A damper is a device that provides resistance to motion and reduces energy consumption during movement. The use of damping to absorb energy and reduce vibration is not a new technology. Various dampers (or shock absorbers) have already been applied in industries such as aerospace, aviation, military, firearms, and automobiles to reduce vibration and energy. Since the 1970s, people have gradually applied these technologies to structural engineering such as buildings, bridges, and railways, and their development has been very rapid. Especially for hydraulic viscous dampers with a history of more than 50 years, before they were accepted by the structural engineering community in the United States, they underwent a long process of extensive experimentation, rigorous review, repeated verification, and especially earthquake testing.