PSI - Issue 37

Mohammed Zwawi et al. / Procedia Structural Integrity 37 (2022) 1057–1064 Mohammed Zwawi/ Structural Integrity Procedia 00 (2019) 000 – 000

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effectively. In addition, (Uddanwadiker, 2011) investigated stress patterns in hooks during loading and validated the work with elasticity photographs using diffused light polariscope setups. The author modified the design to decrease failure rates and improve the hook’s working life. Finally, (Rajurkar et al., 2013) analyzed hook stresses via analytical, numerical, and experimental methods. The work also analyzed the stress concentration on hooks with various cross sections using photo-elasticity methods, which enabled differences in the optical properties of an object under mechanical deformation to be observed. All of the aforementioned studies demonstrated the importance of analyzing stresses to determine the safe loading capacity. Due to a lack of research in this area, it is clear that that hook dimensions and cross sections require more intensive research with the assistance of FEM to avoid crack initiation at high-stress concentration points (Singh et al., 2021). In this research, various eye grab hooks with different cross sections made of polylactic acid (PLA) material by fused deposition modeling (FDM) were studied. The hooks were tested using a UTM. The loading experimental results were analyzed to determine the new load capacity for each cross section. Finally, the experimental and FEA results comparison study and failure analysis are presented. 2. Experimental Procedure 2.1 Experimental material The eye grab hooks were made of PLA filament manufactured by eSun®. PLA is a thermoplastic material and is the most common material used in the FDM technique used in additive manufacturing, along with acrylonitrile butadiene styrene (ABS), as a thermoplastic feedstock (Algarni & Ghazali, 2021; Ragan, 2013). The PLA is a biodegradable, hard material and has a low coefficient of thermal expansion. The 3D printer used was a rapid commercial desktop FDM device. The desktop 3D printer was a Creality Ender-3 and is completely open sourced. The PLA filament characteristics are provided by the manufacturer and presented in Table 1. 2.2. Eye grab hook design and printing variables Five different eye grab hooks were designed with different cross sections, as shown in Figure 1. The first eye grab hook model is the original eye grab hook, denoted as “OR”, which is solid with no holes. The model “OR” eye gr ab hook is used as a reference in this research for analysing the change in stresses and strains in the other models with different cross sections. The second eye grab hook model has five horizontal circle holes with a different radius denoted as “TK”. The third eye grab hook model has seven side -to-side horizontal circle holes with different radius and denoted as “AD”. The fourth eye grab hook model has two deep horizontal grooves and denoted as “FS”. The fifth eye grab hook model has three invisible cylindrical holes inside and denoted as “AS”. The mass and volume of “OR” is 50g and 40cm3, “TK” is 36g and 29cm3, “AD” is 36g and 29cm3, “FS” is 40g and 32cm3, and “OR” is 42g and 34cm3. Furthermore, the models were set in Solidworks ® for 3D printing purposes, as shown in Figure 2. The industrial name of the eye grab h ook type is the “shortening eye grab hook” with dimensions as shown i n Figure 3. Table 1: PLA material manufacturer-provided properties. Young's modulus Density Ultimate tensile strength Flexural strength Fracture strain IZOD impact strength 2102 MPa 1.25 g/cm 3 65 MPa 75 MPa 12% 8.5 kJ/m 2