engleski

Evaluation of photoelastic methods for stress analysis on additively manufactured models

Photoelasticity has comprehensive engineering applications in the study of fracture mechanics, stress concentration and contact mechanics, usually associated with the verification and validation of numerical methods and models [1]. A review of the research published in the field of photoelastic investigations on models produced by additive manufacturing (AM), has shown that further research on digital light processing (DLP) printed parts is justified. In DLP an entire layer of material is cured at once using an image projected by a DLP device, however the images are pixelated, creating an anisotropy that can be reduced, or even removed in transparent resins by the post-curing process that has the biggest influence on material behavior [2]. Therefore, to explore the influence of the build orientation and the level of post-curing on material behavior, a two-dimensional digital photoelasticity technique was used with pure bending tests performed on rectangular beam samples manufactured from commercial DentaCLEAR photoreactive resin by means of a special loading device, a Tiedemann circular polariscope, and a high-resolution digital camera. The resulting experimental data is then used for the calibration of finite element method (FEM) based models, where the isotropic material models are used for fully cured samples, and orthotropic models for uncured and partially cured ones. In order to validate the calibrated FEM models, arbitrarily oriented test samples were manufactured and tested under the same loading conditions.

Photoelasticity, Additive Manufacturing, Digital Light Processing (DLP), FEM

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