where d and L are the diameter and

where d and L are the diameter and length of the wire, and G is the shear modulus of the wire material. Although the torsional stiffness of the wires can be increased by thickening them, wires with large thickness may possibly degrade the horizontal attenuation performance of the suspension system due to the bending elasticity [79]. The bending elasticity of a wire depends on the wire thickness in the first few cm from the suspension points, while the torsional stiffness depends on the thickness integrated over the wire length. Therefore, the wires are designed with large thickness in the middle and small thickness at the ends as illustrated in figure 4.13. The suspension wire is hooked to the suspension bodies by the nail head shapes machined into both ends of the wire.