Rapid prediction of compression after impact properties of composite structures: An equivalent strategy for impact damage

Abstract

Combined with the results of finite element simulation and experimental ultrasonic C-scan, a phenomenological-based equivalent impact damage finite element model was proposed and established to rapidly predict the damage evolution and buckling deformation of composite structures in compression after impact. An image recognition technology was adopted to divide the impact damage of composite laminates and stiffened panels into different regions, and a damage equivalent was conducted based on the measured impact damage size and morphology. Additionally, the material stiffness and strength parameters in different damage equivalent regions were reduced appropriately by different degrees. The impact pit deformation was equivalent to the element node offset in the corresponding area of the model, and the interface delamination and debonding were equivalent to the voids without elements. The equivalent impact damage model was applied to evaluate the buckling behavior and compressive strength after impact for laminates and stiffened panels using ABAQUS software. Moreover, a three-dimensional damage model considering the interaction of interlaminar delamination damage and interlaminar matrix and fiber damage was introduced to characterize the damage initiation, evolution, and extension behaviors of different damage modes. The comparative analysis indicated that the buckling and failure modes and compression after the impact strength simulated using the equivalent model were identical to the experimental results and had high correlation. This confirmed the accuracy, effectiveness, and applicability of the established equivalent impact damage model in predicting the compression buckling as well as residual strength and fracture modes for composite laminate and stiffened panel with simultaneous multi-zone impact damage.