Piezoelectric materials have secured a significant place in
the field of structural health monitoring (SHM) and vibration energy harvesting
over the past two decades. Although these materials are available in several
forms and configurations, the efficacy of curved configurations is still
unexplored. This study investigates, both experimentally and numerically, the
potency of the curved configuration of the piezo transducers over the straight
configuration when embedded in reinforced concrete (RC) structures for
vibration energy harvesting and SHM. This book, based on the M.Tech thesis of
the lead author completed in the Department of Civil Engineering at IIT Delhi,
covers the comparative analysis of (a) open-circuit voltage generated across
the piezo transducers; (b) the power developed under the impedance matching
conditions; and (c) the potential of power storage into capacitors for both
configurations. The book also experimentally examines the hitherto unexplored
damage detection capability of the curved piezo transducers by the
electro-mechanical impedance (EMI) technique. Results clearly demonstrate that
curved piezo transducers exhibit better performance in comparison to straight
configurations for both SHM and vibration energy harvesting. A finite element
(FE) analysis is also performed through a 3-D model of the real-life-sized RC
beam with straight and curved piezo transducers embedded inside to evaluate the
effect of various parameters such as the angle of bend, the thickness, the
number of elements and the position of placement of the transducers for
vibration energy harvesting. The FE simulations reveal an optimum range of the
angle of bend as 130 to 160 degrees. There is a substantial impact of the
increase in thickness of the transducers for vibration energy harvesting in
terms of the open-circuit voltage. The numerical analysis also suggests that
the optimum position of placement of the piezo transducers is towards the top
or bottom of the beam cross-section. As a preliminary step towards the analytical
analysis of curved piezo transducers for vibration energy harvesting, a 2-D
skeletal analytical model of an RC beam embedded with a curved piezo transducer
is developed by formulating a MATLAB code based on the direct stiffness
approach. The effect of the curvature and the thickness of the transducer is
also analysed and compared with the findings of the numerical investigations.
Also, contrary to the numerical investigation results, the thickness of the
curved transducer is found to hardly have any effect on the terminal voltage
generated across it. This is because the 3-D effects of the structure and the
strain variation across the thickness of the transducer are not considered in
the analytical model where each element is considered as a 1-D element. Hence,
it is recommended to extend the research to 3-D analytical models. The outcomes
of the experimental and numerical investigations are very pivotal for the
implementation of curved piezo transducers on real-life RC structures for
improved vibration energy harvesting and structural health monitoring. This
includes assessment of damages, either gradual during the lifespan of the
structure or after some major event such as earthquakes. The sensor, being
embedded inside the structure, is well protected from environmental degradation
and can enable dynamic strain-based monitoring of the structure during normal
operation or during an extreme event such as an earthquake which is technically
simpler as compared to the traditional displacement-based monitoring and has
special significance for monitoring of bridges under vehicular loads and for
checking compliance to the Indian Roads Congress (IRC codes). Post-earthquake
or during periodical SHM checks, the condition of the structure can be
evaluated using the same sensor by employing the EMI technique.
Author (s) Details
Aleena V Krishnanunni
Assistant Engineer, Thottiyar Hydro-Electric Project, Kerala State
Electricity Board Ltd., Kerala, 685606, India.
Naveet Kaur
Senior Scientist, CSIR-Central Road Research Institute, Mathura Road,
Delhi-110025, India.
Suresh Bhalla
Professor, Civil Engineering Department, Indian Institute of Technology
Delhi, Hauz Khas, Delhi 110016, India.
Please see the book here:- https://doi.org/10.9734/bpi/mono/978-93-48006-36-3
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