Free Vibration of Symmetric Cross-Ply Laminated Cylindrical Helical Springs

The first three free vibration frequencies of symmetric cross-ply laminated cylindrical helical springs with square section and fixed-fixed ends are theoretically computed based on the transfer matrix method. The rotary inertia, shear and axial deformation effects are taken into account in the solution. A parametric study is performed. to analyze the effects of the ratio of the extensional modulus to the shearing modulus, helix pitch angle and the number of active turns on the natural frequencies of such springs. The results are given in graphical forms.