An experimental investigation on the low-velocity impact response of carbon–aramid/epoxy hybrid composite laminates

In the current study, the low-velocity impact response of hybrid-laminated composites based on the twill woven fabrics was investigated experimentally. The following five different types of carbon–aramid/epoxy hybrid laminates were produced and tested, (a) two types of interply hybrid, (b) two types of sandwich-like interply hybrid, and (c) intraply hybrid. Non-hybrid carbon and aramid twill woven laminates were also tested for comparison. The effects of the hybrid structure on the impact properties such as the peak load, the ductility index, and damage area were discussed. The impact damage resistances of specimens were evaluated by comparing damage images taken from both the impacted and the non-impacted surface. The damage and failure mechanisms were analyzed from the impact damage morphologies using ultrasonic C-scan and three-coordinate measuring device. Under the same impact energies, the interply hybrid laminates with carbon fabric on the impact surface have higher impact damage resistance. It can be concluded that placing of high stiffness carbon fabric at highly stressed regions as reinforcement would result in enhanced properties, and the damage tolerance performance of composites with interply hybrid structure are better than those of other hybrid composites.