Experimental and Numerical Analysis of Ballistic Impact Damage of Helicopter Composite Tail Drive Shafts

ABSTRACT The composite tail drive shaft of the helicopter offers the advantages of high power density, excellent vibration damping characteristics, and superior energy absorption properties. However, it is vulnerable to ballistic impact threats under operational conditions. In this study, ballistic impact tests and finite element modeling were employed to assess and analyze the ballistic impact damage of the composite tail drive shaft. To simulate the intra‐laminar high‐velocity impact damage behavior of composites, a dynamic damage model was developed based on continuum damage mechanics and 3D‐Hashin criterion. The cohesive zone model was used to characterize the inter‐laminar damage initiation and propagation of composites. Additionally, to account for the strengthening effects caused by high strain rates, the strain rate correlation coefficients were introduced to modify the constitutive model. The bullet's residual velocity, the impact process, and the damage morphology of composites obtained from numerical simulations and impact tests demonstrate a high degree of consistency, effectively validating the reliability of the simulation model. Subsequently, using the validated simulation model, the detailed impact damage process and failure characteristics under different typical impact conditions were analyzed and compared. Delamination, matrix tensile damage, and fiber tensile damage were identified as the dominant failure modes, with edge impacts causing more severe damage than central impacts. Furthermore, the effects of offset distance and incident angle on the ballistic impact damage were investigated, revealing significant non‐monotonic effects on material removal volume and the bullet's residual velocity.