Optical anisotropy of transparent polymer materials fabricated via 3D printing and their application in photoelasticity

Abstract

Additive manufacturing has been used to fabricate photoelastic models for several years. In the 3D-printing techniques that use photosensitive resins, models are built layer by layer, and the influence of these layers on light propagation and photoelastic fringes is still ambiguous. In this study, a plane polarization arrangement is used to examine the influence of thin layers on light propagation using three disks printed along different directions. The influence of the layers on the light intensity is negligible for the disk where the layer planes are perpendicular to the direction of light propagation. Identical light polarization is observed for the disks where the layer planes are parallel to the direction of light propagation. This is consistent with a polarizer. The evaluation of the thin layers using scanning electron microscopy indicated that the influence of the microstructures on light propagation is the potential cause of these phenomena. The influence of light polarization on photoelastic fringes was presented by comparing the fringes of different disks under circularly polarized light. The results can improve the application of the 3D-printed models in photoelasticity and the understanding of the optical anisotropy of 3D-printed polymer.