Crack detection by resonant frequency measurements
- 131 Downloads
The resonant frequency of 304 stainless steel specimens with a center-drilled hole has been measured as a function of fatigue cycles during crack initiation and propagation. Simultaneous measurements of crack lengths by scanning electron microscopy yield the resonant frequencyvs crack length. The change of resonant frequency is equivalent to the change of an effective elastic modulus. Analytical results for a “spring” model to predict the change in effective modulus due to the presence of cracks have been compared with results derived from resonant tests. In the model, the load transfer across the plane of the crack is represented by a distribution of springs of stiffness that depends on the crack length. Good agreement is observed between theory and experiment for cracks up to 500-μm long. The model may be used to obtain the crack length from resonance measurements.
KeywordsFatigue Elastic Modulus Material Transaction Resonant Frequency Crack Length
Unable to display preview. Download preview PDF.
- 1.R.B. Mignogna, J.C. Duke, Jr., and R.E. Green, Jr.:Mater. Eval., 1980, Mar., pp. 37–42.Google Scholar
- 2.J.D. Achenbach, M.E. Fine, I. Komsky, and S. McGuire: inCyclic Deformation, Fracture, and Nondestructive Evaluation of Advanced Materials, MR. Mitchell and O. Buck, eds., ASTM STP 1157, ASTM, Philadelphia, PA, 1992, pp. 241–50.Google Scholar
- 3.S.M. McGuire, M.E. Fine, O. Buck, and J.D. Achenbach:J. Mater. Res., 1993, vol. 8, pp. 2216–23.Google Scholar
- 4.M.E. Fine:Symposium on Determination of Elastic Constants, ASTM STP 129, ASTM, Philadelphia, PA, 1952, pp. 43–67.Google Scholar
- 9.W. Kurz and B. Lux:High Temp. High Pressure, 1969, vol. 1, pp. 387–99.Google Scholar
- 11.H. Tada, P. Paris, and G. Irwin:The Stress Analysis of Cracks Handbook, Del Research Corp., St. Louis, MO, 1973, p. 19.9.Google Scholar