Finite element modelling and experimental validation of oblique compression in thin-walled carbon fiber-reinforced composite tubes

To investigate the mechanical response and energy absorption behaviour of carbon fiber-reinforced polymer (CFRP) thin-walled tubes under oblique compression, CFRP thin-walled tubes with different wall thicknesses were selected as the research objects. A specialized angle-fixed mould was designed to ensure the stability of oblique compression tests, thereby resolving the issue of specimen slippage associated with conventional oblique loading., and conducts quasi-static compression tests at 0°, 15°, 30° and 45° to analyze the effects of loading angle and wall thickness on their failure modes and impact resistance. Meanwhile, a finite element model is established in ABAQUS, which adopts the two-dimensional Hashin failure criterion to characterize the progressive intra-layer failure of CFRP and uses cohesive elements to simulate interlaminar delamination damage. The reliability of the model was validated against experimental results. The results indicate that the mould enables stable oblique compression testing, and the deformation patterns, load-displacement curves, and impact resistance indicators (such as peak crushing force and specific energy absorption) of the constructed model show high agreement with the experiments, with errors all controlled within 10%. The failure modes of CFRP thin-walled tubes evolve in a systematic manner with the loading angle. Axial compression is dominated by progressive buckling, whilst oblique compression, as the angle increases, successively exhibits local buckling and fiber stacking, local buckling and delamination, and shear-dominated lateral cracking.