Elastic Contact Model Accounting for Both Asperity and Substrate Compliance With Application to Patterned Media

2007 ◽  
Author(s):  
Chang-Dong Yeo ◽  
Andreas A. Polycarpou
Keyword(s):  
Bulk Material ◽  
Contact Stiffness ◽  
Contact Model ◽  
Elastic Contact ◽  
Element Analysis ◽  
Patterned Media ◽  
Single Asperity ◽  
Proposed Model ◽  
Stiffness Model ◽  
Bulk Substrate

An improved elastic contact stiffness model for a single asperity system is proposed to account for the effects of both bulk substrate and asperity deformations between two contacting surfaces. Depending upon the applied load, as well as the geometrical and physical properties of the asperity and bulk material, the bulk substrate can have a considerable contribution to the overall contact stiffness. Finite element analysis is performed to verify the proposed analytical model. The single asperity model is extended to rough surfaces in contact. The contact stiffness values from the proposed model are compared to those from the GW model. The proposed contact model can be directly relevant to analyze the contact behavior of modern patterned media.

An Improved Elastic Contact Model Accounting for Asperity Interaction and Bulk Substrate Deformation

2009 ◽  
Author(s):  
Jungkyu Lee ◽  
Chang-Dong Yeo ◽  
Andreas A. Polycarpou
Keyword(s):  
Rough Surface ◽  
Contact Stiffness ◽  
Elastic Half Space ◽  
Contact Model ◽  
Asperity Contact ◽  
Single Asperity ◽  
Surface Contact ◽  
In Series ◽  
Bulk Substrate ◽  
Rough Surface Contact

An improved rough surface contact model is proposed accounting for bulk substrate deformation and asperity interaction. The asperity contact stiffness is based on Hertzian solution for spherical contact, and the bulk substrate stiffness on the solution of Hertzian pressure on a circular region of the elastic half-space. The contact behavior of a single asperity composed of hemi-spherical asperity deformation as well as bulk substrate deformation is calculated by introducing the concept of spring-in-series. Based on the single asperity model, the contact stiffness for the rough surface is calculated including the effect of asperity interaction. Analytical simulation results using the proposed rough surface contact model were compared with the CEB model and experimental measurements.

A New Contact Model of Rough Surface Based on Analytical Method

2018 ◽  
Author(s):  
Yunyun Sun ◽  
Huifang Xiao ◽  
Jinwu Xu
Keyword(s):  
Elastoplastic Deformation ◽  
Polynomial Function ◽  
Contact Stiffness ◽  
Contact Model ◽  
Normal Contact ◽  
Single Asperity ◽  
Proposed Model ◽  
Deformation Regime ◽  
Elliptical Function ◽  
Good Agreement

In this paper, an analytical contact model is proposed to study the contact behavior between two rough surfaces. Elliptical function is employed to describe contact stiffness of a single asperity, and the contact area is characterized by polynomial function in elastoplastic deformation regime. Results show that the proposed model ensures the continuity and smoothness of contact variables across different deformation regimes for a single asperity. The accuracy of the contact model has been demonstrated by the good agreement between the proposed model and the existing statistical model. Influences of material properties on normal contact force and interfacial stiffness have been further studied using the established model.

A modified elastic contact stiffness model considering the deformation of bulk substrate

2020 ◽  
Vol 34 (2) ◽  
pp. 777-790
Author(s):  
Ling Li ◽  
Jingjing Wang ◽  
Xiyong Pei ◽  
Wei Chu ◽  
Anjiang Cai
Keyword(s):  
Contact Stiffness ◽  
Elastic Contact ◽  
Stiffness Model ◽  
Bulk Substrate

Stiffness model of fixed joint considering self-affinity and elastoplasticity of asperities

2019 ◽  
Vol 72 (1) ◽  
pp. 128-135 ◽  
Author(s):  
Hongxu Chen ◽  
Qin Yin ◽  
Guanhua Dong ◽  
Luofeng Xie ◽  
Guofu Yin
Keyword(s):  
Elastic Deformation ◽  
Contact Stiffness ◽  
Roughness Parameter ◽  
Experimental Results ◽  
Content Type ◽  
Elastoplastic Contact ◽  
Proposed Model ◽  
Stiffness Model ◽  
Fractal Roughness ◽  
Deformation Ratio

Purpose The purpose of this paper is to establish a stiffness model of fixed joint considering self-affinity and elastoplasticity of asperities. Design/methodology/approach The proposed model considers that asperities of different scales are interrelated rather than independent. For elastoplastic contact, a spring-damper model and an elastic deformation ratio function were proposed to calculate the contact stiffness of asperities. Findings A revised fractal asperity model was proposed to calculate the contact stiffness of fixed joint, the impacts of the fractal dimension, the fractal roughness parameter and the Meyer index on the contact stiffness were discussed, and the present experimental results and the Jiang’s experimental results showed that the stiffness can be well predicted by proposed model. Originality/value The contradiction between the Majumdar and Bhushan model and the Morag and Etsion model can be well explained by considering the interaction among asperities of different scales. For elastoplastic contact, elastic deformation ratio should be considered, and the stiffness of asperities increases first and then decreases with the increasing of interference.

Rotor Dynamic Analysis of Tie-Bolt Fastened Rotor Based on Elastic-Plastic Contact

2011 ◽  
Author(s):  
He Peng ◽  
Zhansheng Liu ◽  
Guilong Wang ◽  
Min Zhang
Keyword(s):  
Contact Stiffness ◽  
Contact Model ◽  
Elastic Contact ◽  
Critical Speeds ◽  
Elastic Plastic ◽  
Equivalent Bending Stiffness ◽  
The Difference ◽  
Rigid Plane ◽  
Contact Situation ◽  
Rotor Dynamic

The tie-bolt fastened rotor which is assembled by rods distributed circumferentially is modeled and analyzed by finite element method with the consideration of elastic-plastic contact between discs. Based on elastic-plastic contact model between an elastic hemisphere and a rigid plane, the contact between discs is investigated by the statistical contact model of rough surfaces, and the contact stiffness is derived. The equivalent bending stiffness between discs is acquired. With the increase of the load between the two contact surfaces, the difference between the contact stiffness of purely elastic contact and elastic-plastic model is compared. With the obtained contact stiffness, the equation of motion for the tie-bolt fastened rotor system is formed and the critical speeds are calculated. It indicates that the contact stiffness between discs increases as the load increases. The contact stiffness of elastic-plastic contact model is lower than that of the elastic contact model, and the difference between the two models increases with load. With the stiffness of elastic-plastic contact, the critical speeds of tie-bolt fastened rotor are lower than that of the pure elastic contact situation.

A stiffness model for bolted joints considering asperity interactions of rough surface contact

2021 ◽  
pp. 1-20
Author(s):  
Hua Zhou ◽  
Xinhua Long ◽  
Guang Meng ◽  
Xianbo Liu
Keyword(s):  
Contact Stiffness ◽  
Classical Model ◽  
Surface Profile ◽  
Bolted Joints ◽  
Normal Stiffness ◽  
Proposed Model ◽  
Stiffness Model ◽  
Fractal Roughness ◽  
Rough Surface Contact ◽  
Stiffness Loss

Abstract A revised fractal contact model considering asperity interactions is proposed. The displacement of mean of asperity heights is used to represent the effects of the asperity interactions. Then the critical contact area will be dependent on the contact load and the contact stiffness will be an integral whose integrand is an implicit expression. The fractal dimension and the fractal roughness are obtained by the measurement of surface profile to calculate the theoretical contact stiffness. The measurement of deformation is conducted to obtain the actual contact stiffness for verification, the results show that the proposed model is closer to the experimental results than other models without considering asperity interactions. Once the contact stiffness is determined, a new total normal stiffness model for bolted joints considering the contact of two rough surfaces is also proposed. Since the contact stiffness is dependent on the clamped force, the total normal stiffness for bolted joints is calculated iteratively at given initial preload and external separating force. Different from the classical model, the total normal stiffness for bolted joint decreases with the external separating force increases, and this stiffness loss will become larger with initial preload decreases. In this sense, the proposed total normal stiffness model is a way to determine the suitable initial preload for different sizes of bolts when the stiffness loss is restricted to a certain range.

An improved stiffness model for line contact elastohydrodynamic lubrication and its application in gear pairs

2020 ◽  
Vol 72 (5) ◽  
pp. 703-708 ◽  
Author(s):  
Jiaxing Pei ◽  
Xu Han ◽  
Yourui Tao
Keyword(s):  
External Load ◽  
Contact Stiffness ◽  
Elastohydrodynamic Lubrication ◽  
Line Contact ◽  
Content Type ◽  
Meshing Stiffness ◽  
Proposed Model ◽  
Stiffness Model ◽  
Film Stiffness ◽  
Ehl Contact

Purpose The purpose of this paper is to propose an simple and efficient stiffness model for line contact under elastohydrodynamic lubrication (EHL) and to investigate the gear meshing stiffness by the proposed model. Design/methodology/approach The method combines the surface contact stiffness and film stiffness as EHL contact stiffness. The EHL contact stiffness can be calculated by the external load and displacement of the load action point. The displacement is the sum of deformation of the film and contact surface and is equal to the distance of the mutual approach of two contact bodies. Findings The conclusion is drawn that the contact stiffness calculated by the proposed model is smaller than that by the minimum film model and larger than that by the mean film model. It is also concluded that the gear meshing stiffness under EHL is slightly smaller than that under dry contact. Originality/value The EHL contact stiffness can be obtained by the increment of external load and mutual approach directly. The calculation of oil film stiffness and surface contact stiffness separately is avoided. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-11-2019-0465

Rotordynamic Analysis of Rotor–Stator Rub Using Rough Surface Contact

2016 ◽  
Vol 138 (2) ◽  
Author(s):  
Philip Varney ◽  
Itzhak Green
Keyword(s):  
Rough Surface ◽  
Contact Force ◽  
Bulk Material ◽  
Contact Stiffness ◽  
Contact Model ◽  
Real Surface ◽  
Time Step ◽  
Surface Contact ◽  
Orbit Analysis ◽  
Rough Surface Contact

Undesirable rotor–stator rub is frequently observed in rotordynamic systems, and has been the subject of many investigations. Most of these studies employ a simple piecewise-smooth linear-elastic contact model (LECM), where the rotor switches between noncontacting and contacting operation once the clearance is exceeded (various complications have been incorporated, though the essential model premises endure). Though useful as a first step, the LECM relies on an arcane contact stiffness estimate, and therefore does not emulate the actual contacting surfaces. Consequentially, the LECM fails to elucidate how real surface parameters influence contact severity and surface durability. This work develops a novel model for rotor–stator rub which is commensurate with reality by treating the surfaces as a collection of stochastically distributed asperities. Specifically, the elastoplastic Jackson–Green (JG) rough surface contact model is used to calculate the quasistatic contact force as a function of rotor displacement, where bulk material deformation and surface cumulative damage are ignored. A simple exponential fit of the contact force is proposed to reduce computational burden associated with evaluating the JG rough surface contact model at each simulation time step. The rotor's response using the LECM and JG rough surface contact model is compared via shaft speed bifurcations and orbit analysis. Significant differences are observed between the models, though some similarities exist for responses with few contacts per rotor revolution.

A MODIFIED COMPLETE NORMAL CONTACT STIFFNESS MODEL OF A FRACTAL SURFACE CONSIDERING CONTACT FRICTION

Fractals ◽  
2020 ◽  
Vol 28 (05) ◽  
pp. 2050081
Author(s):  
CHUNLING WEI ◽  
HUA ZHU ◽  
SHIHUI LANG
Keyword(s):  
Contact Stiffness ◽  
Fractal Dimensions ◽  
Frictional Resistance ◽  
Contact Model ◽  
Contact Friction ◽  
Fractal Surface ◽  
Normal Contact ◽  
Stiffness Model ◽  
Fractal Roughness ◽  
Normal Contact Stiffness

This paper presents a modified complete normal contact stiffness model of a fractal surface considering contact friction. We use this model to study the influence of fractal dimensions and fractal roughness on normal contact stiffness. The fractal micro-contact model of an asperity and the complete length scale contact model of fractal surface (both contrasting classical mechanics) are revised. The influence of frictional resistance at micro-contact interfaces on normal contact stiffness is also considered. Predictions of the new model are found to be in greater agreement with the results of the experiments than the predictions of the original model. The study analyzes the influence of fractal dimensions and fractal roughness on the normal contact stiffness. With the increase of these two fractal parameters, their influences on the normal contact stiffness are opposite and are different under high pressure and low pressure.

A Contact Stiffness Model of Machined Plane Joint Based on Fractal Theory

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Shuyun Jiang ◽  
Yunjian Zheng ◽  
Hua Zhu
Keyword(s):  
Contact Stiffness ◽  
Fractal Theory ◽  
Fractal Model ◽  
Experimental Results ◽  
Size Dependent ◽  
Contact Loads ◽  
Proposed Model ◽  
Stiffness Model ◽  
Surface Profiles ◽  
Plane Joint

A general contact stiffness model is proposed in this paper to study the contacts between rough surfaces of machined plane joints. The proposed model uses fractal geometry for surface topography description, elastic-plastic deformation of contacting asperities, and size-dependent contact stiffness of microcontacts, where the contact stiffness is derived from Hertz contact theory. Three cast iron specimens are produced from different machining methods (milling, grinding, and scraping), and their rough surface profiles are extracted. The structure function method was used to calculate each profile’s fractal dimension and scale coefficient. Both theoretical analysis and experimental results of contact stiffness are obtained for these specimens under different contact loads. The comparison between the theoretical contact stiffness and the experimental results at the interface indicates that the present fractal model for the contact stiffness is appropriate and the theoretical contact stiffness is consistent with the experimental data.

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