The effect of reinforcement-length of carbon fiber reinforced bonding composites on circular tubes under flexural condition

This paper presents an experimental investigation on flexural performance of carbon fiber reinforced bonding composite circular tubes with different length of reinforcing pieces. Four kinds of composites bonded tubes with different reinforcing pieces length 20mm, 30mm, 40mm and 50mm were carried out. The flexural strength and modulus of bonged composite samples tested were investigated. The experiment result indicates that the length of reinforcing pieces has some effects on the flexural performance of bonding composite circle tubes. The average flexural strengths of samples reinforced 20mm, reinforced 30mm, reinforced 40mm and reinforced 50mm are 41%, 45%, 49% and 51% of average flexural strength of boned samples without bonding, respectively. The bonding strength will improve when the length of reinforcing pieces increases. The modulus does not change when reinforcing length was greater or equal than 30mm. The main typical failure modes of tested specimens are adhesive cohesive failure and interlamination failure between prepreg and adhesive film.