Computer · Strength of Materials

Assertion (A): Circular tubes are more efficient than solid bars in resisting torsional loads. In a hollow tube, most of the material is near the outer boundary where both shear stresses and moment arms are highest. Hence, for weight reduction, it is advisable to use circular tubes. Reason (R): The shear stresses in a solid circular bar are maximum at the outer boundary of the cross-section and zero at the center. Therefore, most of the material in a solid shaft is stressed significantly below the maximum shear str ess.