Contact Dynamics and Stress Field of Fluid-Conveying GRC Nanotubes

Fluid-conveying nanotubes play key roles in micro-nano electromechanical systems. The contact dynamic response and stress field of the fluid-conveying graphene reinforced composite (GRC) nanotube under lateral low-velocity impact are studied. The size-dependent models considering slip flow, nonlocal stress and strain gradient effect are established. The governing equations of flow-inducing post buckling and contact vibration are derived based on a refined beam theory, in which the post-buckling equilibrium provides the initial configuration for the impact vibration analysis. A computation mode of two-step perturbation-Galerkin truncation-Runge-Kutta method is developed to study the contact dynamic responses. Through the convergence analysis, the truncation terms required to ensure the accuracy are obtained. The contact force curves and the midspan displacement time history curves are acquired, and the dynamic snap-through instability behaviors of the nanotube in the flow-inducing post-buckling state are revealed. Also, the stress field in the impact process is obtained to provide theoretical results to guide the strength design. Numerical results reveal the dual influence law of nonlocal stress and strain gradient on the contact dynamic response and stress field and provide the flow velocity range sensitive to the nano effects.