Pressurized Sand Damper for Earthquake and Wind Engineering: Design, Testing, and Characterization

Abstract

This paper presents the development, testing, and characterization of an innovative low-cost fail-safe sustainable energy-dissipation device in which the material surrounding the moving piston and enclosed within the damper housing is pressurized sand. The proposed sand damper does not suffer from the challenge of viscous heating and failure of its end seals, and it can be implemented in harsh environments with either high or low temperatures. Its symmetric force output is velocity-independent, and it can be continuously monitored and adjusted at will with standard commercially available strain gauges installed along the post-tensioned rods that exert the pressure on the sand. Component testing at various levels of pressure, stroke amplitude, and cycling frequency show that the proposed pressurized sand damper exhibits stable hysteretic cyclic behavior with increasing pinching at larger strokes. The paper examines the fidelity of an eight-parameter Bouc-Wen hysteretic model capable to model pinching and concludes that the proposed hysteretic model is able to capture the pronounced pinching of the hysteretic behavior at larger stroke amplitudes. Four of the eight parameters of the proposed hysteretic model can be determined a priori from physical arguments; therefore, only the remaining four parameters need to be determined from nonlinear regression analysis.