resonances are intrinsic characteristics of an elastic object, which are completely independent of thesource of excitation. the appropriate utilization of the information contained within the resonancespectra and the identification of the resonance frequencies of the object can be used as a potent toolfor material characterization. in this paper, a new mathematical model for the wave diffractio...

The partial differential equation for the wave function in the problem of the diffraction of light by an ultrasonic wave is derived as the result of transformations and related approximations of the electrical field equation itself. It is shown that this way of treating the diffraction problem is equivalent to the generating function method applied to the Raman-Nath system of difference-differe...

The use of PSpice models for piezoelectric devices and ultrasonic transmission media is of major importance when designing electronics for ultrasonic systems. Today, these models include viscoelastic loss but disregard loss due to diffraction, i.e. beam spreading. This paper presents a method for the inclusion of diffraction loss in PSpice simulations of ultrasonic systems. The conductive loss ...

phenolic resins have been widely used for selective high technology applications due to their excellent ablative properties, structural integrity and thermal stability that make them appropriate for thermal insulation materials, wood products industry, coatings, moulding compounds and composite materials. polymer layered silicate nanocomposites based on montmorillonite (mmt) have attracted a gr...

TOFD technique is based on diffraction of ultrasonic waves on the tips of discontinuities instead of reflection on the interface of discontinuities. When ultrasound is incident at linear discontinuities such as crack diffraction takes place at its extremities in addition to the usual reflected wave. The diffracted energy is emitted over a wide angular range, presumed to originate at the extremi...

Characterizing the wave field produced by an ultrasonic transducer is one important part of developing a complete measurement model of an ultrasonic NDE system. Within the paraxial approximation [1], this wave field can be expressed as a quasi plane wave field modified by a diffraction correction tenn to account for the 3-D effects of having a finite beam generated by the transducer. Previously...

High contrast and resolution in phased array ultrasonic images are of importance for accurate evaluation. The spread of the ultrasonic beam is one cause of the images being unsharp. One technique for reducing the influence of the beam spread, and thereby improving the image quality, is by deconvolving the data with the point spread function of the ultrasonic beam. By assuming that the material ...