Analytical interlaminar stresses of composite laminated beams with orthotropic tapered layers

Abstract

Innovative manufacturing methodologies offer opportunity to fabricate tapered composite laminates without layer terminations. However, the complex mechanical behaviour of tapered composite beams has yet to be studied. We introduce an accurate cost-efficient analytical method in line with Timoshenko theory to predict transverse stresses of composite laminated beams comprising orthotropic tapered layers under transverse loading, including pressure loads and transverse body forces. The transverse stress components are derived by introducing taper into the lamina constitutive relation followed by Cauchy stress equilibrium. The main conclusions of this study include: (i) transverse stresses are fully coupled with the internal forces and their derivatives; (ii) transverse stresses can be discontinuous through the thickness; (iii) Classical Laminate Theory underestimates transverse stress magnitudes of composite laminated beams. Results are validated with 2D and 3D solid-like finite element analyses inferring high levels of accuracy for the transverse stresses valid up to 8° of taper.