Abstract: The dynamic and static feature researches on new and old yaw damper and various installation length of yaw damper are accomplished.It could be concluded that there is no obvious change on static feature,but dynamic feature declines significantly with respect to static after it worked 1.2 million kilometers.Dynamic damping reduces about 10 % and dynamic stiffness descends 15 % probably.Dynamic damping and stiffness reduction rate decreases gradually as amplitude augments and dynamic damping manifests apparently than stiffness.Static feature also shows unconspicuous variation as dynamic damping and stiffness declines with the improving of installation length.Dynamic damping reduces about 2 %~8 % and dynamic stiffness descends 5 %~7 % probably while installation length aggrandizes 40mm.Meanwhile,Maxwell model is not reliable to analyze the its effect on vehicle dynamic performance,it embodies the limit of Maxwell model.

Key words: new damper, old damper, various installation length, dynamic feature, vehicle dynamic performance, Maxwell model