VIBRATION DAMPER

PROBLEM TO BE SOLVED: To provide a vibration damper which eliminates the need of an excessive vibration energy at the start of plastic deformation even if forces of compression and tension are applied thereto by an earthquake or the like and which can sufficiently exhibit energy absorbing performance by the plastic deformation. SOLUTION: This vibration damper 1 is installed, as a brace, for example, between a base D, a beam H, and columns P1, P2 as the structural members of a building so as to absorb vibration energy generated by an earthquake or the like. The vibration damper includes a considerably long shaft member 2 extending in the axial direction and an plastically deformable tube 6 of circular shape in cross section which is fixed to one end (bottom end) of the shaft member 2 in the axial direction of the shaft member 2. The plastically deformable tube 6 includes a compressively deformable and tensely deformable plastically deformable part 7 at the axial intermediate part over the entire circumference. The deformation of the plastically deformable part 7 changes the axial dimension of the plastically deformable tube 6. COPYRIGHT: (C)2011,JPO&INPIT