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ME 220 MECHANICS OF MATERIALS LABTorsion LabTest: October 11th, 2007Submitted: October 18th, 2007Matthew OlsenSection 3
SummaryLike the tension test previously, the torsion test is another method of obtaining the stress-strain relationship of a material. However, while the tension test provides the tensile strain and tensile stress, the torsion test provides the shear stress and shear strain directly, which makes this test the preferred method in obtaining said data. Along with the shear data, the modules of resilience and rigidity will also be obtained.To perform this test, a metal rod was fastened to a torsion machine. A troptometer was then used to measure the angle of rotation. Then torsion was applied until the material fractures. The torsion readings as well as the angular deformation were collected and used to calculate the stress, strain, and modules.As expected, the steel performed as a ductile material. The material exhibited elastic behavior up to 2600 in-lbs, giving very little deformation, measuring an angle of 0.069 radians, before yielding took over. At the 2800 in-lb mark, the specimen gave in to plastic deformation, jumping from the 0.069 radians