Explain why the torsion test can be considered to provide a better assessment of plasticity than the tensile test.

Answer and Explanation:

The main objective that the torsion test serves is the determination of the material behavior or the behavior of the test sample when subjected to torsional stresses or forces due to the application of moments that results in shear stress along the axis.

Plasticity is the property of elastic material and tension or shear stresses leads to plasticity in a material where these links are the weakest, that gives torsion test a major advantage over the tension test.

Torsion tests are performed on materials to deduct properties like the shear modulus of elasticity, the torsional strength, and the MOR, i. e., Modulus of Rupture.

This test can be used to obtain larger strain values of strain without any complexity as that in tension test.

This test provides a curve of shear-stress-shear strain which is more significant in determining the plasticity as compared to the curve of stress-strain in tension test.

Maximum torque for a given value of maximum stress will be 2 times higher in torsion as that of tension.

In torsion, for plastic flow, the threshold value of shear stress is achieved before the threshold value of normal stress for fracture whereas in tension the critical value of normal stress is achieved sooner than the critical shear for plastic flow.