Wave spring stiffness and improved design

Abstract

Wave springs are typically used if the radial space is limited. The spring has not gained as much practical use as the alternative Belleville spring or helical spring. This can to some extent be due to the non-linear force-deflection relationship. In the present paper the wave springs are investigated numerically, using a full 3D finite element analysis, primarily for finding the force-deflection curves. It is shown that we can obtain linear, bi-linear or general non-linear characteristics by changing the geometry. The found numerical stiffness is compared to analytical expressions found in the literature. Further it is investigated how the axial loading influences the radial displacement and the associated cross-sectional rotation. In the numerical evaluation it is found that the spring material, for a standard spring design, is unevenly loaded. Simple design modification can lead to significantly better designs. Relating the average von Mises stress to the maximum von Mises stress in the spring shows for a single design case, that improvement of more than $220\mathrm{\%}$ is possible.