Numerical and Experimental Fracture Analysis of 3d-Printed ABS Components

Resumo

Additive manufacturing (AM), also known as three-dimensional (3D) printing, offers several advantages over traditional manufacturing approaches, including design flexibility, extensive customization capabilities, waste reduction, and the ability to produce complex structures quickly. Polymers are recognized as key raw materials in 3D printing, and among the various 3D printing technologies, the fused filament fabrication (FFF) has been gaining  prominence for polymer-based printing. In this technique, a great number of parameters controls the printing process and directly impact the final behavior of the produced part. Over the years, most research has focused on printing parameters related to the ultimate strength of printed specimens. However, both the maximum load-bearing capacity and fracture toughness are critical material parameters for the safe and efficient design of components subjected to mechanical loading. The characterization of crack propagation in additively manufactured components is inherently complex, primarily due to substantial microstructural heterogeneities arising from the wide range of customizable printing parameters, which, in turn, significantly influence the crack growth rate. The extended finite element method (XFEM) has gained significant attention in the numerical simulation of crack propagation and is being increasingly adopted in engineering applications. Among its many advantages, notable features include the capability to model discontinuities independently of the element interface conditions and the elimination of the need for mesh redefinition as the crack propagates. In this context, the objective of this research is to apply the XFEM method in conjunction with cohesive zone models (CZM) for the characterization of crack propagation in acrylonitrile butadiene styrene (ABS) components produced through additive manufacturing processes. For this purpose, this study examines the influence of the cubic infill pattern, raster angles, and build orientations on mode I fracture behavior in ABS specimens produced via FFF. Experimental three-point bending tests were performed and used to calibrate numerical model based on the Extended Finite Element Method (XFEM) coupled with Cohesive Zone Models (CZM) in Abaqus. The results demonstrate XFEM's effectiveness in capturing crack propagation in FFF parts and highlight the significant impact of process parameters on fracture performance.