Study of Impact Damage of Composite Laminates Using Five-Point Bending

The low-velocity impact of composite laminates can induce high transverse shear strains, resulting in severe damage within the laminate. This type of damage may be studied by the use of a five-point bending test configuration. An investigation of composite laminate failure induced by transverse shear strains is described in the present paper. In order to gain insight into the representation of low-velocity impact damage by the five-point bending configuration, low-velocity impact tests were performed. Five-point bending tests were also perforned, producing transverse shear cracks, delaminations, and other types of failures. Since transverse shear strain causes failure under conditions of low-velocity impact, a comparison between the results of the five-point bending tests and established results of impact tests is presented, showing that both types of tests produce the same failure modes. Also, AS4-PEEK graphite-thermoplastic is shown to be more resistant to five-point bending damage than is AS4-3502 graphite-epoxy.