Predicting Critical Loads in U-Notched 3D-Printed Acrylonitrile-Styrene-Acrylate and Carbon Fiber-Reinforced Acrylonitrile-Styrene-Acrylate Specimens Using Failure Assessment Diagrams

Abstract The mechanical behavior of three dimensional (3D)-printed polymeric materials, particularly those obtained through fused filament fabrication (FFF), has been extensively investigated over the last few years with the aim of scaling the use of these materials from prototyping purposes to structural applications. In this regard, acrylonitrile-styrene-acrylate (ASA) terpolymer emerges as a promising option, given that this polymer displays outstanding resistance to weathering agents, together with reasonable mechanical properties, both dimensional and thermal stability, and relatively good resistance to environmental stress cracking, among other properties. One of the necessary requirements when studying the structural use of a given material is to have tools for evaluating its structural integrity in the presence of defects. Thus, this paper provides an analysis of fracture loads in 3D printed (FFF) single edge notched bending (SENB) specimens containing U-notches and made of pure ASA and carbon fiber reinforced (10 wt. %) ASA. The specimens cover three different raster orientations (0/90, 45/−45 and 30/−60) and contain four different notch radii (from 0 mm up to 2 mm). The fracture loads were predicted using the failure assessment diagram (FAD) methodology in conjunction with the theory of critical distances (TCD). The results show how this FAD-TCD approach is capable of providing safe, accurate predictions of fracture loads for this type of material when containing notch-type defects. The safety of the predictions relies directly on the criterion (in terms of probability of failure) assumed to define the mechanical properties included in the FAD approach.