Low-Velocity Impact Response and Ultrasonic NDE of Woven Carbon/ Epoxy—Nanoclay Nanocomposites

Abstract

In the present study, Nanomer® I-28E, organically modified montmorillonite nanoclay supplied by Nanocor Inc., was used to modify SC-15, a toughened epoxy system using sonication route. Different weight percentage ranging from 1—3% of nanoclay was used. The modified epoxy was then used to fabricate 15-layer plain weave carbon/epoxy composite laminates using a vacuum assisted resin transfer molding (VARTM) method. Samples of size 100 × 100 mm were cut from the laminates and were subjected to low-velocity impact loading using an instrumented drop-weight system (Dynatup Model 8210) at three different energy levels of 10, 20 and 30 J. Transient response of the samples was recorded and analyzed in terms to load-energy vs time relations. Impact damage was characterized by utilizing an ultrasonic nondestructive evaluation system (c-scan). Results of the study indicate that the infusion of nanoclay in the system reduced the impact damage though the impact response in terms of the peak load remained mostly unaltered. Reduced damage size was attributed to increased stiffness and resistance to damage progression of the nanophased laminates.