PSI - Issue 55

America Califano et al. / Procedia Structural Integrity 55 (2024) 201–205 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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although in recent years this trend is changing. First construction projects have been implemented by using AM processes, especially based on the use of large-manufactured products technologies (Gardner (2023), Paolini et al. (2019)). These developments can be attributed to the distinctive features that AM offers, mainly related to geometrical complexity freedom, wide range of material that can be used and the automation of the process. Interesting advancements in this field include the use of Fused Filament Fabrication (FFF) technology for the production of plastic parts. The possibility to easily produce parts that are structurally strong, UV-resistant and recyclable would ensure not only the design of futuristic forms but also processes that are sustainable in every aspect (Gopal et al. (2023)). Among the wide range of plastic materials, particularly interesting for construction engineering applications appear to be PolyMethylMethAcrylate (PMMA) and PolyCarbonate (PC). PMMA is a transparent polymer with excellent weathering and UV resistance. Its transparency and ability to be easily fabricated make it perfect for windows, lights, and transparent panels. On the other hand, PC is known for its outstanding resistance to impact and breakage. It is a lightweight material, tinted or transparent, that can be used for partition walls, roofing, or skylights. The performances of AMed parts are highly dependent on the setting of numerous process parameters. Thus, knowledge of their influence on mechanical properties and geometric stability is crucial to produce satisfactory AM parts (Alfieri et al. (2022), Sepe et al. (2022)). The literature reports research that involved the study of the mechanical properties of Additively Manufactured (AMed) PMMA and PC by considering different technologies. Petersmann et al. (2023) investigated the effect of some post-treatments on the mechanical properties of PMMA-based materials produced by FFF. In (Petersmann et al. (2020)), PMMA mechanical properties for dental implant applications were investigated, finding that they hardly depend on the temperature changes inside the human body. The literature is more substantial concerning the study of the performance of AMed PC. In (Cole et al. (2020)) the physical properties, including tensile ones, of AM PC were studied, observing that tensile properties degraded in presence of pore networks and poor interfacial bonding. Furthermore, Reich et al. (2019) studied the tensile properties of recycled PC produced by material extrusion. They achieved interesting results demonstrating that recycled PC can be 3D printed and guarantees high-strength and heat-resistant products at low cost. This study reports an experimental investigation about the effect of raster angle variations on both tensile and flexural properties of transparent PMMA and white PC samples. The results showed high repeatability of the process and satisfactory performances achieved for both materials, in some cases even comparable with those shown by their moulded versions. This document marks represents an advancement in the existing literature by contributing to a more comprehensive understanding of the mechanical behavior of these two materials with a glimpse to their use in the field of construction engineering. 2. Materials and Methods Specimens made of PMMA and PC were obtained through the FFF technology, particularly by means of a Ultimaker s5 Pro Printer. The related setting of printing parameters is listed in Table 1 for both materials. Both dog bone and rectangular specimens were printed according to ASTM E8 and ASTM D790 Standards respectively. The dimensions of specimens are reported in Figure 1. Five printing cycles were carried out for each considered material; each cycle led to the printing of six specimens (Figure 2a): three dog-bone ones (with printing patterns: 0°, ± 45°, and 90°) and three rectangular ones (with printing patterns: 0°, ± 45°, and 90°) (Figure 2b). Therefore, a total of 30 specimens for each material was printed.

Table 1. FFF printing parameters.

PMMA 250°C 110°C 0.1 mm

PC

Nozzle temperature Bed temperature

260°c 110°C 0.1 mm

Layer height Wall number

1

1