scholarly journals DETERMINISTIC ANALYTICAL MODEL OF RESISTANCE TO DEEP CONTACT FATIGUE OF A STRESSED MATERIAL

2021 ◽  
Vol 3 (56) ◽  
pp. 52-60
Author(s):  
Sergei P. RUDENKO ◽  
◽  
Sergei G. SANDOMIRSKI ◽  
Keyword(s):  
Surface Layer ◽  
Stress State ◽  
Analytical Model ◽  
Structural Characteristics ◽  
Contact Fatigue ◽  
Contact Stresses ◽  
Radius Of Curvature ◽  
Tangential Stresses ◽  
Surface Contact ◽  
Tooth Surfaces

The stress state of the surface layer in the contact zone of the mating teeth of cylindrical gears is considered. It is shown that under contact loading, the stress state of the surface layer is inhomogeneous and changes with the distance from the surface. It is established that the value of the equivalent tangential stresses does not depend on the standard size of the gears, but is determined by the surface contact stresses σH. Moreover, the depth of occurrence of the maximum equivalent tangential stresses depends on the gear modulus (the reduced radius of curvature of the mating surfaces of the teeth) and, to a lesser extent, on the surface contact stresses σH. The inhomogeneity of the stress state and the structural characteristics of the diffusion layers of surface-hardened gears is a prerequisite for the appearance of critical zones in them, in which fatigue processes of contact failure can originate and develop. A deterministic analytical model of the resistance to deep contact fatigue of hardened tooth surfaces is proposed, based on determining the service life of the gear before the appearance of progressive deep contact chipping of the active tooth surfaces with a regulated variation of the microhardness values in different zones of the diffusion layer.

Calculation of Stress-Strain State and Contact Stresses in the Process of Chip Formation

2021 ◽  
Vol 313 ◽  
pp. 59-65
Author(s):  
A.V. Proskokov ◽  
A.S. Yanyushkin
Keyword(s):  
Stress State ◽  
Plastic Zone ◽  
Chip Formation ◽  
Strain State ◽  
Plane Stress State ◽  
Contact Stresses ◽  
Field Pattern ◽  
Plasticity Zone ◽  
Calculation Data ◽  
Tangential Stresses

The reported paper presents a field pattern of sliding lines in a plastic zone of flow chip formation in the process of cutting metals considered for front and rear angles on the cutting blade other than zero. Equations of sliding lines for these conditions are proposed. Using calculation data, plasticity zone border lines are plotted for positive and negative front angles. The paper suggests methods and calculation data on average stress and plane stress state components in nodal points of the plastic zone of chip formation. The study provides data for plotting distribution diagrams of normal and tangential stresses of contact stresses on work surfaces of a cutting blade.

Stresses in the Surface Layer and Hydrogen Absorption and Diffusion in Cavitation Condition

2014 ◽  
Vol 225 ◽  
pp. 131-138
Author(s):  
Jarosław Chmiel ◽  
Jolanta Baranowska ◽  
Roman Jędrzejewski ◽  
Arkadiusz Rzeczycki
Keyword(s):  
Surface Layer ◽  
Stress State ◽  
Hydrogen Absorption ◽  
Surface Layers ◽  
Fem Modeling ◽  
And Diffusion

Cavitation attack in liquids generated a various states of stresses in surface layers of metals. Differences in stress state effects on hydrogen absorption activated by the cavitation implosion. Results of XRD investigation and FEM modeling shows on inhomogenity of process.

Surface contact fatigue failures in gears

1997 ◽  
Vol 4 (2) ◽  
pp. 99-107 ◽  
Author(s):  
P.J.L. Fernandes ◽  
C. McDuling
Keyword(s):  
Contact Fatigue ◽  
Surface Contact ◽  
Fatigue Failures

Analytical and Numerical Prediction of Springback of SS/Al-Alloy Cladded Sheet in V-Bending

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Pankaj Kumar Sharma ◽  
Vijay Gautam ◽  
Atul Kumar Agrawal
Keyword(s):  
Analytical Model ◽  
Outer Layer ◽  
Numerical Models ◽  
Yield Criterion ◽  
Bending Moment ◽  
Analytical Models ◽  
Bend Angle ◽  
Radius Of Curvature ◽  
Al Alloy ◽  
First Case

Abstract The present work deals with the development of an analytical model incorporating the effects of anisotropy and strain hardening to predict the springback in V-bending of two-ply sheet metal using a punch profile radius of 15 mm and included a bend angle of 90 deg. In the analytical model, the total bending moment is determined from resulting bending stresses for two different layers arranged in parallel planes one above the other and a new radius of curvature after springback is determined by applying a negative bending moment. The two-ply sheet composed of layers of AA1050 and SS430 is characterized for its tensile properties to be used in analytical and numerical models for prediction of springback. To study the effect of each layer during bending operation, two possible cases of sheet placements during bending and springback are studied; i.e., in the first case, the inner layer is of AA1050 while the SS430 layer is the outer layer whereas in the second case it is opposite. In all the cases of springback experiments when the outer layer is of SS430, the springback values are higher than the values obtained with the specimens when the inner layer is of SS430. This could be attributed to the higher tensile strength of the stainless steel layer and the higher bending radius experienced by it. The springback behaviors are also analyzed by simulations using Hill's anisotropic yield criterion in abaqus software. The springback results obtained by simulations and analytical models are in good agreement in general; however, in some cases, discrepancy of more than 15% is observed in the analytical results when compared with the experimental results.

scholarly journals Contact stresses in point frogs

2020 ◽  
Vol 164 ◽  
pp. 03034
Author(s):  
Boris Glusberg ◽  
Vadim Korolev ◽  
Olga Lokteva ◽  
Irina Shishkina
Keyword(s):  
Stress State ◽  
Contact Stress ◽  
Contact Stresses

The methodology for calculating the contact stress state for various contact types of frogs and wheel is presented. The magnitudes of contact stresses in the frogs can be calculated according to the Hertz-Belyaev method, taking into account certain evaluating factors.

scholarly journals The Effect of Motion Time of a Scots Pine Single Seed on Mobile Optoelectronic Grader Efficiency: A Mathematical Patterning

Inventions ◽  
2019 ◽  
Vol 4 (4) ◽  
pp. 55 ◽  
Author(s):  
Arthur Novikov ◽  
Michael Drapalyuk ◽  
Olga Dornyak ◽  
Vladimir Zelikov ◽  
Vladan Ivetić
Keyword(s):  
Mathematical Modeling ◽  
Scots Pine ◽  
Structural Characteristics ◽  
A Priori ◽  
High Energy ◽  
Radius Of Curvature ◽  
Optical Scheme ◽  
Single Seed ◽  
Research Problems ◽  
Forest Seeds

Research Highlights: Forest owners will be able to solve the problem of testing and selection of viable forest seeds on location and save financial, time, and material resources. The possibility of integrating non-destructive quality control and separation functions in a single portable apparatus is extremely promising. The speed of the contemporary optoelectronic grader is limited by the speed of the slowest component—the mechanical system. Background and Objectives: The technological process of forest seed establishment and design of optoelectronic graders is based on a priori mathematical modeling of structural characteristics, taking into account these criteria. Known models of industrial photoseparators are expensive and have a high energy and material consumption not applicable in the field. Laboratory seed analyzers are characterized by a long time exposure, and the overall size and level of climatic performance do not allow them to be used in the field. Consequently, for small amounts of seed treatment, it is necessary to orient the seeds one by one and ensure clear and rapid coordinated actions of optoelectronic and mechanical systems. The main goal of this research is to increase the efficiency of grading forest seeds by patterning the speed of the mobile device. We will answer the following questions. What are effective geometric parameters for the seed pipe? What factors affect the speed of a single seed’s movement? Materials and Methods: This study is based on mathematical modeling, taking into account the basic principles of mechanics, using MatLab software. Results: A mechanical model of a single Scots pine seed’s motion in different zones of the seed pipe is designed, taking into account air resistance. The effective height of the seed pipe, taking into account the response time of optoelectronic grader systems, is determined. Conclusions: The time and speed of single seed movement through grader systems depends on the seed pipe’s height and radius of curvature. Other things being equal, through the use of the same optical scheme with a microprocessor to solve various problems, the compactness of the photodetector scheme allows, if necessary, to upgrade the grader to solve research problems and for use in forestry.

The Analysis of Finishing Tooling Influence on Contact Fatigue Researched by Profilometer

2013 ◽  
Vol 199 ◽  
pp. 117-122
Author(s):  
Wojciech Labuda ◽  
Adam Charchalis
Keyword(s):  
Surface Roughness ◽  
Surface Layer ◽  
Contact Fatigue ◽  
Roughness Coefficient ◽  
304L Stainless Steel ◽  
Technological Parameters ◽  
Research Results ◽  
Burnishing Process ◽  
Relative Hardness ◽  
Surface Layer Quality

The article presents the research results referring to the analysis of the influence of finish treatment ( lathing, grinding, burnishing) on the contact fatigue of steel applied to marine pump shafts. The research was performed on a roller 40 mm in diameter made of 304L stainless steel. Within the research, the optimalization of burnishing technological parameters was conducted on account of the minimalization of Ra surface roughness coefficient as well as the maximalization of SU degree of surface layer relative hardness [. The multi criteria optimalization conducted by min-max method [ with regard to minimum surface roughness as well as maximum degree of surface layer hardness demonstrated that burnishing process should be carried out at the following technological parameters: burnishing force 1.1 kN, burnishing speed 35 m/min, feed 0.13 mm/rev. In addition, the influence of the burnisher passes number on the surface layer quality was determined [.The paper will present the research results of contact fatigue examination of samples after finish machining.

Influence of titanium carbide particles addition on the forging behaviour of powder metallurgy composite steels

2008 ◽  
Vol 222 (11) ◽  
pp. 1333-1345 ◽  
Author(s):  
V Senthilkumar ◽  
R Narayanasamy
Keyword(s):  
Stress State ◽  
Titanium Carbide ◽  
Deformation Behaviour ◽  
Triaxial Stress ◽  
Cold Forging ◽  
Radius Of Curvature ◽  
Triaxial Stress State ◽  
Aspect Ratios ◽  
Barrel Radius ◽  
Composite Steel

This paper evaluates some of the cold-forging features of composite steel preforms of varying titanium carbide contents during cold upsetting under triaxial stress state conditions. A complete experimental investigation is carried out on composite steel preforms of varying titanium carbide contents, namely, 3%TiC and 4%TiC with different lubricating conditions; namely, graphite and zinc stearate and no lubrication. Cylindrical compacts with aspect ratios of 0.42, 0.67, and 1.0 were prepared, sintered, and upset forged at room temperature. The measured barrel radius of curvature is found to have a circular arc because the above relationship is a straight-line one. A relationship is established between the measured barrel radius and the stress ratio parameters of (σθ/σz), (σz/σm), and (σeff/σz) determined under triaxial stress state conditions for both composite steels of varying titanium carbide content. The effect of titanium carbide particle addition in the composite steel, initial preform geometry, and lubricating conditions on the deformation behaviour has been studied, together with the densification route of the composite steel preforms during the deformation.

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