Investigating the effect of printing speed and mode mixity on the fracture behavior of FDM-ABS specimens

Abstract

The majority of engineering components are subjected to a multiaxial state of stress. This multiaxiality can be induced by a complex loading or complex geometry of the part. Therefore, investigating the mixed-mode fracture behavior would be an essential task to have an assessment of the fracture resistance in the mechanical components. Additive Manufacturing (AM) as one of the latest fabrication techniques has shown great benefits for design and fabrication of complex components. Among AM techniques, Fused Deposition Modelling (FDM) is one of the favorite processes that is currently used not only for prototyping but also for fabrication of complex structural components. Therefore, this research aims to evaluate mixed mode I/II fracture behavior of the FDM Acrylonitrile Butadiene Styrene (ABS) specimens with special focus on the effects of printing speed and mode mixity on fracture resistance. Four different printing speeds of 30, 50, 70, and 90 mm/s were used for fabricating the test specimens. Aside from these speeds, four different crack angles of 0, 15, 30, and 40° were used to investigate mixed-mode fracture behavior using Semi-Circular Bending (SCB) specimens. The fracture loads of the tested specimens were then predicted by employing the Equivalent Material Concept (EMC) method combined with the J-integral approach and the accuracy of the predictions were studied for various cases. Ultimately, Scanning Electron Microscopy (SEM) was used to investigate the failure mechanisms in fractured SCB specimens and link the fracture features to the fracture resistance of the FDM specimens.