A universal relationship between spring constant and torsion constant

A universal relationship exists between the torsion constant of a wire and the spring constant of a close-coiled helical spring wound from the same wire. The relationship, which is verified experimentally, involves only the coil radius of the wound spring and is independent of the wire diameter, length, and material. In addition to having a practical application in designing helical springs, this relationship leads to a dynamical equivalence between the class of mass-spring systems and the class of torsion pendula. (C) 2001 Elsevier Science Ltd. All rights reserved.