Experimental and Numerical Investigation of the Mechanical Characteristics of Kevlar Composite Deployable Lenticular Tubes

Carbon fiber-reinforced plastics (CFRP) are widely used in deployable space structures due to their strength-to-weight ratio, yet their inherent brittleness and limited damage tolerance constrain their performance under large deformation. This study reports a new concept, the Kevlar composite deployable lenticular tube (CDLT), for improved toughness and reliable stowability. The buckling response of Kevlar CDLT under axial compression and torsion was characterized, and its stowability was verified through experiments and finite element analysis (FEA). Axial compression studies show that the load–displacement curve transitions from linear elastic to nonlinear deformation at the critical buckling load; meanwhile, local stress magnification occurs in the central arc region. Damage analysis further reveals that buckling instantaneously induces localized wrinkling and matrix failure. Torsional analysis shows that the CDLT exhibits an initially linear torque–twist response, governed by shear stiffness. However, once the critical torque is exceeded, torque decreases sharply due to localized collapse and overall buckling. Moreover, the outermost layers bear the highest stresses, whereas the inner layers remain comparatively uniform and less stressed. Furthermore, the influence of different layup sequences, ply numbers, and total thickness on the load-bearing capacities of CDLT was investigated, ultimately determining the optimal layup scheme. Finally, the stowability analysis demonstrates that the Kevlar CDLT, configured as a six-ply laminate with a total thickness of 0.72 mm, achieves an optimal balance between stiffness and flexibility. In this comparison, both the Kevlar and CFRP CDLTs employ identical lenticular cross-sectional geometries, fully consistent boundary conditions, the same overall laminate thickness (0.72 mm), and an identical stacking sequence of [45°/−45°/90°/90°/45°/−45°], with the material properties being the only variable. Under these strictly controlled conditions, the coiling torque of the Kevlar CDLT is reduced by at least 48% relative to that of the CFRP CDLT. This study preliminarily verifies the load-bearing capacity and stowability of novel Kevlar CDLTs, providing valuable guidance for the design of deployable space structures.