Morphological analysis of as-manufactured filament wound composite cylinders using contact and non-contact inspection methods

Filament winding is a versatile technique for producing pressure vessels throughout the deposition of continuous fiber filaments on a rotating mandrel under determined conditions. Considering the relative safety requirements, these structures are expected to demonstrate high load carrying capacity to ensure the proper storage and transportation of pressurized fuels. Therefore, the quality of the manufactured product and the identification of defects, both structural and morphological, is essential. In the present work, measurements have been carried out in as-manufactured helicoidally filament wound cylinders, made of carbon fiber reinforced polymer, for identifying their morphological characteristics and the presence of variations of the winding angle and gaps or voids. A contact-based ultrasound system is employed to measure the wall thickness and to evaluate the existence of gaps between the layers through the thickness. Furthermore, a non-contact vision-based system is employed to scan and measure the variability of the winding angle. These techniques were applied to 2 identically fabricated filament wound products to identify the repeatability of the manufacturing process as well. The results revealed a deviation between the designed and manufactured product in terms of wall thickness and the actual filament winding angle and a strong variation of both through the various zones of interest through the length and the circumference.