Stress fields induced in fibre-reinforced composite laminate beams by torsion

A model of a fibre-reinforced composite laminate beam with sections of rectangular shape is presented and the stresses due to torsional moments are determined by an analytical solution. The technique followed is based on Sokolnikoffʹs approach in conjunction with the theory of anisotropic elasticity. The results derived permit the evaluation of the off-axis elastic constants for the material. The evaluation of 3-D stress distributions in sections characterized by various aspect ratios reveals the elastic coupling of stresses and strains due to torsion in these composite laminate beams. In addition, useful information gained from the study of the variation of the elastic properties as well as torsional rigidity for fibre-reinforced laminate beams leads to further knowledge for the stress and strain distributions over the whole beam.