Environmental Engineering Reference
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(Tadigadapa and Mateti
2009
; Yu et al.
2008
; Zhao et al.
2007
), among others
(Boller
2000
). Despite these advancements, these SHM systems possess certain
limitations that sometimes make it challenging for them to diagnose a structure's
health. While limitations vary between sensor platforms, in most cases, sensors are
discrete transducers that only measure data at instrumented locations. Spatial
structural response is usually obtained using a dense network of sensors and
interpolation. Most sensors only measure structural response, and physics-based
models or statistical methods are needed for inferring information about damage.
Unlike the aforementioned manmade sensing technologies, nature and its
diverse creations have perfected biological assemblies and functionalities to enable
the five senses of touch, visual, auditory, olfactory, and taste. In fact, humans have
historically relied on biological inspirations to create artificial systems that
mimicked the functionalities of many creatures. For example, camouflage tactics
used in the military (i.e., planes, ships, and tanks) have been motivated by an
octopus' ability to match its colors to its surroundings (Bar-Cohen
2006
). With the
advent of modern computing technology, electronics, and nanotechnology, these
bio-inspired systems have become increasingly more complex and higher per-
formance. For example, McGary et al. (
2006
) and Liu (
2007
) have fabricated
artificial hair cell arrays for magnetostrictive acoustic sensing and fluid flow drag
force sensing, respectively. Other examples include bio-inspired auto-adaptive and
autonomous engineering systems (Tomizuka et al.
2007
), plant-inspired actuators
(Philen et al.
2007
), phospholipids, and microfluidic membranes (Horsley et al.
2008
), among many others (Loh et al.
2009
; Li et al.
2004
; Kao et al.
2007
; Lin
and Sodano
2009
).
Instead of presenting an exhaustive review of bio-inspired sensing systems, this
topic's chapter uses select examples of published works to highlight the breadth of
cutting-edge research. In particular, this chapter focuses on three different types of
bio-inspired sensors for SHM. First, Sect.
11.2
presents bio-inspired algorithms for
SHM. These algorithms could be used with current sensor networks for detecting
damage or sensor faults. Second, Sect.
11.3
discusses robotic sensors that mimic
the functionality of various creatures. Like geckos, these sensors could crawl on
various structural surfaces and collect information from locations inaccessible to
inspectors. Then, Sect.
11.4
highlights recent advances in designing conformable
sensors based on nanotechnology. These thin films could be coated onto structural
surfaces, and like skin, be able to detect damage over large spatial areas. This
chapter concludes with a brief summary and discussion of future trends and needs.
11.2 Bio-Inspired Computational Tools
The development of various data management, signal processing, and damage
detection algorithms has been inspired by biology. One particular prominent area
is computational methods inspired by the biological immune system (BIS). In
particular, BIS has provided a conceptual basis for deriving an artificial immune
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