Effect of Different Standard Geometry Shapes on the Tensile Properties of 3D-Printed Polymer

The objective of this research is to conduct a comparative analysis between rectangular-shaped ASTM D3039 specimens with different angles (0°, 15°, and 90°) and various tensile test specimens based on ASTM and ISO standards, all 3D-printed using polyethylene terephthalate glycol (PETG) material through FDM. The study aimed to assesses the weak spot commonly found at the neck of the specimens. Two different printing orientations, namely flat and on-edge, were investigated, and a comprehensive examination and comparison were made regarding the variations in tensile strength, E-modulus, strain, and elongation at break among the tested samples. Additionally, the broken areas was evaluated, and a numerical study utilizing the finite element method (FEM) was conducted to identify stress risers' locations in each specimen type. The experimental results demonstrated that the ASTM D3039-0° specimen exhibited the best tensile properties when printed in the on-edge orientation, while the flat orientation yielded the best results in terms of the broken area. On the other hand, the ISO 527-2 specimens displayed the lowest tensile properties, regardless of the printing orientation. The study highlighted the enhanced tensile properties achieved with the rectangular shape. Specifically, the tensile strength of ASTM D3039-0° was 17.87% and 21% higher than that of the ISO 527 geometry shape for the flat and on-edge orientations, respectively. The numerical analysis indicated that the ISO 527-2 specimen had either no or minimal stress raisers, and the higher stresses observed in the narrow section were isolated from the gripping location.