Critical strain energy release rate in additively manufactured polymers through comparative study of ABS and PLA across various raster angles

Abstract

To effectively integrate 3D-printed components into real-world applications, it is crucial for designers to fully understand the behavior of these constructions, particularly their fracture characteristics. This study addresses the fracture behavior of Fused Deposition Modeling (FDM) 3D-printed Double Cantilever Beam (DCB) specimens by analyzing the Mode-I strain energy release rate. The investigation encompasses two materials: (Acrylonitrile Butadiene Styrene) ABS, a brittle reference, and Polylactic acid (PLA), a ductile reference. Finite Element Analysis (FEA) is utilized to predict fracture behavior and evaluate the applicability of the model across various unidirectional raster angles (0°, 30°, 45°, 60°, and 90°) based on the Cohesive Zone Model (CZM). The study systematically explores fracture initiation, crack propagation, and critical failure points. Scanning Electron Microscopy (SEM) fractography examines the effects of different raster angles and material properties on construction behavior. The results reveal that the 60-degree raster angle yields the highest critical energy release rate, attributed to the mixed Mode-I/II interaction and significant shear deformation, with 2.3 mJ/mm² values for ABS and 2.4 mJ/mm2 for PLA. This angle also demonstrates strand bridging, enhancing the material’s toughness. Conversely, samples with a 45-degree raster angle exhibit lower critical energy release rates, indicating reduced fracture resistance under these conditions. This comprehensive analysis provides valuable insights into optimizing 3D-printed structures for improved performance in practical applications.