Torsjonell

Torsjonell is an adjective used in several Scandinavian languages to denote concepts related to torsion, the twisting of an object around its longitudinal axis. In English, the corresponding term is torsional. The word is commonly found in physics, engineering, and materials science to describe properties, responses, and analyses involving twisting under torque.

In mechanical engineering, torsion describes how shafts and other circular cross-section members react to applied torque. The torque T induces a twist along the length, with the rate of twist given by dθ/dx = T/(G J), where G is the shear modulus and J is the polar moment of area. The total angle of twist over a length L is θ = T L/(G J). The maximum shear stress in a solid circular shaft is τ_max = T r / J, where r is the outer radius. The torsional stiffness is k_T = G J / L, relating torque and angle by T = k_T θ. The energy stored in torsion is U = (1/2) T θ = (1/2) (G J / L) θ^2.

Applications of torsion include drive shafts, torsion springs, and components subjected to twisting loads. Designers consider torsional fatigue, vibration, and resonance, as well as torsional stiffness and the distribution of shear stress. Torsion tests on materials quantify shear properties and validate design models.

Etymology and usage: the term derives from Latin torsio, through French torsion, into Scandinavian languages, where torsjonell or its cognates are used to describe torsional phenomena. See also torsion, torque, shear modulus, polar moment of area, torsional vibration.