Showing papers by "Ajit Mal published in 2016"
TL;DR: In this paper, a specific structure is analyzed with different levels of complexities in an effort to determine the propagation characteristics of the waves in order to determine their propagation characteristics for effective damage identification.
Abstract: The integrity of safety-critical structural composites can be enhanced by the use of innovative ultrasonic nondestructive evaluation techniques. Among the various existing techniques, guided wave methods provide a good promise in terms of sensitivity to a variety of damage types or defects and the extent of the area that can be monitored, given the ability of these waves to travel relatively long distances within the structure under investigation. In comparison with isotropic metallic structures, wave propagation in composite structures presents additional complexity for effective damage identification. The material inhomogeneity, anisotropy, and the multilayered construction of composite materials lead to significant dependence of wave modes on laminate layup configurations, direction of propagation, frequency, and interface conditions. In this article, a specific structure will be analyzed with different levels of complexities in an effort to determine the propagation characteristics of the waves. The i...
41 citations
TL;DR: In this article, the free-end Lamb wave reflection at a free end as well as the interaction of Lamb waves with upward and downward step discontinuities is solved using an analytical approach.
41 citations
21 Mar 2016
TL;DR: In this article, the authors developed a semi-analytical technique for estimating the energy loss in a resonator mounted on a plate substrate. But this approach is distinguished from prior semianalytical approaches by the absence of an applied load.
Abstract: This paper develops a new semi-analytical technique for estimating the energy loss in a resonator mounted on a plate substrate. Resonator energy loss due to interaction with its substrate (so called “anchor loss”) has been widely studied, but most treatments have assumed a semi-infinite medium due to the small dimensions of the resonator compared to the substrate thickness. Recent high quality factor resonators, though, typically have resonant frequencies from a few kilohertz up to several hundred kilohertz and in these cases, due to the wavelengths involved, the substrate is more accurately treated as a plate. A procedure is developed whereby modal analysis is performed on a finite element model that is coupled to analytical expressions for the plate Lamb waves. This approach is distinguished from prior semi-analytical approaches by the absence of an applied load. Thus, a more fundamental treatment of dynamics of the coupled system is possible.
1 citations