Mechanical Behavior of Carbon Nanotube-Reinforced Microtubes with Diverse Cross-Sections Using Modified Strain Gradient Theory

This study proposes closed-form solutions for the mechanical behavior of microtubes, including bending, buckling, and vibration, based on the modified strain gradient theory. The microtubes are reinforced with different patterns of carbon nanotubes across their cross-sections. Continuous, layer-wise gradients can characterize the distributions of reinforcing materials, thereby improving structural performance. The microtubes, having two main cross-sectional areas, which are ring and oval shapes at the outer radius, are examined under the action of different types of external loadings. For microstructural design, the deflection, stresses, critical buckling load, and natural frequency of such microtubes are calculated and analyzed with respect to various influences of size, material composition, tubular shape, and loading type. The findings show that increasing the amount of carbon nanotubes in microtubes significantly increases their strength, thereby reducing deflection and increasing the buckling load and natural frequency.