Polymer Engineering Faculty Research

A Novel Economical Method to Improve the Toughness of Carbon/Epoxy Long Fiber Components by the Integration of Tow Loops Cores

Erol Sancaktar, The University of Akron


In this research, solid and sandwich carbon/epoxy composite plates were developed, fabricated, and tested at two different crosshead speeds of 10 and 500 mm/min, under monotonic penetration tests, which perpendicularly applied a concentrated load to the simply supported plates. The cores of sandwich plates were made of carbon prepreg (with epoxy resin), as well as glass tow loops (without resin). The plates’ lay-up configuration sequence was {[0/90]n }s , where n was 1, 2 or 4. The objectives of this study were to determine the general sandwich plate behavior, as well as to analyze the effects of the test rate, the number of internal loops and the number of plate facesheet plies on the failure mode, ultimate plate deflection, ultimate load, plate’s flexural rigidity, plate’s absorbed energy, and the extent of damage. The use of carbon fiber prepreg tow loops impregnated with epoxy resin, as well as dry glass tow loops without any resin provided information on the effect of resin presence in these core layers. For these purposes, the load versus plate deflection data were recorded and analyzed. The load-deflection curves were used to interpret the plate behavior in terms of flexural rigidity and absorbed energy. The plate’s absorbed energy values at both speeds were used to assist in the dynamic response analysis. The results of our experiments revealed that, at higher loading rates, the internal loops of carbon prepreg material with epoxy resin enhanced the energy absorption capability of the plates more significantly than those containing dry glass tow loops without resin impregnation.