Improved Finite Element Model to Predict the Reverse Loading Behavior of Autofrettaged A723 and HB7 Cylinders

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
E. Troiano ◽  
J. H. Underwood ◽  
A. M. Venter ◽  
J. H. Izzo ◽  
J. M. Norray
Keyword(s):  
Finite Element ◽  
Bauschinger Effect ◽  
Kinematic Hardening ◽  
Element Model ◽  
Significant Error ◽  
Strain Hardening Exponent ◽  
Element Analysis ◽  
Strong Function ◽  
Reverse Loading ◽  
Loss Of Strength

Ideal isotropic or kinematic hardening is often utilized in order to simplify the modeling of the loading and reverse loading behavior of materials when using finite element analysis. Unfortunately, this simplification can result in significant error if the material exhibits the Bauschinger effect (BE), which is the loss of strength of the material upon reverse loading. The error associated with this simplification is further compounded in heavily autofrettaged, Cr-Mo-V, thick walled cylinders due to the fact that the Bauschinger effect and the reverse loading strain hardening exponent are a strong function of the initial applied plastic strains, which can vary significantly throughout the wall of the cylinder.

scholarly journals Finite Element Analysis on Ultrasonic Drawing Process of Fine Titanium Wire

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 575
Author(s):  
Shen Liu ◽  
Xiaobiao Shan ◽  
Hengqiang Cao ◽  
Tao Xie
Keyword(s):  
Finite Element ◽  
Kinematic Hardening ◽  
New Technology ◽  
Friction Stress ◽  
Element Model ◽  
Underlying Mechanism ◽  
Drawing Process ◽  
Drawing Force ◽  
Element Analysis ◽  
Half Wavelength

Ultrasonic drawing is a new technology to reduce the cross-section of a metallic tube, wire or rod by pulling through vibrating dies. The addition of ultrasound is beneficial for reducing the drawing force and enhancing the surface finish of the drawn wire, but the underlying mechanism has not been fully understood. In this paper, an axisymmetric finite element model of the single-pass ultrasonic drawing was established in commercial FEM software based on actual wire length. The multi-linear kinematic hardening (MKINH) model was used to define the elastic and plastic characteristics of titanium. Influences of ultrasonic vibration on the drawing process were investigated in terms of four factors: location of the die, ultrasonic amplitude, drawing velocity, and friction coefficient within the wire-die contact zone. Mises stresses, as well as contact and friction stress, in conventional and ultrasonic drawing conditions, were compared. The results show that larger ultrasonic amplitude and lower drawing velocity contribute to greater drawing force reduction, which agrees with former research. However, their effectiveness is further influenced by the location of the die. When ultrasonic amplitude and drawing speed remain unchanged, the drawing force is minimized when the die locates at the half-wavelength position, while maximized at the quarter-wavelength position.

Material Models for the Finite Element Analysis of Materials Exhibiting a Pronounced Bauschinger Effect

2006 ◽  
Vol 128 (2) ◽  
pp. 190-195 ◽  
Author(s):  
Rolf R. de Swardt
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Strain Hardening ◽  
Bauschinger Effect ◽  
Element Analysis ◽  
Material Models ◽  
Reverse Loading ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Reverse Yielding

Realistic material models have been developed on the basis of the experimental investigation of reverse loading with actual Bauschinger effect and implemented into a two-dimensional finite element computer program. The developed program is capable of treating the elastoplastic deformation behavior of thick-walled cylinders during both loading and unloading phases. Strain hardening may occur during loading, and reverse yielding may occur during unloading at a yield strength significantly reduced due to the Bauschinger effect. Three different models for the reverse hardening are presented. Strain hardening during reverse yielding may have a different slope than for forward loading, and it may also be nonlinear. The intended application is for autofrettage analysis of thick-walled cylinders. Being a numerical solution, it will also be very useful for finite element analysis of residual stress experimental procedures and also in the determination of more accurate stress intensity factors for autofrettaged cylinders that had undergone reverse yielding due to the Bauschinger effect.

3D Finite Element Modeling of the Swage Autofrettage Process Including the Bauschinger Effect

2007 ◽  
Author(s):  
E. Troiano ◽  
J. H. Underwood ◽  
R. R. de Swardt ◽  
A. M. Venter ◽  
A. P. Parker ◽  
...  
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Pressure Vessel ◽  
Bauschinger Effect ◽  
Three Dimensional ◽  
Element Model ◽  
Pressure Vessels ◽  
Reverse Loading ◽  
Inherent Nature ◽  
Materials Used

The autofrettage process is a method that produces tensile plastic deformation during the overloading of a pressure vessel which reverses and becomes compressive during unloading. This process produces favorable compressive residual hoop stresses at the bore of the pressure vessel, and results in an increase in the life of the component. In thick walled pressure vessels this process can be accomplished with either a hydraulic or mechanical overloading process. These processes produce different residual stress fields by their inherent nature. The Bauschinger effect, which is observed in most of the materials used in thick walled pressure vessels, is a phenomenon which results in lower reverse loading stresses than those predicted with the classic techniques of Hill and others. The phenomenon is a strong function of the amount of plastic strain during the initial loading of the pressure vessel and results in losses of reverse loading strength of up to 40% in A723 and HB7 steels. A quasi-static three dimensional axi-symmetric finite element model of the swage mandrel autofrettage process of a thick walled pressure vessel is presented in this work. It includes the results of several methodologies for predicting the reduced reverse loading stresses resulting from the Bauschinger effect. The FE results are then shown to compare favorably with neutron diffraction residual stress measurements and yield pressure tests.

Finite Element Analysis of Rolling Contact for Nonlinear Kinematic Hardening Bearing Steel

1995 ◽  
Vol 117 (4) ◽  
pp. 729-736 ◽  
Author(s):  
M. Howell ◽  
G. T. Hahn ◽  
C. A. Rubin ◽  
D. L. McDowell
Keyword(s):  
Finite Element ◽  
Kinematic Hardening ◽  
Element Model ◽  
Bearing Steel ◽  
Rolling Contact ◽  
Image Point ◽  
Element Analysis ◽  
Transient Region ◽  
Pure Rolling ◽  
Constitutive Properties

A Mroz image point, two surface, nonlinear-kinematic-hardening-plastic (MNKP) representation of bearing steel is inserted into a finite element model of 2-dimensional, line contact for pure rolling. The calculations are compared with previous results for the same contact pressure derived for elastic-linear-kinematic-hardening-plastic (ELKP) behavior. The residual stress, deformation, and the connection between continuing cyclic deformation, etching bands, and cracks are analyzed. Unlike the ELKP constitutive properties, the MNKP behavior displays a distinct transient region which results in higher residual stresses.

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.

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.

Torsional Analysis of a Steel Cord-Rubber Tire Belt Structure

1996 ◽  
Vol 24 (4) ◽  
pp. 339-348 ◽  
Author(s):  
R. M. V. Pidaparti
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Composite Structures ◽  
Three Dimensional ◽  
Element Model ◽  
Torsional Stiffness ◽  
Element Analysis ◽  
Rubber Belt ◽  
Steel Cord ◽  
Torsional Analysis

Abstract A three-dimensional (3D) beam finite element model was developed to investigate the torsional stiffness of a twisted steel-reinforced cord-rubber belt structure. The present 3D beam element takes into account the coupled extension, bending, and twisting deformations characteristic of the complex behavior of cord-rubber composite structures. The extension-twisting coupling due to the twisted nature of the cords was also considered in the finite element model. The results of torsional stiffness obtained from the finite element analysis for twisted cords and the two-ply steel cord-rubber belt structure are compared to the experimental data and other alternate solutions available in the literature. The effects of cord orientation, anisotropy, and rubber core surrounding the twisted cords on the torsional stiffness properties are presented and discussed.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.

Finite Element Analysis of Tire/Rim Interface Forces Under Braking and Cornering Loads

1992 ◽  
Vol 20 (2) ◽  
pp. 83-105 ◽  
Author(s):  
J. P. Jeusette ◽  
M. Theves
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Contact Pressure ◽  
Element Model ◽  
Shear Stresses ◽  
Detailed Knowledge ◽  
Stress Distributions ◽  
Element Analysis ◽  
Plane Shear ◽  
Normal Contact

Abstract During vehicle braking and cornering, the tire's footprint region may see high normal contact pressures and in-plane shear stresses. The corresponding resultant forces and moments are transferred to the wheel. The optimal design of the tire bead area and the wheel requires a detailed knowledge of the contact pressure and shear stress distributions at the tire/rim interface. In this study, the forces and moments obtained from the simulation of a vehicle in stationary braking/cornering conditions are applied to a quasi-static braking/cornering tire finite element model. Detailed contact pressure and shear stress distributions at the tire/rim interface are computed for heavy braking and cornering maneuvers.

Redrawing Operation a Star Shape from Cylindrical Shape Using Experimental and FE Analysis

2020 ◽  
Vol 38 (1A) ◽  
pp. 25-32
Author(s):  
Waleed Kh. Jawad ◽  
Ali T. Ikal
Keyword(s):  
Finite Element ◽  
Effective Strain ◽  
Element Model ◽  
Cylindrical Shape ◽  
Element Analysis ◽  
Punch Force ◽  
Maximum Value ◽  
Element Simulation ◽  
Blank Sheet ◽  
The Finite Element Model

The aim of this paper is to design and fabricate a star die and a cylindrical die to produce a star shape by redrawing the cylindrical shape and comparing it to the conventional method of producing a star cup drawn from the circular blank sheet using experimental (EXP) and finite element simulation (FES). The redrawing and drawing process was done to produce a star cup with the dimension of (41.5 × 34.69mm), and (30 mm). The finite element model is performed via mechanical APDL ANSYS18.0 to modulate the redrawing and drawing operation. The results of finite element analysis were compared with the experimental results and it is found that the maximum punch force (39.12KN) recorded with the production of a star shape drawn from the circular blank sheet when comparing the punch force (32.33 KN) recorded when redrawing the cylindrical shape into a star shape. This is due to the exposure of the cup produced drawn from the blank to the highest tensile stress. The highest value of the effective stress (709MPa) and effective strain (0.751) recorded with the star shape drawn from a circular blank sheet. The maximum value of lamination (8.707%) is recorded at the cup curling (the concave area) with the first method compared to the maximum value of lamination (5.822%) recorded at the cup curling (the concave area) with the second method because of this exposure to the highest concentration of stresses. The best distribution of thickness, strains, and stresses when producing a star shape by

Sign in / Sign up

Export Citation Format

Share Document