EXPERIMENTAL AND COMPARATIVE ANALYSIS OF COMPRESSIVE BEHAVIOUR AND ENERGY ABSORPTION OF FDM PRINTED PLA AND PETG

Abstract

This paper presents an experimental and comparative analysis of the compressive behaviour and energy absorption of FDM-printed PLA and PETG specimens. A total of five specimens were tested for each material under identical printing and loading conditions. The mechanical response was evaluated based on stress–displacement curves obtained from compression testing.

The results indicate that PLA exhibits higher peak stress values, reflecting greater stiffness and load-bearing capacity, but also shows more pronounced variability and less stable post-peak behaviour. In contrast, PETG demonstrates lower peak stress but more gradual and stable deformation, indicating higher ductility and improved energy dissipation. Energy absorption was determined by calculating the area under the force–displacement curves using numerical integration based on the trapezoidal rule. The results show that PLA can achieve higher energy absorption under specific conditions, but with significant variability, whereas PETG provides more consistent and predictable performance. For clarity of comparison, representative specimens were selected and presented in detail, while the full experimental dataset was used for overall analysis. The findings highlight the influence of material type and internal structure on compressive behaviour and provide useful insight for material selection in FDM applications.