A helical steel spring seems to be a very regular structure. But the following calculation shows that this is not valid for all points of view. Here a steel spring with three complete coils is considered. The lower end of the spring is fixed for all translations and the rotations around all three principal spatial axes. The upper end the spring is free in all degrees of freedom. This example is functional, only with the Structural Mechanics product from the MapleConnect series.
Harald Kammerer