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Keynote Speakers
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Santosh Kapuria,
A Senior Research Leader
Professor, Department of Applied Mechanics, Indian Institute of Technology Delhi,
New Delhi 110016,
email: kapuria@am.iitd.ac.in
Dr. Santosh Kapuria is currently R. Gupta Chair Professor of Applied Mechanics at Indian Institute of Technology
Delhi in New Delhi, India. He received his PhD in Applied Mechanics from Indian Institute Technology Delhi, M.E.
from Indian Institute of Science, Bangalore in Structural Engg in 1991, and B.E. from Jadavpur University, Calcutta
in 1989. He did his postdoctoral research in Technische Universität Darmstadt, Germany and Stanford University, USA.
Prior to joining IIT Delhi, he worked in Engineers India Limited (EIL), a premier consultancy organization of Asia
and gained a rich and distinguished industrial experience of eleven years in advanced engineering.
Prof. Kapuria is a leading researcher in the cutting edge area of smart (multifunctional) structures. Specifically,
his work pertains to laminated structures made of advanced composites, sandwich, or functionally graded materials
(FGMs) that are integrated with distributed piezoelectric actuators and sensors. Such materials are used to achieve
control of unwanted vibrations, shape control, and damage detection in inaccessible structures. Prof. Kapuria has
made seminal contributions by developing new models for accurate analysis of these structures, experimentally
validating some of these models, developing new finite elements for their numerical implementation and alsoapplying
them for studying active vibration control as well as structural health monitoring. He has published over 100 papers
in top quality international journals, which are highly cited.
His high-quality research has earned him national and international recognitions. He received the prestigious the
Humboldt Research Fellowship in 2005, and the Fulbright Senior Research Fellowship in 2009. He is a Fellow of the
Indian National Academy of Engineering. He served as the Co-Chair of the second Asian Conference on Mechanics of
Functional Materials and Structures (ACMFMS) held in China in 2010, and the General Chair of the third ACMFMS held
in India in December, 2012. He is an Editorial Board Member of Journal of Thermal Stresses, and is currently a Guest
Editor of ACTA MECHANICA journal for a special issue on mechanics of functional materials and structures.
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Active Vibration Control of Smart Piezolaminated Composite Structures using Nonlinearity in Strong Field Actuation
Increasing demand for the development of lightweight structures particularly in aerospace,
automobile and space applications has brought active vibration control of structures into the focus
of research in recent times. Piezoelectric materials are widely used as sensors and actuators for
such applications. But, the studies on active vibration control of plate and shell type structures
reported so far have considered only a linear behaviour of the piezoelectric materials. Experiments
have, however, shown that piezoceramic materials exhibit constitutive nonlinearity, when the
applied electric field exceeds the coercive limit. In this talk, we will discuss a theoretical
framework for modeling active vibration control of smart multilayered plates and shallow shells
integrated with piezoceramic sensors and actuators, considering their constitutive nonlinearity
under strong electric field. An efficient layerwise theory, which is nearly as accurate as a three
dimensional (3D) solution, but is as economical as an equivalent single-layer theory with only five
displacement unknowns is employed for the laminate mechanics. For the linear transient analysis of
a piezo-sandwich plate, the computational time for the finite element (FE) model based on this
theory has been found to be nearly 1/300th of that required for 3D FE analysis using ABAQUS,
yielding nearly the same accuracy. The nonlinearity is modeled using rotationally invariant second
order nonlinear constitutive equations, with the assumption of large electric field and small
strains. The nonlinear finite element model for dynamic response is developed consistently using
the extended Hamilton’s principle. The nonlinear system is transformed to an equivalent linear
system using the feedback linearization approach, through control input transformation. The linear
quadratic Gaussian (LQG) controller is adopted for control of the equivalent system. The results
predicted by the nonlinear model compare very well with the experimental data available in the
literature for static response. The effect of the piezoelectric nonlinearity on the static response
and active vibration control is studied for piezoelectric bimorph as well as hybrid laminated
plates and shells with isotropic, composite and sandwich substrates. It is revealed that, using the
piezoelectric nonlinearity, the vibration control can be achieved at a much lower actuation
potential than predicted by the linear model. While in the linear model, control voltage is almost
independent of the actuator thickness, its nonlinear prediction reduces significantly with the
decrease in the actuator thickness.
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