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Viscous Heating of Fluid Dampers Under Wind and Seismic Loading: Experimental Studies, Mathematical Modeling, and Design Formulae

Black, Cameron J.; Makris, Nicos

UCB/EERC-2006/01, Earthquake Engineering Research Center, 2006-03-01, pdf (400 E177 2006-01)

The report presents an approximate energy balance formulation which simplifies the problem of viscous heating of fluid dampers to the solution of one-dimensional energy equation. Three fluid dampers of different size with force outputs of 3, 15 and 250 kips at maximum design velocities were instrumented and tested under various amplitudes and frequencies. Temperature histories at different locations along the damper casing and within the silicone fluid that undergoes the shearing action were recorded. Experimental data from testing the 250 kip damper under small-stroke (wind) loading shows that a single closed form solution of the linearized one-dimensional energy equation is capable of predicting the temperature rise at different locations along the damper. Under long-stroke (earthquake loading) motion, data suggest a two parameter law, an extension of Newton's law of cooling, that provides a good estimation of the internal temperature of the silicone oil once the external temperature on the damper casing is known, a task easily accomplished in the field.

Available online: (11 MB)