Numerical analysis of U-shaped hysterisis steel damper with energy absorber for seismic areas

Abstract

This paper investigates one type of metallic dampers used in many large buildings in seismic areas. The previous studies have shown a possibility of the introduced damper to act as a damper as well as energy absorber through yielding on some parts of the damper. However, the occurred yielding caused a plastic deformation after unloading. The study aims to substitute the previous critical area to another part which is considerably uncritical during loading. Therefore, an additional part in the form of a slender column is inserted into the damper. The bottom part of the column is clamped to the base plate of the damper. There is a restoring moment acting on the column which was able to restore a large displacement of the damper to at least a small residual plastic displacement after unloading. A stiffness, strength and energy dissipation of the modified damper is determined by a nonlinear finite element technique which involves both geometrically and materially nonlinearities. The model was subjected by a monotonic increasing load which is applied horizontally through the method of displacement control until one cycle of hysteresis is formed. The final result is in a term of comparison of hysteresis curves between a full model of hysteresis damper with and without a slender column.