Cantilever Dynamics With Attractive and Repulsive Tip Interactions

Abstract

In tapping mode atomic force microscopy (AFM) operations, typically, a micro-scale cantilever undergoes long-range attractive and short-range repulsive forces as it approaches the surface. Due to the strong nonlinearity of the tip-sample interaction forces, a variety of nonlinear phenomena has been observed. In order to obtain a better understanding of such phenomena, in this work, a macro-scale experimental system is constructed with attractive and repulsive tip interactions. Magnetic forces are used to generate the attractive forces, and impact with a compliant surface is used to produce the repulsive forces. A reduced-order model for this system has been developed with Derjaguin-Muller-Toporov (DMT) contact mechanics. In prior work conducted in the group, period-doubling bifurcations have been observed close to near grazing conditions when AFM cantilevers are operated between first and second natural frequencies of the system. This phenomenon is further explored in this article.