Viscoelastic Effects in Nanometer-Scale Contacts Under Shear

Abstract

We demonstrate the effects of shear modulation on the viscoelastic response of nanometer-scale single-asperity contacts under static and dynamic loading conditions. Contact stiffness and relaxation time are determined for contacts to poly(vinylethylene) using a scanning force microscope (SFM). Knowledge of the torsional stiffness kQ of the SFM cantilever is not required to determine the relaxation time. The relaxation time was several orders of magnitude slower than the bulk relaxation time but decreased slowly to the bulk value as the sample age increased. Contacts showed no evidence of microslip. We show that the shear response observed during the making and breaking of the contacts provides information about the time evolution of the contact area that is not available in force vs. distance curve measurements.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1998
Accession Number
ADA465036

Entities

People

  • K. J. Wahl
  • S. V. Stepnowski
  • W. N. Unertl

Organizations

  • United States Naval Research Laboratory

Tags

DTIC Thesaurus Topics

  • Amplitude
  • Differential Equations
  • Displacement
  • Elastic Materials
  • Electron Microscopes
  • Frequency
  • Materials
  • Mechanical Properties
  • Mechanics
  • Microelectromechanical Systems
  • Microscopes
  • Military Research
  • Modulus Of Elasticity
  • Relaxation Time
  • Scanning Electron Microscopes
  • Shear Modulus
  • Stiffness

Readers

  • Mechanical Engineering/Mechanics of Materials.
  • Nanoscale Plasmonic Nanotechnology