ABSTRACT: Sensors embedded in structural
composites have been a topic of research in recent years.
Embedded sensors can be used to monitor and optimize
the manufacturing process, to monitor performance during
use, and for structural health monitoring in high-
performance applications. For several years, embedded
optical fibers were the predominant type of sensor. There
are well-known reasons that optical fiber sensors have not
yet been fully embraced in industry including the cost of
equipment and sensors, the fragility of the optical fiber
itself, and the need to provide ingress and egress from the
structure. Recent work by the authors and others has
produced prototype wireless electronic sensors of various
types that address these shortcomings.
The US Office of Naval Research is funding a multi-
disciplinary team to consolidate progress made in earlier
programs towards self-contained microsensors to be
embedded in a composite structure and queried using
methods that do not require physical connections. The
sensors are to be left in place for the lifetime of the
structure, are powered by the querying apparatus, and
require no penetrations through the surface of the structure.
This paper describes the integrated approach taken to
realize the goal of an interrogatable strain rosette that is
embedded 0.25 below the surface of a graphite composite
plate. It also describes the progress to date of the sensor
system itself.