Contribution of Surface Irregularities to Rolling Contact Plasticity in Bearing Steels

1995 ◽  
Vol 117 (4) ◽  
pp. 660-666 ◽  
Author(s):  
V. Gupta ◽  
G. T. Hahn ◽  
P. C. Bastias ◽  
C. A. Rubin
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Finite Element Model ◽  
Half Space ◽  
Kinematic Hardening ◽  
Constitutive Relations ◽  
Element Model ◽  
Bearing Steels ◽  
Deep Groove ◽  
Surface Irregularities

A “two-body” elasto-plastic finite element model of two-dimensional rolling and rolling-plus-sliding has been developed to treat the effect of surface irregularities. The model consists of a smooth cylinder in contact with a semi-infinite half-space that is either smooth or fitted with one of two irregularities: a 0.4 μm deep groove, or a 7 μm deep groove. The model incorporates elastic-linear-kinematic-hardening-plastic (ELKP) and nonlinear-kinematic-hardening-plastic (NLKP) material constitutive relations appropriate for hardened bearing steel and the 440C grade. The calculated contact pressure distribution is Hertzian for smooth body contact, and it displays intense, stationary, pressure spikes superposed on the Hertzian pressure for contact with the grooved and ridged surface. The results obtained for the 0.4 μm deep groove are consistent with those reported by Elsharkawy and Hamrock (1991) for an EHD lubricated contact. The effect of translating the counterface on the half space, as opposed to indenting the counterface on the half-space with no translation, is studied. The stress and strain values near the surface are found to be similar for the two cases, whereas they are significantly different in the subsurface. Efforts have been made to identify the material constitutive relations which best describe the deformation characteristics of the bearing steels in the initial few cycles. ELKP material constitutive relations produce less net plastic deformation in the initial stages, for a given stress, than seen in experiments. NLKP model produces more plasticity than the ELKP model and shows promise for treating the net distortions in the early stages. Artificial indents were inserted on the running track of the cylindrical rolling elements and profilometer measurements of these indents were made, before and after rolling. These preliminary measurements show that substantial plastic deformation takes place in the process of rolling. The deformations of the groove calculated with the finite element model are compared to those measured experimentally.

A SPECTRAL/hp NONLINEAR FINITE ELEMENT ANALYSIS OF HIGHER-ORDER BEAM THEORY WITH VISCOELASTICITY

2012 ◽  
Vol 04 (01) ◽  
pp. 1250010 ◽  
Author(s):  
V. P. VALLALA ◽  
G. S. PAYETTE ◽  
J. N. REDDY
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Virtual Work ◽  
Constitutive Relations ◽  
Beam Theory ◽  
Element Model ◽  
Higher Order ◽  
Time Step ◽  
Third Order ◽  
The Third

In this paper, a finite element model for efficient nonlinear analysis of the mechanical response of viscoelastic beams is presented. The principle of virtual work is utilized in conjunction with the third-order beam theory to develop displacement-based, weak-form Galerkin finite element model for both quasi-static and fully-transient analysis. The displacement field is assumed such that the third-order beam theory admits C0 Lagrange interpolation of all dependent variables and the constitutive equation can be that of an isotropic material. Also, higher-order interpolation functions of spectral/hp type are employed to efficiently eliminate numerical locking. The mechanical properties are considered to be linear viscoelastic while the beam may undergo von Kármán nonlinear geometric deformations. The constitutive equations are modeled using Prony exponential series with general n-parameter Kelvin chain as its mechanical analogy for quasi-static cases and a simple two-element Maxwell model for dynamic cases. The fully discretized finite element equations are obtained by approximating the convolution integrals from the viscous part of the constitutive relations using a trapezoidal rule. A two-point recurrence scheme is developed that uses the approximation of relaxation moduli with Prony series. This necessitates the data storage for only the last time step and not for the entire deformation history.

scholarly journals Engineering our Favorite Pastime

2010 ◽  
Vol 132 (04) ◽  
pp. 44-48
Author(s):  
Lloyd Smith ◽  
James Sherwood
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Finite Element Model ◽  
Failure Modes ◽  
Element Model ◽  
Layer By Layer ◽  
Ball Impact ◽  
Support Mechanism ◽  
Bat Performance ◽  
Technology Advances

This article describes the equipment and technology advances in baseball and softball games. Research efforts are currently being pursued by the authors to develop a layer-by-layer finite element model of a baseball. While work on improved ball models is ongoing, a number of significant accomplishments have been made with current models. These include comparing bat performance, describing the plastic deformation (denting) observed in metal bats, and the failure modes observed with wood bats. To simulate the bat/ball impact at game-like speeds, a durability machine is used to fire balls at a bat at speeds up to 200 mph, at the rate of 10 per minute. After a ball is shot, it falls into a trough and is loaded back into the magazine, which holds up to 36 balls. The bat-support mechanism simulates the grip and flexibility of a batter and can be programmed to rotate the bat between hits to simulate the use of hollow bats or to remain “label up” as is needed for wood bats.

A Finite Element Model for Spherical Debris Denting in Heavily Loaded Contacts

2004 ◽  
Vol 126 (1) ◽  
pp. 71-80 ◽  
Author(s):  
Young Sup Kang ◽  
Farshid Sadeghi ◽  
Mike R. Hoeprich
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Friction Coefficient ◽  
Aspect Ratio ◽  
Finite Element Model ◽  
Contact Force ◽  
Material Properties ◽  
Element Model ◽  
Friction Coefficients ◽  
Elastic Plastic

The objective of this study is to develop models to investigate the effects of contaminants (debris denting process) in heavily loaded rolling and sliding contacts. A dynamic time dependent finite element model (FEM) was developed to determine the elastic-plastic deformation and contact force generated between the mating surfaces and a spherical debris as debris passes through the contact region. The FEA model was used to obtain the effects of various parameters such as debris sizes, material properties, friction coefficients, applied loads, and surface speeds on the elastic-plastic deformation and contact force of the system. The FEM was used to predict debris and mating surfaces deformations as a function of debris size, material properties, friction coefficient, applied load, and surface speed. Using the FEM, a parametric study demonstrated that material properties (i.e., modulus of elasticity, yield strength, ultimate strength and Poisson’s ratio) and friction coefficients play significant roles on the height and width of dents on the mating surfaces. For lower friction coefficients μd<0.3 the debris and mating surfaces slip more easily relative to one another and therefore the debris has lower aspect ratio. As friction coefficient is increased the debris and mating surfaces stick to one another and therefore the debris deforms less and has higher aspect ratio. The results indicate that the pressure generated between the debris and mating surfaces is high enough to plastically deform the debris and mating surfaces and cause a permanent dent on the surfaces and cause residual stresses around the dent. Based on the FEM results, a dry contact model (DCM) was developed to allow similar analyses as the FEM, however, in significantly shorter computational time.

Effects of spall edge profiles on the edge plastic deformation for a roller bearing

2017 ◽  
Vol 233 (5) ◽  
pp. 850-861 ◽  
Author(s):  
Jing Liu ◽  
Zhifeng Shi ◽  
Yimin Shao ◽  
Huifang Xiao
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Finite Element Model ◽  
Deformation Zone ◽  
Element Model ◽  
Plastic Deformation Zone ◽  
Plastic Deformations ◽  
Zone Width ◽  
Rolling Element ◽  
The Finite Element Model

A clear understanding of the plastic deformations at the spall edges is a primary task for the edge propagation predictions in rolling element bearings. This work proposed an elastic–plastic two-dimensional finite element model for calculating the contact stress and plastic deformation between the rolling element and raceway. This model includes a rolling element and one raceway. The rectangular plane strain solid elements are used to formulate the finite element model. The Coulomb model is used to formulate the friction force between the rolling element and raceway. A bilinear kinematic hardening material model is used in the finite element model, which can formulate the elastic–plastic deformations. The studied spall edge profiles are assumed to be sharp and cylindrical ones. To validate the finite element model, the contact deformations between the rolling element and the raceway from the proposed model and Hertzian contact theory are compared. Effects of spall edge profiles on the edge plastic deformations at the edge are analyzed, as well as the edge plastic deformation zone width. Based on the numerical results, the relationship between the edge plastic deformation and the spall edge profile, and that between the edge plastic deformation zone width and the spall edge profile are established. The results show that the edge plastic deformation is significantly influenced by the spall edge profiles, as well as the edge plastic deformation zone width. This paper provides a clear understanding of the effects of the edge profiles on the plastic deformations and propagation at the spall edge.

scholarly journals Effect of Cyclic Loadings on the Shear Strength and Reinforcement Slip of RC Beams

2017 ◽  
Vol 3 (2) ◽  
pp. 111-123 ◽  
Author(s):  
Mohammed A Sakr
Keyword(s):  
Finite Element ◽  
Shear Strength ◽  
Reinforced Concrete ◽  
Finite Element Model ◽  
Failure Mode ◽  
Failure Modes ◽  
Concrete Beams ◽  
Kinematic Hardening ◽  
Element Model ◽  
Reinforced Concrete Beams

Numerous studies of the response of reinforced concrete members under cyclic loadings, many of which have been summarized and have indicated that, in general, the flexural strength of under-reinforced beams remains unimpaired under cyclic loadings consisting of a reasonable number of cycles. However, there is a body of evidence indicating that their shear strength may suffer under such loadings. The first objective of the current study is to construct an accurate 2D shell finite element model of reinforced concrete beams under cyclic loadings. The second objective is carrying out a parametric study on reinforced concrete beams, using the suggested 2D shell model.  The objective of this study was to observe the effect of the stirrup spacing, steel-to-concrete bond properties on the performance of reinforced concrete beams under cyclic loadings. For this purpose, an efficient and accurate finite element model was established taking into account the compression and tensile softening introducing damage in the concrete material, the Baushinger effect using nonlinear isotropic/kinematic hardening in the steel and an adequate bond-slip law for the concrete–steel interface. The simulated results of numerical models were verified by experimental results available in literature in order to validate the proposed model, including hysteretic curves, failure modes, crack pattern and debonding failure mode. The model provided a strong tool for investigating the performances of reinforced concrete beam. The results showed that: Cyclic loadings may change the failure mode of the beam to bond failure even though it has sufficient bond length to resist static loadings. So that under cyclic loadings additional anchorage length must be taken, cyclic loadings also influence the ductility and peak load for beams fail in shear. All these topics are of the utmost importance to RC behaviour to be considered by construction codes.

scholarly journals Vibration analysis of deep groove ball bearing with outer race defect using ABAQUS

2016 ◽  
Vol 35 (4) ◽  
pp. 312-325 ◽  
Author(s):  
A Nabhan ◽  
M Nouby ◽  
AM Sami ◽  
MO Mousa
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Angular Position ◽  
Three Dimensional ◽  
Element Model ◽  
Experimental Results ◽  
Local Defect ◽  
Outer Race ◽  
Deep Groove ◽  
Three Dimensional Finite Element

The main objective of this paper is to determine the effect of outer race defect of deep groove ball bearings for (SKF 6004) through experimental and numerical methods. Three-dimensional finite element model of the housing and outer race is simulated using commercial package ABAQUS/CAE. Angular position of the local defect on the outer race which changes from 0° to 315° with angular intervals 45° is investigated through the dynamic finite element model. Experimental results are obtained using bearing test rig to validate the simulated results. A good agreement is found between the results obtained by the finite element model and the experimental results.

A New Video Extensometer System for Testing Materials Undergoing Severe Plastic Deformation

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
Andrea J. Felling ◽  
Darrel A. Doman
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Severe Plastic Deformation ◽  
Finite Element Model ◽  
Plane Deformation ◽  
Element Model ◽  
Cold Upsetting ◽  
Out Of Plane ◽  
Compressive Testing ◽  
Video Extensometry

Characterization of materials undergoing severe plastic deformation requires the careful measurement of instantaneous sample dimensions throughout testing. For compressive testing, it is insufficient to simply estimate sample diameter from an easily measured height and volume. Not all materials exhibit incompressibility, and friction during testing can lead to a barreled sample with diameter that varies with height. Video extensometry has the potential to greatly improve testing by capturing the full profile of a sample, allowing researchers to account for such effects. Common two-dimensional (2D) video extensometry algorithms require thin, planar samples, as they are unable to account for out-of-plane deformation. They are, therefore, inappropriate for standard compressive tests which use cylindrical samples that exhibit large degrees of out-of-plane deformation. In this paper, a new approach to 2D video extensometry is proposed. By using background subtraction, the profile of a cylindrical sample can be isolated and measured. Calibration experiments show that the proposed system has a 3.1% error on calculating true yield stress—similar to ASTM standard methods for compressive testing. The system is tested against Aluminum 2024-T351 in a series of cold upsetting tests. The results of these tests match very closely with similar tests from the literature. A preliminary finite element model constructed using data from these tests successfully reproduced experimental results. Diameter data from the finite element model undershot, but otherwise closely matched experimental data.

Elastoplastic Finite Element Analysis of Three-Dimensional, Pure Rolling Contact at the Shakedown Limit

1990 ◽  
Vol 57 (1) ◽  
pp. 57-65 ◽  
Author(s):  
S. M. Kulkarni ◽  
G. T. Hahn ◽  
C. A. Rubin ◽  
V. Bhargava
Keyword(s):  
Finite Element ◽  
Half Space ◽  
Kinematic Hardening ◽  
Three Dimensional ◽  
Element Model ◽  
Rolling Contact ◽  
Stress Strain ◽  
Element Analysis ◽  
Perfectly Plastic ◽  
Shakedown Limit

This paper describes a three-dimensional elastoplastic finite element model of repeated, frictionless rolling contact. The model treats a sphere rolling on an elastic-perfectly plastic and an elastic-linear-kinematic-hardening plastic, semi-infinite half space. The calculations are for a relative peak pressure (po/k) = 4.68 (the theoretical shakedown limit for perfect plasticity). Three-dimensional rolling contact is simulated by repeatedly translating a hemispherical (Hertzian) pressure distribution across an elastoplastic semi-infinite half space. The semi-infinite half space is represented by a finite mesh with elastic boundaries. The calculations describe the distortion of the rim, the residual stress-strain distributions, stress-strain histories, and the cyclic plastic strain ranges in the vicinity of the contact.

scholarly journals Influence of Process and Billet Parameters on the Dimensional Accuracy of Hexagonal Pipes During Mandrel Drawing

2021 ◽  
Vol 346 ◽  
pp. 01042
Author(s):  
Evgenii Raskatov ◽  
Anastasia Parshina
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Finite Element Model ◽  
Deformation Process ◽  
Dimensional Accuracy ◽  
Element Model ◽  
Plastic Deformation Process ◽  
The Way

The object of the article is hexagonal profile tubes with a round inner hole. Tubes of such configuration have wide enough application, however the way of their obtaining by drawing in profile tool is insufficiently investigated. The paper is devoted to description of creation of finite element model of plastic deformation process of pipes, the basic computational capabilities of the model are given, a number of conclusions made on the basis of modelling results are given.

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