Free vibration of uniaxial composite cylindrical helical springs with circular section

The free vibration problem of unidirectional composite cylindrical helical springs is modelled theoretically as a continuous system considering the ro tary inertia, shear and axial deformation effects. The first order shear de formation theory is employed in the mathematical model. The 12 scalar ordin ary differential equations governing the free vibration behavior of cylindr ical helical springs made of an anisotropic material are solved simultaneou sly by the transfer matrix method. The overall transfer matrix of the helix is computed up to any desired accuracy by using the effective numerical al gorithm available in the literature. The theoretical results are verified w ith the reported values, which were obtained theoretically and experimental ly for straight beams and helical springs. A parametric study is performed to investigate the effects of the number of active coils, the helix pitch a ngle and material types on the first six natural frequencies of helical spr ings with circular section and fixed-fixed ends. (C) 2001 Academic Press.