Abstract
In the present paper, the acoustical effects caused by elasto-plastic finite deformations in slightly orthotropic materials are theoretically investigated using the theories of finite deformations and plasticity in which the plastic strain increments are expressed with stress deviations and their increments. From analytical results, it is found that the expressions for the elastic-plastic strain-velocity relations of acoustic waves propagating in slightly orthotropic materials can be derived skillfully with aid of Jaumann co-rotational rate and can be reduced to the theoretical results derived by Iwashimizu and Kubomura in the elastic state. Further in order to remove the previous discrepancies between the theoretical results and the experimental ones about the influence of plastic deformations upon the acoustoelastic effects, the author discusses the influence of the deviation of stress increments on the plastic strain increments.
