Theoretical and experimental study on a novel 3D lattice-structured shock-absorption device produced by digital light processing additive manufacturing

Abstract

Digital light processing (DLP) additive manufactured technology uses ultraviolet light to solidify and shape liquid polymers, enabling the creation of intricate devices with viscoelastic properties. In this study, a 3D lattice-structured shock-absorption device using DLP on polyurethane is produced. To better characterize the mechanical behaviors of the device, experimental tests for the additive manufactured device samples are performed and the frequency-dependent force-displacement characteristics are specifically explored. An intriguing phenomenon is observed in which the storage modulus of the device samples initially increases to a peak value with a specific load frequency and subsequently decreases as the frequency further increases. This phenomenon cannot be characterized by the conventional Zener model, where the storage modulus monotonically increases with frequency. To better explain this phenomenon, a modified fractional-derivative Zener (FDZ) model is introduced. In this modified FDZ model, the mechanism of frequency-dependent reversible buckling is introduced to explain the increase-decrease trend of storage modulus. Through the comparison between experimental and theoretical results, it is shown that the modified FDZ model effectively captures the increase-decrease trend of the storage modulus in the device samples and exhibits an overall error of less than 8%, which is a substantial improvement over the Zener model.