Transient Response of Rotating Multiscale Carbon Nanotube/Carbon Fiber Annular Plates for High-Impact Weightlifting Applications

This study explores the transient dynamic response of rotating hybrid annular plates designed for highimpact weightlifting applications, subjected to mechanical shock. The proposed structure is modeled as a multi-scale three-phase composite, consisting of a polymer matrix reinforced with carbon nanotube (CNT) nanoparticles and unidirectional carbon fibers (CF). The Eshelby–Mori–Tanaka scheme is adopted to incorporate the effects of CNT agglomeration, enabling accurate prediction of the enhanced isotropic properties of the nanocomposite. The governing equations, derived via First-Order Shear Deformation Theory (FSDT) and Hamilton’s principle, are solved using the finite element method combined with the Newmark time integration scheme. A comprehensive parametric study is conducted to assess the influence of CNT mass fraction, distribution, agglomeration, CF volume fraction, fiber orientation, geometrical configuration, and boundary conditions on the dynamic performance of the annular plate. Results indicate that the synergistic use of CNTs and CFs significantly enhances the plate’s stiffness and impact resistance. Notably, at 0.1 CF volume fraction, the central deflection under shock loading is reduced by 27.7% compared to a CNT-only system (1% CNT). A combined reinforcement of CNTs and CFs leads to a 49.2% reduction in deflection. Maximum performance is observed at 0° fiber orientation, while deflection increases by 222% at 45°, highlighting the critical role of fiber alignment in weightlifting-specific impact scenarios. The influence of the CNT distribution pattern on the dynamic response is highly dependent on the CF orientation. Variations in the CF angle not only amplify the effect of the CNT distribution but also alter which specific distribution pattern yields the optimal structural performance.