Stress-dependent ultrasonic scattering in polycrystalline materials

Stress-dependent ultrasonic scattering in polycrystalline materials.

Stress-dependent elastic moduli of polycrystalline materials are used in a statistically based model for the scattering of ultrasonic waves from randomly oriented grains that are members of a stressed polycrystal. The stress is assumed to be homogeneous and can be either residual or generated from external loads. The stress-dependent elastic properties are incorporated into the definition of th...

Ultrasonic attenuation and backscattering in polycrystalline materials with nonspherical grains

An ultrasonic wave propagating through a microscopically inhomogeneous medium, such as polycrystalline materials, is subject to scattering at the grain boundaries as well as other inhomogenities. The fraction of energy removed from the incident wave is responsible for important phenomenon like attenuation, dispersion, and background “noise" associated with a given ultrasonic inspection system. ...

Mapping of Materials Stress with Ultrasonic Tomography

It is _known _that internal stress concentrations can give rise to microcracks which then grow when the str~cture 1s subJected to external forces. It has also been found that the velocity'of sound is altered as ~t propagates through a region of stress. In this paper we discuss a technique called ComputerAsslsted Tomography (~AT) and describe ~n application that provides pictures of stress field...

Ultrasonic Attenuation in Polycrystalline 5n Aluminium

Elastic wave propagation and scattering in heterogeneous, anisotropic media: Textured polycrystalline materials

Elastic wave propagation and scattering in heterogeneous, anisotropic media: Textured polycrystalline materials" (1999). Faculty Publications from Nebraska Center for Materials and Nanoscience. Paper 60. The propagation of elastic waves through heterogeneous, anisotropic media is considered. Appropriate ensemble averaging of the elastic wave equation leads to the Dyson equation which governs th...