Parametric investigation of functionally gradient wave springs designed for additive manufacturing

Abstract

Functionality and design of mechanical springs are simple and limited due to manufacturing constraints of conventional fabrication methods being used for making helical and wave springs. In recent era, design for additive manufacturing has proven its great worth to design and manufacture optimal, complex as well as intricate structures with better mechanical and lightweigting properties. This study aims to investigate the mechanical behavior of functionally gradient wave springs as a function of variation in thickness and morphology of each wave. Functionally gradient wave springs incorporated with different morphology and cross-sections including circular, rectangular and combination of both were designed and printed by keeping mass and height constant to investigate their mechanical properties. Loading–unloading experimentation was conducted within the elastic range (90% of compressible distance) in order to study energy absorption/loss, load-bearing capacity and stiffness of all designs. The experimental results were validated by finite element anaylsis (FEA) by providing the identical boundary conditions of experimental setup. The results revealed that the stiffness of wave spring having rectangular cross-section is increased significantly, while energy absorption is almost 90% increased due to circular cross-section of waves. Overall, the design with combination of round and rectangular cross-sectional waves has better stiffness and energy absorption properties. For further investigation of mechanical properties due to variation in cross-section of waves, more designs including semi-circular and filleted waves were designed, and FEA of those showed that 786 N of load-bearing capacity is achieved in the wave spring having semicircular cross-section of waves which is double than the wave spring having variable circular cross-section of waves.