Several reports have been published on the FEM analysis for coil springs. All of them, however, based on the beam theory, so that it is difficult to get the stress distribution in the cross section. So, we have been obliged to use, for example, the Wahl’s stress correction factor. To get over this difficulty, we developed the isoparametric element analysis for curved and twisted beams. In this report, we introduce such method and some examples. We think that it is
useful to analyze not only coil springs, but also wire springs and stabilizer bars.