Practical approaches to single sided nonlinear measurements

The mechanism by which a travelling wave propagates through a nonlinear medium is of interest due to the large body of research on its potential to assess the damage state of structures. Typically measurements are made of changing nonlinearity on a single specimen geometry. The research in this paper considers the effect of damping on the nonlinear harmonic generation of a wave travelling through a medium in the presence of bulk material nonlinearity and the necessary scalings for real non-continuous measurements. A new formulation of the generation of nonlinearity is demonstrated. A numerical solution is also developed and both approaches are used to highlight potential issues with nonlinear measurement techniques. In addition to this behaviour parameters are developed that take into account the type of input wave and windowing employed on reception. This highlights a difficulty in comparing practical measurements where conditions identical to those in the analytical formulation cannot be used. In additi...