Material Characterization and Fracture Prediction of FDM Printed Parts

Abstract

In order to take advantage of the design freedom that Additive Manufacturing offers, most applications require reliable material characterization. This can ensure that a design performs within its environment and life requirements. This work discusses two models. One investigates the raster angle dependency of stiffness properties and the other numerically predicts fracture in Fused Deposition Modeling (FDM) printed polymer parts. Pre-processing of FDM geometry was done in Abaqus CAE (SIMULIA TM). FEA and post-processing was done in BSAM, which is a damage prediction software developed for composites. BSAM uses a regularized extended finite element approach of Discrete Damage Modeling. In BSAM, boundary conditions, connectivity and material properties have been specified. A similar trend in the stiffness properties was observed when the predicted modulus values were compared to experimental test data. FDM printed DCB specimens were tested and the Mode I fracture toughness values (GIC) were obtained. A set of experiments was performed to study the effect of time and temperature on the Mode I fracture toughness (GIC) of ABS. The GIC values can be used to develop the fracture model in BSAM. Tensile tests were performed on ABS specimens to calculate the Elastic modulus. The experimental modulus values were compared to the values obtained from the model for validation. This model provides a basis for strength and fracture prediction of FDM printed parts.