Much more buildings with seismic dampers are designed and constructed after The Hyougoken-Nanbu earthquake. Some basic tests of RD series were issued preceding in previous paper. Concerning more heavy clamping RD-tube and long stroke RD-tube tests are made a report. RD series have non linear damping force. This is prospect of non-Newton viscous theory. Reduced damping coefficient is modeling from nonlinear damping force to linear damping, equivalent of input energy. Reduced damping coefficient model is extremely similar to nonlinear damping model in earthquake response analysis.

Some basic issues associated with development of seismic dampers (Rotary Damping series) applied to ball screw for seismic performance enhancement are studies in this paper. RD series are consists of ball screw section and damper section. RD series has 2 types of damper section, RD-tube has a tube type of damper section, RD-disk has a disk type of damper section. RD series have more efficient viscous damping force applied to amplification of ball screw.