Characterization of shear/tensile mechanical properties of three-dimensional-printed polylactic acid specimens based on orthogonal raster

With the wide application of three dimensional (3D)-printed products, related studies on 3D-printed materials with interleaved raster and subjected to complex stress states should receive sufficient attention. In this study, 3D-printed tensile specimens and two types of shear–tensile specimens with different printed angles were prepared by changing the distribution of internal orthogonal raster orientation. Uniaxial tensile and shear–tensile tests combined with digital image correlation revealed that the ultimate strength and strain of tensile specimens depended on the printing angle, also showed that the maximum values of strength and strain were obtained with the printing angle of 0°/90°. At different printing and slot angles, ultimate strength slightly differed, whereas ultimate strain remarkably differed, between the two kinds of shear–tensile specimens. Subsequently, the corresponding failure mechanism, such as internal raster necking, delamination, and deflection, dependent on printing and slot angles were analyzed by combining the fracture morphologies of the tensile and shear–tensile specimens.