Mechanical Performance of 3D Printed Polylactic Acid/MWCNT Brackets: Effects of CNT Concentration and Printing Orientation on Stress-Strain Behavior and Deflection Characteristics

The present research study explores the mechanical properties of poly lactic acid (PLA) composites reinforced with multi-walled carbon nanotubes (MWCNTs), focusing on their performance in triangular, inclined, and curved support bracket geometries. Tensile tests revealed that tensile stress increases with MWCNT concentrations up to 3 wt.%, but decreases at 5 wt.%. Enhanced mechanical performance at lower concentrations is attributed to uniform CNT dispersion within the PLA matrix, facilitating effective load transfer. Conversely, at 5 wt.%, MWCNT agglomeration disrupts matrix continuity, leading to weaker mechanical properties. The alignment of CNTs with the loading direction significantly influences the performance, with 0° printing angles yielding higher tensile strength due to optimized load transfer. The geometric configuration of the brackets further affects deflection behavior; maximum deflections were observed to decrease with increasing MWCNT content, particularly at 3 wt.%, but slightly increase at 5 wt.%, indicative of reduced stiffness due to aggregation. This work emphasizes the importance of both CNT concentration and geometric design in optimizing the mechanical characteristics of PLA/MWCNT composites; that revealing how to vary geometries impact stress distribution on overall performances.