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The field of structural health monitoring (SHM) has made significant contributions in the field of prognosis and damage
detection in the past decade. The advantageous use of this technology has not been integrated into operational structures
to prevent damage from propagating or to heal injured regions under real time loading conditions. Rather, current
systems relay this information to a central processor or human operator, who then determines a course of action such as
altering the mission or scheduling repair maintenance. Biological systems exhibit advanced sensory and healing traits
that can be applied to the design of material systems. For instance, bone is the major structural component in
vertebrates; however, unlike modern structural materials, bone has many properties that make it effective for arresting
the propagation of cracks and subsequent healing of the fractured area. The foremost goal for the development of future
adaptive structures is to mimic biological systems, similar to bone, such that the material system can detect damage and
deploy defensive traits to impede damage from propagating, thus preventing catastrophic failure while in operation.
After sensing and stalling the propagation of damage, the structure must then be repaired autonomously using self
healing mechanisms motivated by biological systems. Here a novel autonomous system is developed using shape
memory polymers (SMPs), that employs an optical fiber network as both a damage detection sensor and a network to
deliver stimulus to the damage site initiating adaptation and healing. In the presence of damage the fiber optic fractures
allowing a high power laser diode to deposit a controlled level of thermal energy at the fractured sight locally reducing the modulus and blunting the crack tip, which significantly slows the crack growth rate. By applying a pre-induced strain field and utilizing the shape memory recovery effect, thermal energy can be deployed to close the crack and return the system to its original operating state. The entire system will effectively detect, self toughen, and subsequently heal damage as biological materials such as bone does.
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