Low-velocity impact and compression-after-impact behaviors of twill woven carbon fiber/glass fiber hybrid composite laminates with flame retardant epoxy resin

Composite structures suffer from significant residual strength reduction as a result of invisible damage caused by impacts, which can cause severe harm without any prior warning. Fibers play a crucial role in improving the impact resistance of composite materials by providing strength, toughness, and energy absorption. This work explores the dynamic response and residual compressive strength of composite laminates reinforced with twill woven carbon fiber, glass fiber, and carbon fiber /glass fiber hybrid, subjected to low-velocity impact (LVI) and compression-after-impact (CAI) testing. First, the performance of woven carbon fiber composite laminates infused with flame retardant epoxy resin and general epoxy resin was studied. The results indicated a lower load-bearing capacity and elongation of the former. To enhance the impact resistance of the laminates, we explored the effects of incorporating glass fibers into the woven carbon fiber composite laminates. Our findings demonstrated that the introduction of glass fibers alteres the impact damage mode of the laminates and effectively improved their impact resistance and CAI strength. Further, several techniques were adopted to characterize the corresponding damage morphologies and failure mechanisms of the woven carbon fiber composite laminates, which provides valuable insights for their structural design and performance improvement.