A visco-plastic device for seismic protection of structures

A new visco-plastic damper (VPD) for seismic protection of structures is introduced in this paper. This device combines and enhances many of the proven characteristics of both displacement-dependent and velocity-dependent devices. The VPD device consists of a block of a high-damping viscoelastic material sandwiched between two steel shapes (plates or channels) bent in a certain configuration to amplify the deformations in the device in order to obtain large tensile and compressive strains in the viscoelastic material. Under low levels of vibrations, the device dissipates energy through amplified axial strains in the viscoelastic material only, however under moderate to strong levels of vibrations, a new source of energy dissipation is added through the yielding of the steel elements. In addition to the energy dissipation, the device provides stiffness through the steel elements as well as the viscoelastic material.