scholarly journals Effect of the sector radius of a workpiece-deforming tool on the stress-strain state in the contact zone with a cylindrical surface

2022 ◽  
Vol 25 (6) ◽  
pp. 696-707
Author(s):  
S. A. Zaides ◽  
Quan Minh Ho ◽  
Nghia Duc Mai
Keyword(s):  
Surface Layer ◽  
Plastic Zone ◽  
Residual Stresses ◽  
Cylindrical Surface ◽  
Strain State ◽  
Stress Strain ◽  
Stress Strain State ◽  
Cylindrical Workpiece ◽  
Zone Depth ◽  
Depth Ranges

This paper aims to determine the effect of the sector radius of a workpiece-deforming tool on the stress-strain state in the center of elastoplastic deformation and residual stresses in the hardened zone of the surface layer of cylindrical workpieces. A mathematical model of local loading was constructed using the finite element method and AN-SYS software. This model was used to determine the values of temporary and residual stresses and deformations, as well as the depth of plastic zone, depending on the sector radius of the working tool. The simulation results showed that, under the same loading of a cylindrical surface, working tools with different sector radii create different maximum tempo-rary and residual stresses. An assessment of the stress state was carried out for situations when the surface layer of a product is treated by workpiece-deforming tools with a different shape of the working edge. It was shown that, compared to a flat tool, a decrease in the radius of the working sector from 125 to 25 mm leads to an increase in the maximum temporary and residual stresses by 1.2–1.5 times, while the plastic zone depth increases by 1.5–2.4 times. The use of a working tool with a flat surface for hardening a cylindrical workpiece ensures minimal temporary residual stresses, com-pared to those produced by a working tool with a curved surface. A decrease in the radius of the working sector leads to an increase in temporary residual stresses by 2–7%. The plastic zone depth ranges from 1.65 to 2.55 mm when chang-ing the sector radius of the working tool.

Method of Investigation of the Stress-Strain State of Surface Layer of Machine Elements from a Sintered Nonuniform Material

2013 ◽  
Vol 486 ◽  
pp. 32-35 ◽  
Author(s):  
Valery V. Kuzin ◽  
Stanislav Grigoriev
Keyword(s):  
Surface Layer ◽  
Strain State ◽  
Automated System ◽  
Linear Expansion Coefficient ◽  
Stress Strain ◽  
Stress Strain State ◽  
Elasticity Problems ◽  
Microstructural Model ◽  
Machine Elements ◽  
Nonuniform Material

A microstructural model of surface layer of machine elements from a nonuniform material is developed. With using of this model a calculation scheme that includes basic structural elements is created. Each element is characterized by the following properties: density, elastic modulus, thermal conductivity, linear expansion coefficient and Poisson's ratio. A mathematical model of surface layer of machine elements from a sintered nonuniform material is formulated on the basis of solution of two-dimensional heat-conduction and elasticity problems by the finite-element method. The created algorithms for solution of these problems are used for formation of an automated system for thermal strength calculations. This system is surrounded with some original techniques which provide the investigation of the stress-strain state of surface layer of machine elements from a sintered nonuniform material.

scholarly journals Modern systems for monitoring the stress-strain state of hazardous power generating facilities

2021 ◽  
Vol 263 ◽  
pp. 02008
Author(s):  
Anatoly Zemlyansky ◽  
Alexander Zhukov ◽  
Daria Bulavina
Keyword(s):  
Residual Stresses ◽  
Construction Industry ◽  
Strain State ◽  
State Level ◽  
Operational Reliability ◽  
Building Structures ◽  
Stress Strain ◽  
Factors Affecting ◽  
Stress Strain State ◽  
Dominant Direction

The paper considers the issue of effectively increasing the level of operational reliability of power generating nuclear and hydraulic facilities. Over the past 20 years, the number of accidents at these facilities has been growing. There are many factors affecting the collapse of structures, but, according to the authors, the lack of a monitoring system capable of fully assessing not only the stress-strain state, but also the so- called “residual” stresses of the material is the dominant direction of research. The same question is raised at the state level, as evidenced by the requirements of the STO, GOST and Federal laws, to which the authors refer below. The legislative prerequisites (requirements) for the creation of an improved system for monitoring critical structures, corresponding to the development trends of the construction industry, as well as the modernization of the existing fund are listed. The drawbacks and advantages of existing monitoring systems (strain gauge, string, fiber-optic sensors and acoustic emission systems) are analyzed in detail, and the general lack of the possibility of measuring, evaluating "residual" stresses in the material of structures is noted. A fundamentally new system for monitoring the stress-strain state of building structures and power equipment is proposed, which is based on the Foerster effect, a comparison is made with the existing systems described above. The main features and capabilities of the method are noted and options for use at highly important facilities are proposed.

Thermal analysis of stress-strain state of surface layer of ground Si3N4‒TiC ceramics

2021 ◽  
pp. 61-68
Author(s):  
V. V. Kuzin ◽  
S. N. Grigor’ev ◽  
M. A. Volosova
Keyword(s):  
Thermal Analysis ◽  
Surface Layer ◽  
Strain State ◽  
Stress Strain ◽  
Stress Strain State

С использованием базовых положений компьютерной инженерии изучено тепловое и напряженное состояние поверхностного слоя шлифованной Si3N4‒TiC-керамики четырех систем под действием теплового потока. Установлены закономерности распределения температур и напряжений в шести выделенных поверхностях поверхностного слоя. Определена специфика формирования структурной неоднородности напряжений и микроструктурных концентраторов напряжений, приводящих к изменению структуры керамики за счет образования несплошностей.

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