Design and manufacture of the Torque test setup for small and shapeless materials

Abstract

Torsion test setup FEA First metatarsal Bone PLAIn this study, the design and manufacture of torque test set up has been carried out for small and shapeless speciment. The torque sensor, which has maximum 10 Nm, is used in the test system design. The certain specification of Nema 34 step motor which use to apply torsional force to the specimens is 12 Nm, 24V and 4.2 ampere. The step motor is controlled by the HY-DIV268N-5A Step Motor Driver and the supply voltage of driver is 24 Volts. The information about the degree of the specimen rotation was taken from potantiometer. The information obtained from the sensor and potentiometer was transferred to the LabVIEW software to be representation graphically using the USB 6003 DAQ card. The first metatarsal bone modelled from computerized tomography (CT) images was produced by Ultimaker2 3D printer using polylactic acid (PLA) material. The printed bone model was tested through torsion test set up. At the same time, the 3D bone was prepared for finite element analysis. Boundary conditions were applied in the finite element analysis (FEA) model in accordance with the test setup. The produced bones using 3D printer were subjected to torsion test with the test setup. Also the modelled bone was tested in accordance with the torsion test setup by using finite element analysis. After that, the FEA and experimental test results were compared with each other. As a conclusion, the optimization of the torsional test setup was performed based on the FEA.

Metatarsal bone model production using 3D printing and comparison of material properties with results obtained from CT-based modeling and real bone

“…Since no empirical formulas for metatarsal bones were developed, the coefficients of the femur were used to assign material properties. 31,32 The histogram of the bone models consist of different colors and the red color gives the maximum modulus while blue color gives the minimum modulus X-axis gives the information about density of the bone and the Y-axis represents the Young's modulus corresponding to that density region (Figure 5). Seven right and seven left first metatarsal bones were modeled and material properties (Young's modulus) were assigned according to density using empirical formulas.…”

“…To compare with the torsion test results of the real bone, the produced bone models with different patterns and infill density were subjected to the torsional test. The torsional test was carried out with the designed and produced torsion test set up 31 (Figure 4). The device has two clamps to hold the bones at both ends.…”