Abstract

Surface and Interface Characterization by Nonlinear Vibrations

S.I.Rokhlin, L.Wang (Ohio State University, Nondestructive Evaluation Program, Edison Joining Technology Center, Columbus, OH, USA)

e-mail: rokhlin.2@osu.edu

In tapping mode atomic force microscopy (AFM) the vibration response of a cantilever with nanotip is used to map a sample surface topography on the nanoscale. Nonlinear surface interaction forces control the frequency response of the cantilever. Numerical and analytical models are presented to analyze the effect of the surface interaction forces on this behavior using time dependent boundary conditions. It is shown that adhesion and viscoelastic forces are dominant in distinct regions of the nonlinear resonance characteristic of the cantilever and that the vibration amplitude and phase can be used for nanoscale property measurements. Good agreement is observed between the theoretical predictions and experiment. Similarly, time dependent boundary conditions are formulated for a high frequency ultrasonic wave propagating through an imperfect interface between two solids undergoing low frequency vibration. The interfacial conditions are modeled using micromechanics of randomly rough contacting surfaces. It is shown that under these conditions parametric mixing occurs for the high frequency reflected wave. The predictions of the model are compared with experiment.

Section : 3