Finite Element Analysis of Composite Laminated Plates under Combined Thermo Mechanical Loading: Effect of Layup Sequence and Temperature Gradient on Deflection, Stress Distribution, and Free Vibration Response

This paper presents a comprehensive finite element investigation into the structural behaviour of composite laminated plates subjected to combined thermomechanical loading. Four fibrereinforced polymer (FRP) laminate configurations [0/90/0/90]s, [±45]₂s, [0/±45/90]s, and [90/0/90/0]s fabricated from carbon/epoxy (CFRP), glass/epoxy (GFRP), and Kevlar/epoxy composites are analysed using ANSYS Mechanical 2024 R2 with SHELL281 eightnode layered shell elements. The effect of temperature gradient (ΔT = 0°C, 50°C, 100°C) on central deflection, Von Mises stress, interlaminar shear stress, and free vibration natural frequencies is quantified. Mesh convergence analysis confirms solution independence at a 5 mm element size with 1764 elements. Results show that the [0/90/0/90]s crossply layup exhibits the minimum central deflection and lowest interlaminar shear stress under all loading conditions. A 100°C thermal gradient increases maximum deflection by 82.4% compared to pure mechanical loading. Modal analysis reveals that fibre orientation angle significantly influences natural frequency, with [0/90/0/90]s achieving the highest fundamental frequency of 48.6 Hz. Parametric results and failure index predictions using the TsaiWu failure criterion are presented for all laminate configurations.