Early-stage damage detection could provide better reliability and performance and
a longer lifetime of materials while reducing maintenance time of a variety of structures and systems.
We investigate the early-stage damage formation and damage evolution in advanced multifunctional
laminated aerospace composites embedded with a very small amount of carbon nanotubes
(CNTs) in the matrix material and short carbon fibers along the Z-direction to reinforce the
interlaminar interfaces. The three-dimensional (3-D) conductive network formed by the CNTs and
the flocked carbon fibers allows for sensitive in-situ damage detection in materials in addition to
providing improved mechanical properties such as superior fracture toughness for damage tolerance.
We optimize several parameters such as fiber length, diameter, and density to generate an effective
3-D electrical conductive network, and characterize the responses of these composites under
mechanical loading to investigate damage formation and evolution, advancing science and
technology towards superior damage-tolerant and zero-maintenance structural materials.
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