A surface acoustic wave technique for monitoring the growth behavior of small surface fatigue cracks

The theory of Kino and Auld which relates the reflection coefficient of acoustic waves from a crack to its size is summarized. A scattering model is evaluated from this theory concerning the reflection of surface acoustic waves (SAW) from a small surface fatigue crack at a frequency such that the crack depth is much smaller than the acoustic wavelength. Acoustic predictions of crack depth are compared to postfracture measurements of depth for small surface cracks in Pyrex glass, 7075-T651 aluminum, and 4340 steel. Additionally, the minimum detectable crack depth as limited by the acoustic noise level is determined for several typical aluminum and steel alloys. The utility of SAW reflection coefficient measurements for inferring crack depth, crack growth, and crack opening behaviorin situ during fatigue cycling is discussed.

[1]  O. Buck,et al.  Higher harmonics of finite amplitude ultrasonic waves in solids , 1976 .

[2]  B. Khuri-Yakub,et al.  The design of efficient broadband wedge transducers , 1978 .

[3]  Drew V. Nelson,et al.  Long Wavelength Rayleigh Wave Scattering from Microscopic Surface Fatigue Cracks , 1982 .

[4]  W. Morris,et al.  Growth rate models for short surface cracks in AI 2219-T851 , 1981 .

[5]  G. Kino.  The application of reciprocity theory to scattering of acoustic waves by flaws , 1978 .

[6]  I. A. Viktorov.  Rayleigh and Lamb Waves , 1967 .

[7]  William M. Visscher.  Scattering of Rayleigh Surface Waves from Partly-Closed Surface-Breaking Cracks , 1984 .

[8]  R. E. Beissner,et al.  Correlations Between Advanced Nondestructive Evaluation Methods and Fracture Mechanics Parameters , 1980 .

[9]  J Lankford,et al.  Fatigue Mechanisms: Advances in Quantitative Measurement of Physical Damage , 1983 .

[10]  M. T. Resch,et al.  The Use of Surface Acoustic Waves to Study Small Fatigue Cracks in 7075-T651 Aluminum and 4340 Steel , 1985 .

[11]  D. Thompson,et al.  Review of Progress in Quantitative Nondestructive Evaluation , 1982 .

[12]  T. A. Gray,et al.  A Model for the Ultrasonic Scattering from Multi-Branched Cracks , 1985 .

[13]  Bulk and Surface Wave Scattering from Surface Breaking Cracks , 1982 .

[14]  James K. Knowles,et al.  On a class of conservation laws in linearized and finite elastostatics , 1972 .

[15]  L. Schmerr.  The Scattering of Elastic Waves by Isolated Cracks Using a New Integral Equation Model , 1982 .

[16]  R. B. Thompson,et al.  Interactions of Simulated Partially Closed Cracks with Acoustic Waves , 1984 .

[17]  W. Morris.  The noncontinuum crack tip deformation behavior of surface microcracks , 1980 .

[18]  Rayleigh Spectroscopy For Characterizing Surface Cracks , 1982 .

[19]  B. Auld,et al.  Acoustic fields and waves in solids , 1973 .

[20]  R. B. Thompson,et al.  THE EFFECTS OF CRACK CLOSURE ON ULTRASONIC SCATTERING MEASUREMENTS , 1984 .

[21]  J. Newman,et al.  Analysis of surface cracks in finite plates under tension or bending loads , 1979 .

[22]  J. Achenbach,et al.  Scattering Of Obliquely Incident Rayleigh Waves by a Surface-Breaking Crack , 1984 .

[23]  A. H. Harker,et al.  Numerical modelling of the scattering of elastic waves in plates , 1984 .

[24]  B. Auld.  General electromechanical reciprocity relations applied to the calculation of elastic wave scattering coefficients , 1979 .

[25]  Albert S. Kobayashi,et al.  Stress Intensity Factors for Semicircular Cracks: Part 2—Semi-Infinite Solid , 1967 .

[26]  Jan Drewes Achenbach,et al.  An inversion integral for crack-scattering data , 1979 .

[27]  Saw NDE Techniques for Monitoring the Growth Behavior of Small Surface Fatigue Cracks , 1984 .