Buckling behavior of composite cylindrical shells with honeycomb sandwich structure

This paper investigates the buckling behavior of carbon fiber reinforced polymer honeycomb sandwich cylindrical shells (HCSs) under external pressure, with emphasis on the buckling response and the effects of geometric parameters. Two groups of HCS specimens with identical mass but different honeycomb cell sizes were designed and fabricated. Hydrostatic pressure tests were conducted to obtain their ultimate buckling loads. Additionally, a finite element model was developed in ABAQUS, and its accuracy was validated against the experimental results. The validated model was further employed to reveal the damage evolution process and the effects of key geometric parameters on buckling capacity. The results show good agreement between the experimental and numerical results, indicating that the proposed model can accurately capture the buckling characteristics of HCSs under external pressure. The final failure of the structure results from the coupled effects of progressive fiber damage, matrix damage, and structural instability. Compared with an equal-mass single-layer composite cylindrical shell (SCS), the HCS exhibits a higher ultimate buckling load and superior buckling resistance. These findings provide useful guidance for the design and optimization of composite honeycomb sandwich cylindrical shells used in marine pressure structures.