysis of the stress-strain state of the composite material was used. The material is represented by a three-dimensional (3D) model pro-posed by prof. B.S. Radovsky. Results. The finite element analysis method was used to calculate the average thermal stresses in asphalt concrete during cooling in accordance with increase of viscosity of bitumen section, which is located in asphalt concrete in a structured state. This consideration is realized on the basis of changes in a number of bitumen properties in the contact zone, in particular, the changes in the glass transition temperature. It is shown that the thermal stresses that occur during cooling by limiting the movement of asphalt concrete in the construction reach the strength values at negative temperatures, which can be used to estimate the temperature of crack formation in asphalt concrete under the condi-tion of its action in pavement (Tcr). The values of these stresses depend on the cooling rate, the bitumen content, its viscosity and structure. Originality. For the first time, it was found numerically that in the sample of asphalt concrete, which is free from restriction of movements, there are internal thermal stresses during cooling due to the difference of bitumen thermal expansion coefficients and stone materials. These stresses are up to 87 percent of the average thermal stresses that occur in the compressed sample. Practical value. The possibility of rapid estimation of thermal stresses with the possibility of predicting low-temperature cracks in asphalt concrete is shown.

Simulation of the Stress-Strain State of Diesel Engine Pistons Taking into Account Inelastic Deformations

2020 ◽  
pp. 29-36
Author(s):  
L.L. Myagkov ◽  
S.M. Sivachev
Keyword(s):  
Finite Element ◽  
Diesel Engines ◽  
Strain State ◽  
Low Frequency ◽  
Uniaxial Tensile ◽  
Creep Tests ◽  
Stress Strain ◽  
Element Analysis ◽  
Stress Strain State ◽  
Creep Models

The failure of aluminum pistons of diesel engines is often associated with formation of cracks originating at the bowl rim. The appearance of cracks is a consequence of thermal fatigue of the material due to low-frequency cycles of heating and cooling of the piston during the engine start-up, operation at various speed and load conditions, and subsequent shutdown. To assess the lifetime of the bowl rim, it is necessary to simulate non-isothermal elastoplastic deformation of the alloy using material plasticity and creep models available in finite element analysis software (e.g. ANSYS). This paper presents the results of uniaxial tensile and creep tests of proportional specimens made from piston blanks of the V-type diesel engines YaMZ-658. The piston material is AlSi12CuNiMg silumin alloy. The article describes methods for determining constants in plasticity and creep models. The results of numerical simulation of the piston’s stress-strain state for the start — nominal power mode — stop cycle using the finite element method are presented. Conclusions about the presence of plastic and creep strains at the piston edge are drawn.

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