Local effects in stiffened composite tubes under generalized plane deformation

A two-dimensional, curvilinear, isoparametric, finite element is used to study local curvatures and interlaminar stresses in laminated composite tubes with laminated stiffeners running the length of the tube. The generalized plane problem is analyzed by considering a generic transverse cross section of the stiffened tube to provide three-dimensional states of stress. Discrete layers of the tube and the stiffener are modeled explicitly, providing an accurate and detailed representation of local effects. Cross-ply, angle-ply and general laminate configurations are studied for axial, torsional and internal pressure loadings that are constant along the length of the tube. It is shown that local curvatures and interlaminar stresses can be significant and variable and depend upon the laminate configuration and loading conditions.