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.

scholarly journals Application of optimization to change eigenfrequency of a pinion

Mechanik ◽  
2017 ◽  
Vol 90 (7) ◽  
pp. 588-590
Author(s):  
Jacek Stadnicki ◽  
Michał Głąbek
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Final Stage ◽  
Parametric Optimization ◽  
Natural Frequencies ◽  
Element Model ◽  
The Way

During the final stage of designing a pinion which is exploited at different rotational speeds, it is occasionally necessary to offset natural frequencies from frequencies of excitations. The way of solving this problem by means of parametric optimization of the pinion profile, assuming small changes of its shape, is discussed in the paper. The problem is solved using finite element model with regard to monolithic pinion of an aircraft gear.

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.

Plastic Crushing Behavior of Thin-Walled Spheres

2008 ◽  
Vol 33-37 ◽  
pp. 719-724
Author(s):  
P. Xue ◽  
J.P. He ◽  
Yu Long Li
Keyword(s):  
Numerical Simulation ◽  
Finite Element Method ◽  
Plastic Deformation ◽  
Finite Element ◽  
Deformation Process ◽  
Experimental Result ◽  
Plastic Deformation Process ◽  
Post Buckling ◽  
Thin Walled ◽  
Crushing Behavior

Plastic crushing behavior of thin-walled spheres under various loading cases is studied using Finite Element Method. The entire plastic deformation process is tracked during the post-buckling process. The results are compared with the experimental results reported in literature [13], and very good agreements between the numerical simulation and the experimental result are achieved.

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.

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.

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 Finite element simulation and experimental investigation of cold forward extrusion process

2018 ◽  
Vol 178 ◽  
pp. 02010 ◽  
Author(s):  
Dorin Luca
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Element Model ◽  
Extrusion Process ◽  
The Finite Element Method ◽  
Forward Extrusion ◽  
Real Process ◽  
Element Simulation ◽  
Plastic Deformation Process ◽  
Good Agreement

Extrusion is the plastic deformation process that allows for the highest degree of complexity profiles to be obtained. This paper presents the simulation of a cold forward extrusion process using the finite element method. The results obtained show the stresses, strains and temperatures during the plastic deformation of the material, as well as the stresses and strains in the punch and die. The analysis of the results obtained for different geometric dimensions of the working tools allowed the optimization of the studied extrusion process. In order to validate the finite element model, experiments were carried out with the data acquisition from the real process, which allowed the appreciation that numerical and experimental data are found in a good agreement.

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