Deducing energy dissipation from rheological response

We propose a method for analyzing the nonlinear response regime of confined liquids driven harmonically in measurements using surface force apparatus. The approach is based on calculating the average energy dissipation in the system, and it provides a way to deduce the microscopic parameters which a re responsible for the dissipation. We compare the method with the widely u sed linear fourier analysis in the case of the Tomlinson model and discuss the meaning and applicability of the two approaches. (C) 1999 American Inst itute of Physics. [S0021-9606(99)51102-1].