Rayleigh coefficients for series infrastructure systems with multiple damping properties

Abstract

The Rayleigh damping matrix formulation is a commonly implemented means for the representation of intrinsic damping in many finite element programs. However, methods for specifying the Rayleigh mass and stiffness-proportional coefficients based upon individual components’ unique dissipative properties are ambiguous and rely heavily upon engineering judgment. An alternative linear hysteretic constitutive modeling methodology is used to represent multiple dissipative properties in example base-isolated series frame structures; the resulting displacement data are verified against a second alternative method involving weighted modal time history analysis. A methodology for the determination of Rayleigh coefficients for series systems dominated by low-frequency behavior is then developed based upon a hybrid of the two independent alternative methods. The displacement data from the proposed Rayleigh damping methodology are calibrated against the linear hysteretic constitutive modeling methodology, with the results showing close agreement.