“…Based on nonlocal beam theory, the static bending, buckling, vibration, and wave properties of single-/double-walled CNTs have been studied systematically [17][18][19][20][21]. In recent years, the nonlocal mechanics of elastic nanobeams have undergone rapid progress, with a lot of newly-developed theories, e.g., strain-driven and stress-driven nonlocal integral elasticity theory [22][23][24], two-phase integral elasticity theory [25], nonlocal strain gradient elasticity theory [26][27][28], and modified nonlocal strain gradient elasticity theory [29,30].…”