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Dry Static Friction in Metals: Experiments and Micro-Asperity Based Modeling

Sista, Sri Narasimha Bhargava
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1416579128

Abstract Details

2014, PhD, University of Cincinnati, Engineering and Applied Science: Mechanical Engineering.
Friction and wear are two complex phenomena that occur at interfaces of contacting surfaces. The genesis of these phenomena is mapped down to adhesive forces and mechanical deformation of micro-asperities. The classical laws of friction hold for rigid bodies and deformable bodies undergoing small deformations but are not valid for materials that undergo large and time-dependent deformations. Usually, the large deformation of these materials at the micro-scale and the topography produced by different manufacturing processes introduce complex frictional behavior between the surfaces. This has led to investigations of the deformation of micro-asperities to capture friction and wear at micro-scale in order to predict the macroscale interfacial behavior. The overall objective of this study is to develop a micro-asperity-based model of friction in engineering surfaces. In this study, we present the development of a micro-asperity based model for friction between isotropic, Gaussian, elastoplastic surfaces. In order to do this, we present a statistical model that is Gaussian and isotropic in nature, to represent the surface micro-topography. We present a novel methodology for estimating scale-independent properties of the surface model from the measured surface profile. The normal and shear forces supported by a single asperity are then calculated using the micro-asperity model and the overall contact forces at macroscopic scale are calculated by using statistical homogenization. In this study, we assume the material behavior to be linearly elastic-perfectly plastic to model the frictional behavior between metallic surfaces. In particular, we develop the constitutive models of both friction force and coefficient of friction for Aluminum 6061 alloy surfaces with Gaussian, isotropic surface topography. We also study the effect of various entities such as surface roughness, material properties, normal load and adhesive forces on the overall friction behavior. We also perform an experimental investigation of friction between Aluminum 6061 surfaces in order to collect a comprehensive data set that suitable in calibrating and validating micro-asperity models. The calibration of surface material and topographical properties are carried out within Bayesian framework. The quantitative comparison of model predictions against experiments shows that while the micro-asperity models are successful in qualitatively predicting the experimental behavior, they fail to do so quantitatively. Based on the results obtained in this study and other literature, we also suggest a potential way forward in making these models more robust and reliable.
Kumar Vemaganti, Ph.D. (Committee Chair)
Kelly Anderson, Ph.D. (Committee Member)
Amit K. Kaushik, Ph.D. (Committee Member)
Jim Shepherd, Ph.D. (Committee Member)
Yijun Liu, Ph.D. (Committee Member)
Vijay Vasudevan, Ph.D. (Committee Member)
149 p.
Mechanical Engineering
static friction; surface roughness; micro-asperity; Bayesian statistics; statistical homogenization; uncertainty quantification

Recommended Citations

Citations

  • Sista, S. N. B. (2014). Dry Static Friction in Metals: Experiments and Micro-Asperity Based Modeling [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1416579128

    APA Style (7th edition)

  • Sista, Sri Narasimha Bhargava. Dry Static Friction in Metals: Experiments and Micro-Asperity Based Modeling. 2014. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1416579128.

    MLA Style (8th edition)

  • Sista, Sri Narasimha Bhargava. "Dry Static Friction in Metals: Experiments and Micro-Asperity Based Modeling." Doctoral dissertation, University of Cincinnati, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1416579128

    Chicago Manual of Style (17th edition)

ucin1416579128
470
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This open access ETD is published by University of Cincinnati and OhioLINK.