Large deflections of elastic composite circular springs under uniaxial tension

Closed-form solutions from elliptic integrals with the usual assumption of inextensional elastica are derived for large deflections of specially ortho tropic and mid-surface symmetric laminated circular springs in the form of ring under in-plane and uniaxial tension. A numerical procedure including t he effects of flexural bending, mid-surface stretching and through-the-thic kness parabolic distribution of transverse shear deformations has also been applied to study the non-linear problem. Comparison studies of the results obtained from the two methods are made with experimental data and the resu lts are found to be in good agreement as far as the present investigation i s concerned. Non-linear spring behavior are obtained and verified by experi mental testing. Three E-glass woven cloth/epoxy composite springs with diff erent aspect ratios are tested, The influence of elastic to shear modulus r atios and radius to thickness ratios to deformation are considered and disc ussed. (C) 1999 Elsevier Science Ltd. All rights reserved.