A buckling model of fiber-reinforced composite lattice cylinders with the cutout imperfections

The lattice load-bearing cylinder structure, with its exceptional strength-to-weight ratio, holds great promise for application in aerospace engineering. To facilitate structural assembly or the embedding of electronic equipment, various types of cutout structures are often designed on the main load-bearing lattice cylinder. The existing theoretical research on the failure mechanism of lattice cylinders primarily focuses on regular structures without cutouts. When the lattice cylinder with cutouts undergoes buckling, the complexity of the ribs’ shape hinders the establishment of the energy function. An analysis of the mechanical performance of lattice cylinders with localized cutouts is undertaken. Based on the buckling patterns derived from simulation analyses, displacement function assumptions are formulated. A multi-failure analysis model is established for lattice cylinders with cutouts, revealing their underlying failure mechanisms. The validity of the theoretical model is confirmed through simulations and experiments. The study’s findings demonstrate the influence of cross-sectional size and helical angle on the type of failure. A three-dimensional failure mechanism diagram is constructed, bridging the gap in the theory of failure modes for this type of structure. The study delves into the correlation between the maximum critical loads and the dimensions of rectangular and circular beams that traverse the interstitial spaces within lattice cylinders characterized by cutouts. The bearing efficiency is also explored in the study, with the optimal geometric point being identified through mapping structural mass contours and following the optimal bearing efficiency trajectory. This approach broadens the design space and provides a theoretical basis for engineering applications.