Impact of strain rate on mechanical properties of polylatic acid fabricated by fusion deposition modeling

Abstract

AbstractThe primary objective of this research is to investigate the impact of strain rate on the mechanical properties of polylactic acid (PLA) fabricated through fused deposition modeling. PLA material was fabricated in a grid pattern with 75% infill density, a 0.16 mm layer height, and a ± 45° printing direction. This study specifically investigated tensile strength, flexural strength, and interlaminar strength with respect to varying crosshead speeds (1, 2, 3, 4, and 5 mm/min). The highest tensile strength noted was 40.13 MPa at a cross—head speed of 5 mm/min. Maximum elongation of 7.1% was noted on cross head velocity of 1 mm/min, and the maximum interlaminar strength reached 76.04 MPa at 4 mm/min. At a crosshead speed of 4 mm/min, the tensile strength measured was 38.36 MPa, which is a value close to the maximum result achieved in the tensile test. Interlaminar strength was notably higher at a crosshead speed of 4 mm/min, indicating a strong integrity of the printed layers. The values for elongation percentage and flexural strength were also moderate at a crosshead speed of 4 mm/min, which was 4.9% and 55 MPa, respectively. Therefore, crosshead speed of 4 mm/min appears to be an optimum factor for testing 3D printed PLA parts. This research sheds light on understanding the critical influence of strain rate in the mechanical performance of 3D printed PLA.