In solid mechanics, torsion is the twisting of an object due to an applied torque. It is expressed in newton metres (N·m) or foot-pound force (ft·lbf). In sections perpendicular to the torque axis, the resultant shear stress in this section is perpendicular to the radius.

Related formulas


Tapplied torque or moment of torsion (N*m)
JTtorsion constant for the section. It is identical to the second moment of area Jzz for concentric circular tubes or round solid shafts only. For other shapes, J must be determined by other means. (m4)
rdistance between the rotational axis and the farthest point in the section (at the outer surface) (m)
τmaximum shear stress at the outer surface (N/m2)