The impacts of infill patterns and densities on the mechanical characteristics of items created by material extrusion additive manufacturing systems were investigated in this study. It is crucial to comprehend how these variables impact a printed object’s mechanical characteristics. This work examined two infill patterns and four densities of 3D-printed polyethylene terephthalate reinforced with carbon-fiber specimens for their tensile characteristics. Rectilinear and honeycomb infill designs were compared at 100%, while each had the following three infill densities: 20%, 50%, and 75%. As predicted, the findings revealed that as the infill densities increased, all analyzed infill patterns’ tensile strengths and Young’s moduli also increased. The design with a 75% honeycomb and 100% infill density has the highest Young’s modulus and tensile strength. The honeycomb was the ideal infill pattern, with 75% and 100% densities, providing significant strength and stiffness.

In the quest for high-performance materials capable of withstanding extreme environments, Additive Manufacturing (AM) has emerged as a powerful tool for designing customized polymer composites. By integrating functional nanofillers into thermoplastic matrices, it becomes possible to enhance mechanical, thermal, and structural properties while exploiting the freedom of AM. This study introduces a novel class of additively manufactured composite materials that combine ceramic nanofillers (Aerosil 300) with a polycarbonate (PC) matrix. Aerosil was incorporated at weight fractions of 1%, 2%, and 4% to improve the mechanical performance of the polymer. The main objective is to investigate the mechanical behavior of these composites under extreme thermal conditions, through static compression tests performed at temperatures ranging from − 90 °C to 80 °C. The influence of Aerosil content on void formation and interlayer quality is further examined through SEM analysis, with the aim of minimizing process-induced defects. Two loading configurations were tested: out-of-plane (compression parallel to the printing direction) and in-plane (compression perpendicular to the printing direction), to assess the influence of printing orientation on the mechanical response. In addition to the experimental approach, a comprehensive numerical analysis was carried out using Digimat and Abaqus to simulate both the mechanical behavior and the additive manufacturing process. A 3D thermomechanical model was developed to evaluate the impact of printing parameters on residual stresses, temperature gradients, deflections, and warpage in Aerosil/PC printed parts. The results demonstrate that the addition of Aerosil 300 significantly enhances the mechanical and thermal performance of the composites under harsh conditions. Furthermore, the combined numerical-experimental approach proves effective in predicting process-induced defects and provides valuable insights for optimizing additive manufacturing processes.

In this paper, we will be interested in bending tests on a polymer matrix reinforced with graphene nanofillers. The mechanical behaviour and the damage kinetics were determined. The samples were made using controlled dispersions of graphene nanosheets (GNP) in EPON 862 matrix. Various samples with different contents of GNP were made (0, 0.5, 1, 2.5, 5 and 10% by weight). Mechanical properties such as maximum stress, strain at break and Youngs modulus were determined. After each test, the fracture surfaces were characterised using optical microscopy (OP) and scanning electron microscopy (SEM). Experimental results show that the fracture toughness of the GNP/epoxy-based nanocomposites decreases with an increasing percentage of nanofillers. The flexural strength of the samples with 10wt% of graphene significantly decreased compared to neat epoxy. Based on stress-strain data and the fracture surface analysis, graphene nanosheets seem to impact the mechanical behaviour and the kinetics of the damage. The influences of the weight percentage of GNP on the EPON matrix properties and the performance of the nanocomposites are discussed. In addition, the evolution of bending performance and damage kinetics with graphene content was obtained and analysed.