Recovery of Interlaminar Tensile Stresses in Curved Laminates Subject to Biaxial Flexure: The Case of an Elastically Induced Curvature Purposely Misaligned with the Principal Directions of Initial Curvature

Many literature contributions deal with the evaluation at FE post-processing stage of the interlaminar normal stress distribution in moderately thick single or doubly curved laminates subject to flexure, based on through-the-thickness equilibrium relations. Most of the contributions, however, discuss test cases in which the principal directions of the load-induced elastic curvatures are aligned with the principal directions of the initial curvature; this condition is not general. In the present work, a simple post-processing methodology for the recovery of the interlaminar tensile stress is presented.

The procedure retrieves the Interlaminar Tensile Stresses (ILTS) distribution in a doubly curved laminate modelled through common wise quadrilateral shell Finite Elements and is based on customary FE sub-model which inputs are the displacements and rotation calculated on the shell structure. At the moment the sub-model can't retrieves Interlaminar Shear Stresses but can be further enhanced to do it.

In this paper the methodology is successfully applied to an open thin walled profile in torsion test case, in which the principal directions of elastic curvature are strongly misaligned with the principal directions of initial curvature.