Influence of variable porosity on the buckling behavior of CNT-reinforced composite beams using HSDT

The development of advanced nanocomposite materials requires innovative strategies to overcome stability challenges in lightweight structures. In this study, an analytical model based on Higher-Order Shear Deformation Theory (HSDT) and Hamilton’s principle is employed to investigate the buckling behavior of functionally graded carbon nanotube (CNT)-reinforced composite beams with varying porosity distributions. Three CNT dispersion patterns (uniform, X-type, and O-type) and five porosity types (uniform, symmetric-1, symmetric-2, asymmetric-1, and asymmetric-2) are examined. The results reveal that X-CNT distribution combined with symmetric-2 porosity significantly enhances critical buckling loads—with improvements of up to 20.2% compared to uniform porosity cases. The slenderness ratio (L/h) and porosity volume fraction are also found to strongly influence the structural stability. The proposed model shows excellent agreement with existing literature, validating its accuracy. The key contribution of this work lies in providing, for the first time, a comprehensive parametric study combining multiple porosity profiles and CNT distribution types to optimize buckling resistance. These findings offer valuable insights for the design of high-performance, lightweight structural components in aerospace, mechanical, and civil engineering applications.