Natural thickness redistribution and axial buckling of non-geodesic continuous variable-angle filament-wound composite tubes

Abstract

The development of deepwater and offshore engineering has imposed increasingly stringent requirements on the axial-compression stability and load-carrying efficiency of lightweight composite tubular structures. Although continuous variable-angle filament winding enables spatial tailoring of fiber orientations, variations in winding angle also alter trajectory spacing, fiber coverage, and wall-thickness distribution. The effects of this manufacturing-induced nonuniformity on axial buckling and ultimate load-carrying capacity remain insufficiently understood. In this study, a continuous fiber-angle field was prescribed to generate frictionally stable non-geodesic winding trajectories. The corresponding equivalent natural-thickness distribution induced by fiber coverage variations was then determined. The resulting fiber-angle and thickness fields were jointly mapped onto a finite element model and validated against published benchmarks. Within the angle range of 55°-61° at constant thickness, angle continuity changes the critical buckling load by only 0.17%, whereas natural-thickness redistribution increases it by 25.49%. After mass normalization, the improvement remains 9.40%. For the baseline imperfect models, the continuous-angle-natural-thickness configuration exhibits a 39.26% higher peak load than the engineering reference configuration. These results show that path-induced thickness redistribution and the resulting axial stiffness gradient enhance load-carrying capacity while reducing imperfection sensitivity.