WINDING ANGLE EFFECT ON FRATURE BEHAVIOUR OF COMPOSITE TUBES UNDER DIFFERENT LOADING CONDITIONS

ABSTRACT:
 
Glass-fibers/plastic tubes are increasingly used in industrial environments where their strength, low weight, and corrosion resistance make them competitive with other materials. Filament winding process provides a mean of producing fiber-reinforced tubes in which the direction of fibers is closely controlled to give very high strength in preferred direction. The aim of this work is to investigate the effect of winding angle and number of layers on burst behavior of filament wound tubes manufactured by circumferential winding process. The tubes were tested to failure under longitudinal, hoop, and biaxial loading. Filament wound tubes was fabricated using E-glass-fibers/polyester at winding angles ranging from 35° to 85° and number of layers 8 and 14. The results of internal pressure hoop test showed a significant rise in the hoop burst stress and initial modulus with increasing winding angle, while the strain to failure decreased. The high winding angle tubes, 60° and above, failed by catastrophic fiber fracture. Tubes with lower winding angle were characterized by “Initial failure” associated by longitudinal resin cracking that lead to a subsequent degradation in tube modulus. The uses of rubber liner during tests lead to a significant increase in maximum stress and strain to failure. The elastic properties were measured in longitudinal and hoop directions and a stress/strain response was obtained for each tube. The results were found to be consistence with the current theories for filament wound angle ply composites.