Spectral Finite Element Method Wave Propagation, Diagnostics and Control in Anisotropic and Inhomogeneous Structures

Wave propagation is an exciting ?eld having applications cutting across many disciplines. In the ?eld of structural engineering and smart structures, wave propagation based tools have found increasing applications especially in the areaofstructuralhealthmonitoringandactivecontrolofvibrationsandnoise. Inaddition,therehasbeentremendousprogressintheareaofmaterialscience, wherein a new class of structural materials is designed to meet the parti- lar application. In most cases, these materials are not isotropic as in metallic structures. They are either anisotropic (as in the case of laminated composite structures) or inhomogeneous (as in the case of functionally graded mate- als). Analysis of these structures is many orders more complex than that of isotropic structures. For many scientists/engineers, a clear di?erence between structural dynamics and wave propagation is not evident. Traditionally, a structural designer will not be interested in the behavior of structures beyond certain frequencies, which are essentially at the lower end of the frequency scale. For such situations, available general purpose ?nite element code will satisfy the designer’s requirement. However, currently, structures are required tobedesignedtosustainverycomplexandharshloadingenvironments. These loadings are essentially multi-modal phenomena and their analysis falls under the domain of wave propagation rather than structural dynamics. Evaluation of the structural integrity of anisotropic and inhomogeneous structures s- jected to such loadings is a complex process. The currently available analysis tools are highly inadequate to handle the modeling of these structures. In this book, we present a technique called the “Spectral Finite Element Method”, whichwebelievewilladdresssomeoftheshortcomingsoftheexistinganalysis tools.

Introduction Introduction to theory of anisotropic and inhomogenous materials Idealization of wave propagation and solution techniques Wave propagation in one-dimensional anisotropic structures Wave propagation in one-dimensional inhomogenous structures Wave propagation in two-dimensional anisotropic structures Wave propagation in two-dimensional inhomogenous structures Solution of inverse problems: source and system identification Application of SFEM to SHM: simplified damage models Application of SFEM to SHM: efficient damage detection techniques Spectral finite element mehod for active wave control

Prof. S. Gopalakrishnan is an Associate Professor at the Indian Institute of Science, Bangalore, India. He has a decade of experience in applying wave based techniques for solving various structural engineering related problems. He is internationally recognized as one of the experts in the field, and is one of the few people responsible for popularizing the use of SFEM through his research publications and presentations.

Dr A. Chakraborty is a Senior Researcher at General Motors India.

Dr Roy Mahapatra is an Assistant Professor at the Indian Institute of Science, Bangalore, India. His research activities are related to the mechanics and dynamics of solid-state engineering materials and structures, and the study of complex systems.