Experimental test and validation of a direction- and displacement-dependent viscous damper

Semiactive devices offer the opportunity to customize the device response, and thus to customize the overall structural hysteretic response. However, they are actively controlled and thus entail a significant addition of complexity and potentially cost for the added performance. This study introduces the concept, design, and experimental validation of a direction- and displacement-dependent (D3) device using viscous damping. D3 devices provide viscous damping in any individual or multiple quadrants of the force-displacement response. Previously only achievable using semiactive devices, this research presents an entirely passive and thus more robust and lower cost device. The D3 device design concept is presented and experimental tests are undertaken on a prototype device. Sinusoidal displacement inputs provide a range of velocity inputs and device forces used to characterize the damping behavior of the prototype and illustrate the ability to provide controllable viscous damping in any single or multiple quadrant(s) of the force-displacement response. Performance is characterized by device design parameters. The overall results provide a proof of concept for a new class of relatively low-cost passive devices that enable customized hysteretic behavior for any given structural application.