Computed Tomography based Process Control of Composite Structures for In-service Defects

Abstract

In this study, Computed Tomography (CT) is employed to characterize service defects in polymer composites, paying particular attention to the influence of density and the effects of inclusion waviness and its distribution to the effective stiffnessof composites. Laminated composites, fabricated with varying densities and varying thicknesses, are subjected to low loading damage at various energy levels. X Ray CT is used to observe in plane matrix distribution and overall dark line indication propagation. CT is exploited to examine the through thickness matrix distribution and 3D dark line indication damage pattern. It is revealed that less fiber volume ratio act as crack initiation zones due to the presence of weak resin-rich pockets around fibers. Denser and unevenly distributed fiber volume ratio has shown more dark line indication (delamination) for various loading at different service hours. An appropriate density mapping using CT number and attenuation distributions are obtained from the fatigue test of specimen and flight test data of rotary wing blade to assess their safety and structural reliability.