Analysis of Contact Stress on Coating Based upon Hertz Theory

2012 ◽  
Vol 155-156 ◽  
pp. 133-137
Author(s):  
Li Ping Wang ◽  
Hao Dong Luo ◽  
Yan Mei Cui
Keyword(s):  
Finite Element Method ◽  
Coating Thickness ◽  
Contact Stresses ◽  
Contact Theory ◽  
Hard Coating ◽  
Thin Coating ◽  
The Finite Element Method ◽  
Hertz Contact ◽  
Hertz Theory ◽  
Mechanics Performance

It is necessary to study the mechanics performance of thin coating, which composite the prerequisite of coating’s application. The contact stresses are important factors for the design of hard coating/substrate because the failure of the hard coating is usually caused by these stresses. The finite element method is applied to simulate the stress of coating with contact load based on Hertz contact theory. The accuracy of model was initially tested in systems without a film. The contact stresses have been calculated based on various coating/substrate modulus ratios and the coating thickness. Results show that coating thickness changes from 1.5um to 3um, the effects of coating/substrate combination is perfect. The research has important guiding significance for the application of coating.

Elastic and Plastic Analysis of Drive Wheel’s Hertz Contact

2012 ◽  
Vol 184-185 ◽  
pp. 188-195
Author(s):  
Jun Jie Zhao ◽  
Hong Qi Tian ◽  
Yue Qing Ren ◽  
Zhai Jun Lu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Carrying Capacity ◽  
Rational Design ◽  
Load Capacity ◽  
Contact Theory ◽  
Line Contact ◽  
The Finite Element Method ◽  
Hertz Contact ◽  
Plastic Analysis

Conventional drive wheel strength check is based on Hertz line contact theory to do the calculation, for security reasons, the design is more conservative,so that there is a certain margin in carrying capacity of the wheel. To address the above issues, this paper analyzes the wheel contact problem for a precise non-linear contact by the finite element method. By comparison of two methods, it verifies that using the finite element is reasonable to deal with these issues, while it provides a reference for the rational design of full load capacity wheels as well.

scholarly journals Analysis of Contact Deformations in Support Systems Using Roller Prisms

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2644
Author(s):  
Krzysztof Nozdrzykowski ◽  
Zenon Grządziel ◽  
Paweł Dunaj
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Contact Theory ◽  
Finite Element Analyses ◽  
The Finite Element Method ◽  
Hertz Contact ◽  
Contact Points ◽  
Calculation Results ◽  
Reaction Forces ◽  
Shaft Journal

This article presents the results of finite element analyses of the influence of reaction forces on stresses and strains at the contact points of the rollers of prism supports with cylindrical surfaces of the main journals of large-sized crankshafts. The analyses of strains and stresses, as well as the depth of their occurrences, in the case of the shaft journal and support rollers were carried out using Hertz contact theory and the finite element method. These calculation results proved to be highly consistent. Additionally, they provide a basis for stating that, in the case under consideration, permanent deformations do not significantly affect the values of the measured geometrical deviations nor the profile forms of the supported main crankshaft journals.

Researches on the Shear Deformation of Joints Domain of Beam-to-Column Connection of Light Steel Structure

2012 ◽  
Vol 256-259 ◽  
pp. 1004-1007
Author(s):  
Xi Bing Hu ◽  
Jian Hua Lu
Keyword(s):  
Finite Element Method ◽  
Shear Deformation ◽  
Design Method ◽  
Steel Structure ◽  
Structure Calculation ◽  
The Finite Element Method ◽  
Mechanics Performance ◽  
Current Design ◽  
Internal Forces ◽  
Complex Parts

The joint domain of beam-to-column connection is very complex parts under loading, which plays an important role in transferring internal forces in light steel structure, such as moment, shear, axial force and so on. Considering the influence of its shear deformation in the structure calculation can help us to reflect the actual mechanics performance and evaluate precisely practical bearing capacity of the structure. According to the actual characteristics of beam-to-column connection, the author established some models of its joint domain, and used the finite element method to analyze and calculate shear deformation of these models. Meanwhile, the author researched the influence of the changes of various parameters to its shear deformation, and provided beneficial suggestions for revising the current design method of light steel structure finally.

Plastic Yield Conditions for Adhesive Contacts

2008 ◽  
Author(s):  
Yu-Chiao Wu ◽  
George G. Adams
Keyword(s):  
Applied Load ◽  
Contact Theory ◽  
Hertz Contact ◽  
Hertz Theory ◽  
Yield Load ◽  
Plastic Yield ◽  
Curve Fit ◽  
Axis Of Symmetry ◽  
Adhesive Contacts ◽  
Yield Conditions

The Hertz contact theory allows the onset of yielding to be predicted for those contacts in which the effect of adhesion can be neglected. However in microscale contacts, such as those which occur in MEMS, yielding will occur for lower loads than predicted by the Hertz theory. For such cases, the JKR, DMT, and Greenwood-Johnson theories extend the Hertz theory to include the effect of adhesion. The present study provides yield conditions for the JKR, DMT, and Greenwood-Johnson theories of adhesion. Attention is first focused on the initiation of yield along the axis of symmetry of the contact. The results show that the critical loads for the three adhesion theories are close together, but differ significantly from that predicted by Hertz. In fact it is possible for yielding to occur due to adhesion alone, without an external applied load. A curve-fit formula is given to express the yield load as a function of an adhesion parameter for different Poisson’s ratios. Results are also obtained for the onset of plastic deformation away from the axis of symmetry using the Greenwood-Johnson theory of adhesion.

Contact Stiffness Calculation and Effects on Rotordynamic of Rod Fastened Rotor

2016 ◽  
Author(s):  
M. Zhuo ◽  
L. H. Yang ◽  
L. Yu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Contact Stiffness ◽  
Bending Moment ◽  
Element Model ◽  
Bending Stiffness ◽  
The Other ◽  
Contact Theory ◽  
Hertz Contact ◽  
Contact Surfaces

Rod fastened rotor is widely used as one kind of structures of gas turbine rotors. Due to its discontinuity, the stiffness of the combined rotor is different from integral rotor. In order to obtain the dynamic of rod fastened rotor, the stiffness of contact needs to be calculated. There are two main methods to calculate the stiffness of contact. One is focus on the microscopic spots in contact based on the fact that maching surface is full of asperities. Hertz contact theory and Greenwood model are used to calculate the contact stiffness under both moment and preload. The other method is finite element method and assumes the contact surfaces are absolutely smooth which is from macroscopic aspect. Contact stiffness is calculated using the two methods and their influencing factors are discussed. Also the contact stiffness from the two methods is used to build a finite element model of a rod fastened rotor and their influences on dynamics of combined rotor are investigated and compared. Results show that the effect of preload of rods on contact stiffness is due to the roughness of contact surfaces. When no separation appears in contact, the bending stiffness is independent of bending moment in both methods. However, it shows a contrary variation when separation appears. Although there is big difference of bending stiffness from both methods, it shows little influence on the rotordynamic of the rod-fastened rotor.

Contact Behaviors of Coated Asperity with Power-Law Hardening Elastic–Plastic Substrate During Loading and Unloading Process

2018 ◽  
Vol 10 (03) ◽  
pp. 1850034 ◽  
Author(s):  
Xiqun Lu ◽  
Fuzhan Huang ◽  
Bin Zhao ◽  
Leon M. Keer
Keyword(s):  
Finite Element Method ◽  
Plastic Deformation ◽  
Finite Element ◽  
Power Law ◽  
Coating Thickness ◽  
Rapid Decrease ◽  
Plastic Substrate ◽  
The Finite Element Method ◽  
Elastic Plastic ◽  
Loading And Unloading

The behavior of a coated asperity contacting with a rigid flat during the loading and unloading processes is investigated using the finite element method. The power-law hardening elastic–plastic substrate is considered, and the effect of the substrate hardening exponent and the coating thickness on the contact behavior is studied. It is shown that in the loading process, the contact load increases more slow and the contact area increases faster as the interference increases for smaller coating thickness and hardening exponent cases, and the coating thickness recovers more obviously after a rapid decrease. In the unloading process, the residual interference and the pileup effect of the asperity surface is larger for smaller coating thicknesses and hardening exponents, and the energy loss due to the plastic deformation is larger accordingly.

Analysis of Stresses and Displacements of Thin Coating Structures

2017 ◽  
Vol 887 ◽  
pp. 41-45
Author(s):  
Elena Sima ◽  
George Bălan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Composite Material ◽  
Organic Polymer ◽  
Constant Thickness ◽  
Thin Coating ◽  
Polymer Fiber ◽  
The Finite Element Method ◽  
Thin Coatings ◽  
Structural Research

This paper addresses the problem of open thin coatings of constant thickness made from Kevlar composite material. Kevlar is an organic polymer fiber 5 times stronger than steel taken at the same weight. Therefore, this fiber has been used successfully in producing composite materials. In this paper, the generic name of Kevlar designates the composite material having the following characteristics: E=7,6×104MPa; θ=0,34; ρ=1700kgcm3. The program COSMOS/M with which the study was conducted and broadcasted was The Structural Research and Analysis Corp. The analysis was carried out by the finite element method.

Finite Element Analysis of Assembly Body of Conical Pick

2013 ◽  
Vol 397-400 ◽  
pp. 573-576
Author(s):  
Xin Zheng Pu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Maximum Stress ◽  
Rock Cutting ◽  
The Finite Element Method ◽  
Maximum Displacement ◽  
Element Analysis ◽  
Conical Pick ◽  
Mechanics Performance

In order to improve the structure mechanics performance of assembly body of conical pick, the finite element method was taken to analyse assembly body of conical pick based on rock cutting theory, and the distortion law of stress and displacement of carbide tip, pick arbor and pick holder were obtained. The results show that the maximum stress appearing in pick carbide tip and its weld site is 371MPa, maximum stress of pick holder appearing in its weld site is 157MPa. Consequently, the quality of the weld should be ensured in processing and manufacturing or welding installation to reduce the performance of carbide tip and pick holder drop. The maximum displacement of assembly body of conical pick is 1.14mm, which has little influence on the structure mechanics performance of assembly body. The research results could provide some guidance for designing, manufacturing or welding the assembly body of conical pick.

Simulation of tuning graphene plasmonic behaviors by ferroelectric domains for self-driven infrared photodetector applications

Nanoscale ◽  
2019 ◽  
Vol 11 (43) ◽  
pp. 20868-20875 ◽  
Author(s):  
Junxiong Guo ◽  
Yu Liu ◽  
Yuan Lin ◽  
Yu Tian ◽  
Jinxing Zhang ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Interfacial Effect ◽  
Infrared Photodetector ◽  
The Finite Element Method ◽  
Ferroelectric Domains ◽  
Element Method

We propose a graphene plasmonic infrared photodetector tuned by ferroelectric domains and investigate the interfacial effect using the finite element method.

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