Nonlinear Deformation Analysis of Sandwich Timoshenko Beams with Carbon Nanotube Reinforced Face Sheets and Re-Entrant Core Using GDQ Method

In this research, the nonlinear bending behavior of sandwich beams with auxetic re-entrant cores and carbon nanotube-reinforced (CNT) face sheets are investigated using the von Kármán strain theory and the Generalized Differential Quadrature (GDQ) method. The results demonstrate the high accuracy of the GDQ method in solving nonlinear problems with a minimal number of grid points. Validation is performed by comparing the obtained results with those reported in previous studies. The findings indicate that CNT-reinforced composite beams exhibit superior bending performance compared to sandwich beams with re-entrant cores and conventional composite face sheets. Furthermore, a parametric study on the core geometry reveals that optimal bending performance is achieved when the interior angle (θ) of the core is approximately 0 to 2 degrees, and the nondimensional auxetic parameter η_1 is minimized. This study highlights the significance of nonlinear analysis, particularly for long and slender beams.