Analisis Kekuatan Struktur Bodi Magnetik Separator Portabel Berbahan PETG

Abstract

A portable magnetic separator requires a body structure capable of sustaining operational loads without excessive stress or deformation. This study aimed to evaluate the effect of body thickness variation made of Polyethylene Terephthalate Glycol (PETG) on von Mises stress, displacement, and safety factor, as well as to determine the most appropriate thickness based on structural strength and material efficiency. The analysis was conducted using the finite element method through the Stress Analysis feature in Autodesk Inventor. Three body thicknesses were evaluated, namely 2 mm, 3 mm, and 4 mm. The applied loading conditions consisted of a sand load of 19.62 N, a motor and magnet load of 14.72 N, the self-weight of the body through gravity loading, and an equivalent radial force of 7.98 N generated by the rotation of the magnetic system. The radial force was calculated using a rotating mass of 0.7 kg, a rotational radius of 0.026 m, and a rotational speed of 200 rpm. It was then represented as a conservative static load acting perpendicular to the rotational axis. A mesh size of 0.0144 was used based on the previous mesh convergence test, which satisfied the relative error criterion of less than 5%. The simulation results showed that the 2 mm body produced a maximum von Mises stress of 1.49524 MPa and a maximum displacement of 0.165241 mm. The 3 mm body generated a maximum von Mises stress of 1.47640 MPa and a maximum displacement of 0.149633 mm. Meanwhile, the 4 mm body produced a maximum von Mises stress of 1.46351 MPa and a maximum displacement of 0.139497 mm. All stress values were substantially lower than the PETG yield strength of 50 MPa, while the resulting displacements remained below the functional design limit of 1 mm. Autodesk Inventor displayed a minimum safety factor of 15 for all thickness variations, whereas the theoretical calculations resulted in safety factors of 33.44, 33.87, and 34.16 for the 2 mm, 3 mm, and 4 mm bodies, respectively. Increasing the body thickness reduced both stress and displacement; however, the differences in structural response among the three variations were relatively small. Therefore, the 2 mm thickness was selected as the most efficient design because it met the structural safety requirements while maintaining a lower body mass and material consumption.