Nonlinear analysis of functionally graded fiber reinforced composite laminated beams in hygrothermal environments, Part II: Numerical results

In this part, the extensive parametric studies performed are reported and numerical results are presented for the nonlinear vibration, nonlinear bending and thermal postbuckling of uniformly distributed and functionally graded fiber reinforced cross-ply and angle-ply laminated beams resting on Pasternak elastic foundations under different sets of hygrothermal environmental conditions. The numerical results reveal that a functionally graded reinforcement has a significant effect on the nonlinear vibration characteristics, nonlinear bending behaviors, and thermal postbuckling behaviors of fiber reinforced composite (FRC) laminated beams. The results show that the temperature/moisture variation has a moderately effect on the natural frequencies of the FRC laminated beam, but only has a small effect on the nonlinear to linear frequency ratios of the same beam. In contrast, it has a significant effect on the nonlinear bending load-deflection curves of the FRC laminated beam. The results confirm that the thermal postbuckling equilibrium path of mid-plane unsymmetric FG-FRC laminated beams with immovable simply supported end conditions is no longer the bifurcation type.