Ricerc@Sapienza

Viscous fluid damping has been used worldwide to provide energy dissipation to structures during earthquakes. Semi-active dissipation devices have also shown significant potential to re-shape structural hysteresis behaviour and thus provide significant response and damage reduction. However, semi-active devices are far more complex and costly than passive devices, and thus potentially less robust over time. Ideally, a passive device design would provide the unique response behaviour of a semi-active device, but in a far more robust and low-cost device. This study presents the design, development and characterization of a passive Direction and Displacement Dependent viscous damping (D3) device. It can provide viscous damping in any single quadrant of the force-displacement hysteresis loop and any two in combination. Previously, this behaviour could only be obtained with a semi-active device. The D3 device is developed from a typical viscous damper, which is tested to evaluate the baseline of orifice sizing, force levels and velocity dependence. This prototype viscous damper is then modified in clear steps to produce a device with the desired single quadrant hysteresis loop. The overall results provide the design approach, device characterization and validation for this novel device design.