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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model, as shown in Figure 4(II). The crack initiation and propagation tended to occur at the high-stress concentration areas. These results were compared later with the experimental results.

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Figure 4: (I) Simulation boundary conditions, (II) High- stress concentration by the simulation: (a) model “OR”, (b) model “TK”, (c) model “AD”, (d) model “FS”, and (e) model “AS”.

2.5 Mechanical testing The mechanical tensile tests were done using an Instron load frame with 1000 kN load cell capacity, as shown in Figure 5(I.a). The eye grab hook was fixed by two metal hooks during the experiment, as in Figure 5(I.b). The displacement rate was set to 2 mm/min, and the experimental data recorded were force (F) in Newtons (N) and displacement (D) in mm. The number of each eye grab hook design were two specimens that were tested, and their experimental results were averaged because both specimens of the same model performed in a similar manner. The displacement-controlled monotonic tensile strength tests of the 10 eye grab hooks were performed at ambient temperature.

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Figure 5: (I) The tensile testing machine by Instron (a) and a close-up view of the experimental setup (b). (II) Force-displacement graph for all eye grab hook models. 3. Results and Discussion 3.1 Stress analysis The results were recorded and saved for each eye grab hook. The experimental data of the two eye grab hooks of every model were averaged and plotted on a force-displacement graph. The curves in Figure 5(II) show the behaviour of each eye grab hook model when tested under a displacement-controlled tensile test. The highest strength of all five models was for model “OR”, reaching 2.6 kN. The second highest eye grab hook model was “AS”, with 2.5 kN maximum force. Models “TK” and “FS” behaved similarly (2.0 kN). The weakest of all was model “AD”, with 1.5 kN maximum capacity. The “OR” and “AS” models had the best resistance to failure and sustained more than 5 mm of displacement without failure. The “AD” model failed the earliest, at 3.8 mm.