1. Nabel, E. and Mundry, E., “Evaluation of Echoes in Ultrasonic Testing by Deconvolution,” Mat. Eval., 59–61, 77, Jan., 1978. “This paper is based on what has turned out to be a good tool for ultrasonic echo analysis, namely, linear system theory, and will report some effects of fundamental importance for ultrasonic spectroscopy and deconvolution. In many cases the importance of these effects is not recognized, although they are responsible for most of the differences between experimental results and theory. The paper deals with the improvements in the analysis of echo indications by the calculation of the impulse response of a reflector (deconvolution of ultrasonic echoes). The importance of phase information is emphasized, and the influence of the low frequencies (i.e., the low diffraction orders) on the experimental results is shown. As an example, the result of a simulated convolution will be demonstrated with respect to the theory of replica pulses published by Freedman.” (Author) 11 refs.
2. NDT International;C Tamburelli,1977
3. Budiansky, B. and Rice, J. R., “On the Estimation of a Crack Fracture Parameter by Long-Wavelength Scattering,” J. App. Mech. 45 (2). “Attention is focussed herein on the possibility of estimating the fracture-mechanics parameter kI = (KI)max/σ associated with a flat crack of initially unknown dimensions and orientation by using long-wavelength NDE measurements. Here KI is the mode I stress-intensity factor associated with tension σ normal to the plane of the crack, and “max” denotes the largest value along the crack perimeter. The estimates will be made on the basis of the long wavelength studies by Gubernatis, et al. [1]3, and certain properties of elliptic cracks that are nearly shape invariant.” (Author) 2 refs.
4. Canella, G., “The Ultrasonic Field in Water and Steel,” NDT (London), 38–42 (Feb., 1975). “The investigations of the ultrasonic field of transducers used in ndt, had two objects. The first was to compare directly propagation in steel and water. The second was to study the contribution of the beam spread to the attenuation of the echo. The beam spread is considered as a function of the area of the reflector and its distance from the transducer.” (Author) 9 refs.
5. NDT International;JC Baboux,1977