Thermal Aging and Geometry-Driven Changes in Strength of 3D-Printed Polymers

The benefits of additive manufacturing (AM, i.e., 3D printing) have made it one of the most widely used and favored production techniques across a variety of industries. In the current study, the influence of geometry and thermal aging on the mechanical strength of AMed parts has been investigated. In this context, specimens based on fused deposition modeling were printed using polylactic acid material. The specimens with three distinct geometries were created and analyzed since the geometry of AMed parts affects their mechanical performance. In this study, tensile tests were conducted under static loading circumstances, specifically on dumbbell-shaped, smooth, and V-notched test coupons. Furthermore, we conducted accelerated thermal aging between −5 °C and 35 °C, which is below the glass temperature of the material under investigation, to assess the impact of the thermal environment. In addition, a series of finite element models were developed to study the stress distribution and deformation in the examined components. According to the results, for unaged specimens, smooth samples demonstrated the highest fracture load at 1980.5 N, while dumbbell-shaped samples recorded the lowest at 1173.9 N. Moreover, the V-notched specimens sustained higher fracture loads compared to dumbbell-shaped samples across both aged and unaged conditions. This study’s findings demonstrate that in designing 3D-printed parts, consideration must be given to their geometric appearance and environmental operating circumstances.