Residual Stress Determination Using Acoustoelasticity

Abstract

A technique for the complete nondestructive evaluation of plane states of residual stress is presented. This technique is based on the acoustoelastic effect in which the presence of the residual stress causes a shift in the speed at which a wave propagates through the material. The particular acoustoelastic technique considered here employs longitudinal waves propagating normal to the plane of the stress. Such waves experience a shift in propagation speed which, for an isotropic material, is proportional to the sum of the principal stresses. A Poisson’s equation for the in-plane shear stress is obtained from the two-dimensional equilibrium equations in which the forcing function is obtained directly from the measured velocity variations. Once this equation is integrated for the shear stress, the normal stresses may be evaluated directly from the equilibrium equations. In this paper, the basic equations are derived for the case of an anisotropic material. The experimental and numerical procedures are reviewed, and results of residual stresses in an aluminum ring are presented.

Recent progress in residual stress measurement techniques

“…They can be divided into two categories depending on whether damage will be caused to the specimen or not: Mechanical release methods [10] such as the hole-drilling, sectioning, ring core, crack compliance and layer removal; and physical determination [11][12][13][14][15] such as X-ray diffraction, magnetics, ultrasonics and Raman methods.…”

An Ultrasonic Study on Anelasticity in Metals

“…A major focus of these studies is on the higher order elastic constants and their relation to the microstructure of the material. Ultrasonic techniques have also proven quite useful for characterizing the stress state of a material [4][5][6]. Recently, while using the magnetoacoustic (MAC) method to investigate the residual stress in various steel samples, a time dependent change in the results was observed.…”

Elastic Constants of a Stressed Layer from Surface Acoustic Wave Measurements

“…Since this difference in velocity vanishes in an unstressed material, the phenomenon provides a direct indication of the presence of stress, and similar effects have been employed in various guises to map out stress distributions in materials [e.g. [1][2][3]. Although there are likely to be effects similar to shear wave birefringence for SAWs with predominantly shear horizontal polarisation, in most cases the effect of stress on velocity is not as clear cut, and the inverse problem is susceptible to errors in the elastic constants.…”