Contribution of dislocation pileups to acoustic nonlinearity parameter

This paper develops an analytical model to calculate the acoustic nonlinearity parameter induced by dislocation pileups in isotropic elastic solids. It shows that the pileup-induced acoustic nonlinearity parameter depends on the pileup length, number of dislocations in a pileup, Burgers vector, and dislocation density. Additionally, it is found that the formula for pileup-induced acoustic nonlinearity parameter has a similar mathematical form to those for other types of defects such as dislocation strings, dislocation dipoles, and extended dislocations. They are all scaled with a dimensionless parameter (L c h / b) n, where L c h is a characteristic length of the defect, b is the magnitude of the Burgers vector, and n is either 3 or 4.