Analytical investigation of fiber-orientation dependent stresses in a thick stiffened fiber-reinforced composite beam on simple supports

Fiber orientation dependent stresses in a thick, stiffened composite beam on simple supports are investigated analytically using a scalar potential field expressed in terms of displacement components of plane elasticity. The potential field of the present mixed-boundary-value problem is obtained by solving a single partial differential equation of equilibrium, which is then used to derive the expressions of relevant displacement and stress components in terms of Fourier series. Investigations are carried out for both the cases of lateral and axial stiffeners at the opposing ends of the beam. Two limiting cases of fiber orientation are considered for a number of fiber reinforced composite materials with a wide range of beam aspect ratio. The present analysis verifies the fiber orientation to be one of the important design variables not only for thick beams but also for moderately long beams, especially when the ends of the beam are stiffened.