Influence of variable scattering on the optimum winding angle of cylindrical laminated composites

Cylindrical laminated composites are generally made with a fibre winding angle equal to 55°. In this paper the authors show, by using reliability analysis of a [±alpha]n filament wound composite, that the optimum fibre winding angle can vary hugely with the scattering of some design variables. Studied structures are pressure vessels and axially loaded pressure pipes. The stresses are computed using the classical laminated membrane theory and the Tsai-Wu failure criterion is adopted as the limit state function of a ply. Numerical results show that the Youngʹs modulus of the matrix and the transverse strength of the ply are the most important design variables. The amplitude of the applied pressure and the axial force also modifies the optimum winding angle.