Dynamic Analysis of Nonproportional Damping Structural Systems Time and Frequency-Domain Methods (original) (raw)

Abstract

Structural systems composed of structural elements with different characteristics as NPP and soil and fluid-structure interaction systems present considerable nonproportional damping. The assumption of uncoupled modal equations with assumed modal damping ratios can lead to substantial errors in the dynamic analysis results of those systems. Therefore that assumption is not anymore accepted by the nuclear industry. Appropriate and more rigorous methods for the dynamic analysis of structural systems with nonproportional damping should be developed. In this paper pseudo-force mode superposition methods are developed which consider the nonproportional damping effect through a pseudo-force term in the RHS of the modal equations. These equations are then iteratively solved. The methods presented are considered in time and frequency-domain. The frequency-domain version is very suitable for the analysis of systems with hysteretic damping and frequency-dependent properties. Examples of time ...

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