Abstract

Development of a Nonlinear Boundary Condition Approach as a New Model for the Nonlinear Acoustic Interface Problem

B.O'Neill, J.Sadler, R.Maev (Department of Physics, University of Windsor, Windsor, Canada)

e-mail: oneillb@uwindsor.ca

A new theoretical approach to dealing with acoustic interface nonlinearities is presented. This approach allows one to write down a set of nonlinear boundary conditions for the interface, which then allows solutions to be developed within the conventional framework of continuum mechanics. The boundary condition approach provides a number of significant advantages over other competing approaches. The first is that it provides a technique which can deal with both bilateral (continuous) and unilateral (clapping, sliding) nonlinear interfaces in a unified way. Second, it may be developed to deal effectively with oblique incidence and anisotropy. Third, it allows one to deal with multilayer systems in an intuitive way within the regular framework of continuum mechanics. Results for each of these general cases are demonstrated by finding solution using a time domain perturbation expansion. Particular attention is paid to the theoretical duplication of observable anomalous nonlinear effects at defect type interfaces.

Section : 1