Effects of Defects in a New Form of Affordable Composite Materials-Rod Reinforcement

A pultruded rod reinforced composite which can eliminate presence of fiber waviness and reduce cost of laminate manufacturing has become a focus interest to aircraft manufacturers. Due to its characteristics of rod layer, conventional analysis which use the smeared properties across the entire rod layer fails to predict the structural response of this rod reinforced laminates. A closed-form expression was derived and a finite element analysis was conducted for predicting the critical buckling load for this type of laminates with a damage. Damage considered include broken rods, rods split vertically and horizontally, and delamination between the rod layer and angle plies. It is concluded that damages with rods split horizontally and a delamination can reduce the buckling load. For the rods broken, the buckling load will be reduced if a broken space is included. However, the buckling load remains unchanged if rods split vertically.