Vridmoment

vridmoment is a term used in Scandinavian languages to denote the twisting effect of a force on a body, commonly translated as torque or twisting moment. It describes the tendency of a force to produce rotation about an axis and is a central concept in rotational mechanics.

Mathematically, vridmoment M is defined as the cross product of the position vector r from the axis to the point of force application and the force vector F: M = r × F. The magnitude is M = r F sin(theta), where theta is the angle between r and F. The SI unit is the newton meter (N·m).

In engineering practice, vridmoment is used to analyze shafts, gears, fasteners, and other rotating components. A positive vridmoment denotes rotation in a specified direction according to a chosen convention; the sign convention varies by discipline.

For a circular shaft under torsion, the torsional shear stress is tau = T r / J, where T is the vridmoment, r the radial distance, and J the polar moment of area. For a solid circular shaft, the maximum shear stress is tau_max = 16 T / (pi d^3).

Measurement of vridmoment is achieved with torque transducers, dynamometers, or strain-gauge based sensors. Related concepts include moment of a force, polar moment of area, and torsion in beams.