PSI - Issue 77

Pawel Madejski et al. / Procedia Structural Integrity 77 (2026) 323–330 Author name / Structural Integrity Procedia 00 (2026) 000–000

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4. Conclusions This study demonstrates that the infill geometry has a significant impact on the tensile performance of 3D printed PLA. The Octet lattice achieved the highest strength (30.43 MPa) and notable ductility due to its stretch dominated design. The Lines pattern excels in elongation and energy absorption, making it suitable for applications requiring toughness. Cubic and Triangles infills offered higher stiffness but lower ductility, while Quarter-Cubic provided balanced, variable properties. Triangle patterns, with higher thermal conductivity, traded tensile strength for stiffness—ideal for heat-dissipating applications, such as electronic enclosures. Quarter-Cubic and Lines delivered better ductility and impact resistance, fitting insulation-focused designs. Octet offered a unique mix of strength and moderate thermal performance for multifunctional uses. Thermal-stress analysis of Cubic infill showed stable temperatures in the elastic range, rising just before peak stress—marking the onset of plasticity and failure. A sharp temperature drop followed the fracture, linking heat generation to mechanical damage. This correlation highlights thermal monitoring as a tool for real-time health assessment in printed parts. Overall, targeted mechanical and thermal properties in PLA can be achieved via strategic infill selection, enabling optimized designs for thermomechanical housings and energy devices. Acknowledgements The research project is supported by the program “Excellence Initiative – Research University” for AGH University. References [1] S. Farah, D. G. Anderson, and R. Langer, “Physical and mechanical properties of PLA, and their functions in widespread applications — A comprehensive review,” Adv Drug Deliv Rev, vol. 107, pp. 367–392, Dec. 2016, doi: 10.1016/J.ADDR.2016.06.012. [2] D. Garlotta, “A Literature Review of Poly(Lactic Acid),” J Polym Environ, vol. 9, no. 2, 2001. [3] B. PW, “Studies in large plastic flow and fracture. ,” Mc Grraw Hill, New York., 1952. [4] W. D. , & R. D. G. (2020) Callister Jr, “Materials science and engineering: an introduction. ,” John wiley & sons, 2020. [5] A. Lanzotti, M. Grasso, G. Staiano, and M. Martorelli, “The impact of process parameters on mechanical properties of parts fabricated in PLA with an open-source 3-D printer,” Rapid Prototyp J, vol. 21, no. 5, pp. 604–617, Aug. 2015, doi: 10.1108/RPJ-09-2014-0135/FULL/XML. [6] B. Wittbrodt and J. M. Pearce, “The effects of PLA color on material properties of 3-D printed components,” Addit Manuf, vol. 8, pp. 110– 116, Oct. 2015, doi: 10.1016/J.ADDMA.2015.09.006. [7] L. Suryanegara, A. N. Nakagaito, and H. Yano, “The effect of crystallization of PLA on the thermal and mechanical properties of microfibrillated cellulose-reinforced PLA composites,” Compos Sci Technol, vol. 69, no. 7–8, pp. 1187–1192, Jun. 2009, doi: 10.1016/J.COMPSCITECH.2009.02.022. [8] M. Kowalczyk, E. Piorkowska, P. Kulpinski, and M. Pracella, “Mechanical and thermal properties of PLA composites with cellulose nanofibers and standard size fibers,” Compos Part A Appl Sci Manuf, vol. 42, no. 10, pp. 1509–1514, Oct. 2011, doi: 10.1016/J.COMPOSITESA.2011.07.003. [9] A. A. Marek and V. Verney, “Photochemical reactivity of PLA at the vicinity of glass transition temperature. The photo-rheology method,” Eur Polym J, vol. 81, pp. 239–246, Aug. 2016, doi: 10.1016/J.EURPOLYMJ.2016.06.016. [10] C. C. Chen, J. Y. Chueh, H. Tseng, H. M. Huang, and S. Y. Lee, “Preparation and characterization of biodegradable PLA polymeric blends,” Biomaterials, vol. 24, no. 7, pp. 1167–1173, Mar. 2003, doi: 10.1016/S0142-9612(02)00466-0. [11] Muna, I. I., Mieloszyk, M., & Rimasauskiene, R. (2024). Characterization of the thermal and mechanical properties of additively manufactured carbon fiber reinforced polymer exposed to above-zero and sub-zero temperatures. Journal of Materials Research and Technology, 33, 9832 9842. [12] Muna, I. I., & Mieloszyk, M. (2024). Numerical modeling of thermal effects on the mechanical behavior of additive manufactured continuous carbon fiber reinforced polymer: from microscale to macroscale. Procedia Structural Integrity, 54, 437-445. [13] Maqsood, N., Mahato, S., Rimašauskas, M., & Muna, I. I. (2023). Experimental analysis, analytical approach and numerical simulation to estimate the elastic modulus of 3D printed CCFRPC under mechanical loadings. Journal of the Brazilian Society of Mechanical Sciences and Engineering, 45(9), 456.