scholarly journals Research on the elastic–plastic external contact mechanical properties of cylinder

2020 ◽  
Vol 103 (2) ◽  
pp. 003685042092781
Author(s):  
TieNeng Guo ◽  
Xu Hua ◽  
ZhiJie Yan ◽  
Chunsheng Bai
Keyword(s):  
Contact Angle ◽  
Finite Element ◽  
Contact Area ◽  
Contact Stiffness ◽  
Outer Cylinder ◽  
Contact Angles ◽  
Contact Deformation ◽  
Cylinder Radius ◽  
Elastic Plastic ◽  
Plastic Stage

Based on Hertz contact theory, an elastic-plastic contact mechanics model of outer cylinder under different contact angles of axis is proposed. The relationship among contact angle, load and contact deformation, contact stiffness and contact area is established. The finite element method is used to simulate the elastic-plastic contact process of the cylinder. The influence of the load and radius of the cylinder model on the contact deformation and the contact stiffness is compared and analyzed under different contact angles. The error of the analysis results of the finite element and the mechanical model is within 9%. On this basis, the influence of contact deformation, contact area and contact angle on the contact stiffness of the outer cylinder in elastic and plastic stage is explored. The results show that in the stage of elastic and plastic deformation, the amount of contact deformation and contact area increase with the increase of load. The contact stiffness decreases with the increase of contact angle and increases with the increase of cylinder radius. The amount of contact deformation decreases with the increase of cylinder radius, and tends to constant gradually. In the elastic stage, the contact stiffness increases with the increase of load. The contact area decreases with the increase of contact angle and increases with the increase of cylinder radius. In the plastic stage, the contact stiffness is constant with the increase of load, and the contact area is independent of contact angle and cylinder radius.

Finite Element Analysis on Mechanic Behavior of Joints between Elevated Columns and Truss Columns in Substation Frame

2012 ◽  
Vol 256-259 ◽  
pp. 949-953
Author(s):  
An Liang Song ◽  
Hong Dong Ran ◽  
Ming Zhou Su ◽  
Zhen Shan Wang ◽  
Yun Shi
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Design Principle ◽  
Element Analysis ◽  
Fem Model ◽  
Gusset Plate ◽  
Elastic Plastic ◽  
Whole Process ◽  
Prototype Structure ◽  
Plastic Stage

Finite element analysis have been carried out in order to study the mechanical properties of the joints between elevated columns and truss column in substation frame. Firstly, the numerical results and the experimental ones were compared to verify the efficiency of the FEM model. Then, the whole process of elastic-plastic analysis was carried out to the prototype structure. The results show that when the bottom of the elevated column was yielding, the stress of the stiffeners at the joint is small, which can meet the design principle of “strong joint - weak member” criterion. Furthermore, when the structure enters into the elastic-plastic stage, the stress in the upper stiffeners at the horizontal load direction is large and most of them yield, but the stress in the plane gusset plate of the joint is still small.

Elastic-Plastic Contact Analysis of a Sphere and a Rigid Flat

2002 ◽  
Vol 69 (5) ◽  
pp. 657-662 ◽  
Author(s):  
L. Kogut ◽  
I. Etsion
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Contact Pressure ◽  
Contact Zone ◽  
Contact Area ◽  
Large Range ◽  
Element Model ◽  
Contact Interface ◽  
Frictionless Contact ◽  
Elastic Plastic

An elastic-plastic finite element model for the frictionless contact of a deformable sphere pressed by a rigid flat is presented. The evolution of the elastic-plastic contact with increasing interference is analyzed revealing three distinct stages that range from fully elastic through elastic-plastic to fully plastic contact interface. The model provides dimensionless expressions for the contact load, contact area, and mean contact pressure, covering a large range of interference values from yielding inception to fully plastic regime of the spherical contact zone. Comparison with previous elastic-plastic models that were based on some arbitrary assumptions is made showing large differences.

scholarly journals A Finite Element-Based Elastic-Plastic Model for the Contact of Rough Surfaces

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Ali Sepehri ◽  
Kambiz Farhang
Keyword(s):  
Finite Element ◽  
Contact Force ◽  
Contact Area ◽  
Rough Surfaces ◽  
Constitutive Relations ◽  
Element Model ◽  
Tangential Component ◽  
Asperity Contact ◽  
Elastic Plastic ◽  
Force Components

Three-dimensional elastic-plastic contact of two nominally flat rough surfaces is considered. Equations governing the shoulder-shoulder contact of asperities are derived based on the asperity constitutive relations from a finite element model of the elastic-plastic interaction proposed by Kogut and Etsion (2002), in which asperity scale constitutive relations are derived using piecewise approximate functions. An analytical fusion technique is developed to combine the piecewise asperity level constitutive relations. Shoulder-shoulder asperity contact yields a slanted contact force consisting of two components, one in the normal direction and a half-plane tangential component. Statistical summation of the asperity level contact force components and asperity level contact area results in the total contact force and total contact area formulae between two rough surfaces. Approximate equations are developed in closed form for contact force components and contact area.

scholarly journals A New Combined Model for considering the Plasticity Effects in Contacting Asperities

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Mohammad Amini Sarabi ◽  
Parisa Hosseini Tehrani
Keyword(s):  
Surface Roughness ◽  
Contact Area ◽  
Contact Stiffness ◽  
Contact Angles ◽  
Combined Model ◽  
Stick Slip ◽  
Railway Engineering ◽  
Asperity Distribution ◽  
Contact Parameters ◽  
High Contact Pressure

Wheel-rail contact in railway engineering is an important topic. Due to different materials and surface roughness of wheel and rail, the contact characteristics can alter significantly. This article aims to investigate the effects of surface roughness and asperities on the contact parameters such as contact area, contact force, and contact stiffness. The lateral contacts between asperities are assumed to be the general contact condition. Azimuthal and contact angles distributions are assumed to be spherical harmonic distribution. This assumption is compatible with the asperity distribution on the wheel and the rail surfaces. Besides, a new combined model is developed to cover the stick-slip and the plasticity effects in contacting asperities. The results of the presented model offer very good estimations for the asperities contact characteristics, especially at the small-contact area and separation where high-contact pressure and plastic deformation usually exist.

Unloading Process in Elastic-Plastic Contact of a Rough Surface With a Flat

2008 ◽  
Author(s):  
A. Sepehri ◽  
K. Farhang
Keyword(s):  
Finite Element ◽  
Rough Surface ◽  
Contact Force ◽  
Contact Area ◽  
Three Dimensional ◽  
Integral Form ◽  
Real Contact Area ◽  
Elastic Plastic ◽  
Real Contact ◽  
Approximate Equations

Three dimensional elastic-plastic contact of a nominally flat rough surface and a flat is considered. The asperity level Finite Element based constitutive equations relating contact force and real contact area to the interference is used. The statistical summation of asperity interaction during unloading phase is derived in integral form. Approximate equations are found that describe in closed form contact load as a function of mean plane separation during unloading. The approximate equations provide accuracy to within 6 percent for the unload phase of the contact force.

A study of the mechanics of microindentation using finite elements

1992 ◽  
Vol 7 (3) ◽  
pp. 618-626 ◽  
Author(s):  
T.A. Laursen ◽  
J.C. Simo
Keyword(s):  
Thin Film ◽  
Finite Element ◽  
Contact Area ◽  
Contact Stiffness ◽  
Surface Profile ◽  
Critical Examination ◽  
Actual Contact ◽  
Actual Contact Area ◽  
Straight Line ◽  
Film Substrate

In this paper the finite element method is used to explore the mechanics of the microindentation process. In the simulations discussed, aluminum and silicon are investigated both in their bulk forms and in thin film-substrate combinations. Among the quantities readily computed using this approach and given in this paper are hardness (computed using actual contact area), contact stiffness, effective composite modulus, and surface profile under load. Importantly, this investigation builds on previous work by providing a more critical examination of the amount of pileup (or sink-in) around the indenter in the fully loaded configuration, as well as the variation of the actual contact area during indenter withdrawal. A key conclusion of this study is that finite element simulations do not support the widely used assumption of constancy of area during unloading (for either bulk materials or thin film systems). Furthermore, the amount of pileup or sink-in can be appreciable. The implication of these findings is that for many situations the commonly used straight-line extrapolation of a plastic depth may render an estimate for the contact area that is quite distinct from the actual area. This assertion is demonstrated herein through comparison of hardnesses calculated using actual contact area with values calculated using the straight-line extrapolation of plastic depth.

scholarly journals Relationship of Catheter Contact Angle and Contact Force with Contact Area on the Surface of Heart Muscle Tissue in Cardiac Catheter Ablation

2021 ◽  
Author(s):  
Kriengsak Masnok ◽  
Nobuo Watanabe
Keyword(s):  
Contact Angle ◽  
Catheter Ablation ◽  
Contact Force ◽  
Contact Area ◽  
Heart Muscle ◽  
Contact Angles ◽  
Contact Forces ◽  
Logarithmic Function ◽  
Experimental Procedure ◽  
Relationship Of

Abstract Purpose The aims of this study were to develop an experimental procedure for setting the catheter angle with respect to the surface of the heart muscle and the catheter contact force and to investigate the catheter contact area on the heart muscle as a function of catheter contact angle and force. Methods Visualization tests were performed for 5 contact angles (0°, 30°, 45°, 60°, and 90°) and 8 contact forces (2, 4, 6, 10, 15, 20, 30, and 40 gf). Each experiment was repeated 6 times with 2 different commercially available catheter tips. Results The morphology of the contact area was classified into rectangular, circular, ellipsoidal, and semi-ellipsoidal. The correlation between contact force and contact area was a logarithmic function; increasing contact force was associated with increased contact area. At the same contact force, the correlation between contact angle and contact area was inverse; decreasing contact angle was associated with a corresponding increase in contact area. Conclusion Both the catheter contact angle and contact force substantially impact the contact area and morphology in catheter ablation procedures.

scholarly journals The Solution of the Thermal Elastic-Plastic Problem of Turbine Disk by the Incremental Finite Element Method

1985 ◽  
Author(s):  
Sun Jin-Wen ◽  
Ouyang Chang ◽  
Fang Jing-Yan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Load Capacity ◽  
Limit Load ◽  
Turbine Disk ◽  
Fracture Characteristics ◽  
Elastic Plastic ◽  
Loading And Unloading ◽  
Plastic Stage ◽  
Element Method

In this paper, a stress analysis method and a computation program of the solution for the thermal elastic-plastic problem of turbine disk in an aeroengine are presented by incremental finite element method. That method (It is suitable to the axisymmetric disk in the gasturbine, compressor, steam turbine as well) may be used to compute the stress and displacement of turbine disk at its thermal elastic or thermal elastic-plastic stage, its cracking revolving speed and limit load capacity and what part of that enters into the plastic zone first. The method may be used to compute its loading and unloading process, its residual stress and displacement as well. It is important to analyse the strength of the turbine disk and its fracture characteristics.

A comparison investigation of the contact models for contact and vibration features of cylindrical roller bearings

2019 ◽  
Vol 36 (5) ◽  
pp. 1656-1675
Author(s):  
Jing Liu ◽  
Linfeng Wang ◽  
Zhifeng Shi ◽  
Wennian Yu ◽  
Huifang Xiao
Keyword(s):  
Finite Element ◽  
Contact Stress ◽  
Contact Stiffness ◽  
Computational Results ◽  
Contact Deformation ◽  
Calculation Methods ◽  
Fe Method ◽  
Content Type ◽  
Contact Models ◽  
Cylindrical Roller

Purpose The purpose of this study is to investigate the contact models for contact and vibration features of cylindrical roller bearings (CRBs). CRBs are important parts of rotating machinery. The contact deformation between the roller and the raceway is an essential research topic for the CRBs. The contact deformation between the roller and the raceway can greatly affect vibration characteristics and fatigue life of the CRBs. In this investigation, six different methods are adopted to calculate the contact deformation, contact area width and contact stress between the roller and raceways of a CRB. Design/methodology/approach In this paper, the contact deformations and the contact stiffnesses between the roller and the raceway of a CRB obtained by various well-known empirical methods (Lundberg’s, Palmgren’s, Houpert’s, Cheng’s and Hertzian methods) are directly compared with those by the finite element (FE) method. A two degree-of-freedom (2 DOF) dynamic model of the CRB is applied to investigate the effects of the contact stiffness obtained by different line contact deformation calculation methods on the vibration characteristics, such as the root mean square (RMS), the peak to peak (PTP), the crest factor and the kurtosis of the displacement, velocity and acceleration of the inner raceway. Findings The computational results show that different calculation methods for the contact deformations between rollers and raceways have significant effects on the vibrations of the CRB. It is found that that the differences of computational results obtained by Palmgren’s and Lundberg’s models with respect to the FE method are smaller than those by the other three methods, i.e. Houpert’s, Cheng’s and Hertzain models. The amplitude and peak frequency of the frequency response functions from Palmgren’s method are much more similar to those from the finite element method. The above results indicate that Palmgren’s method is a better calculation method for predicting the contact deformations and dynamics of the CRBs. Originality/value This work adopts six different methods to calculate the contact deformation, contact area width and contact stress between the roller and raceways of a CRB. Moreover, a vibration model of a CRB is used to investigate the effect of contact stiffness obtained by the above methods on the vibrations of the CRB. The works can give some guidance for the accurate analytical method for calculating the contact deformations between rollers and raceways and the vibrations of the CRB.

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