Low-velocity impact resistance behaviors of bio-inspired helicoidal composite laminates with non-linear rotation angle based layups

Abstract Through evolutionary process, special biological structures (e.g. micro- or macro-scale helicoidal laminated structures) are formed naturally to resist natural enemies. With some bionic inspirations, anti-impact design of composite laminates applied for aerospace, vehicle, etc. can be stimulated by helicoidal biological structures. In the work, the Non-Linear Rotation Angle (NLRA) based bio-inspired helicoidal layups are designed to enhance the impact resistance capacity of composite laminate. Four types of helicoidal configurations are proposed including Quasi-isotropic (QI), Helicoidal-Recursive (HR), Helicoidal-Exponential (HE) and Helicoidal-Semicircular (HS). The failure behaviors of material are investigated with the progressive damage model. Damage development of fiber, matrix and delamination interface is conducted with stress-based failure criteria, fracture energy criteria and stiffness degradation method. The impact damage behaviors of carbon/epoxy composite laminates with QI and NLRA helicoidal layups are studied and compared. Further, effects of coefficients in each layup formula are discussed. Numerical results show that predicted load-time curve and damage modes for QI correlate well with experimental results. It is revealed that both the maximum resistance load and threshold load for the initial matrix damage and delamination increase with the increase of each coefficient. As compared with QI layup, HR and HE layups with large rotation angles can improve the capacity of impact resistance.