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Printed sensor arrays are attractive for reliable, low-cost, and large-area mapping of structural systems. These sensor
arrays can be printed on flexible substrates or directly on monitored structural parts. This technology is sought for
continuous or on-demand real-time diagnosis and prognosis of complex structural components. In the past decade, many
innovative technologies and functional materials have been explored to develop printed electronics and sensors. For
example, an all-printed strain sensor array is a recent example of a low-cost, flexible and light-weight system that
provides a reliable method for monitoring the state of aircraft structural parts. Among all-printing techniques, screen and
inkjet printing methods are well suited for smaller-scale prototyping and have drawn much interest due to maturity of
printing procedures and availability of compatible inks and substrates. Screen printing relies on a mask (screen) to
transfer a pattern onto a substrate. Screen printing is widely used because of the high printing speed, large selection of
ink/substrate materials, and capability of making complex multilayer devices. The complexity of collecting signals from
a large number of sensors over a large area necessitates signal multiplexing electronics that need to be printed on flexible
substrate or structure. As a result, these components are subjected to same deformation, temperature and other
parameters for which sensor arrays are designed. The characteristics of these electronic components, such as transistors,
are affected by deformation and other environmental parameters which can lead to erroneous sensed parameters. The
manufacturing and functional challenges of the technology of printed sensor array systems for structural state monitoring
are the focus of this presentation. Specific examples of strain sensor arrays will be presented to highlight the technical
challenges.
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