Modeling Method of Element Rayleigh Damping Applied to System Consisted of Structures with Multiple Damping Properties

Abstract

Detailed three-dimensional FEM models have been used for seismic analysis with the growth of computer performance. In seismic analysis using the FEM models, Rayleigh damping and element Rayleigh damping have been commonly used; however, it is not necessarily clear how to model those damping in performing seismic analysis of a system consisted of structures with multiple damping properties. The purpose of this study is (i) to propose modeling method for element Rayleigh damping applied to the above-mentioned system and (ii) to examine effectiveness of the proposed method. In the proposed method, coefficients of element Rayleigh damping are determined by using weighted least-squares method, and the weighting factors are based on products of modal participation function and response spectrum of input seismic motion. Additionally, in order to examine effectiveness of the proposed method, seismic analyses were performed by using lumped-mass analysis model with the proposed method and the conventional methods. Analysis results were compared with the ones given by the strain energy proportional damping, and error rates were evaluated. As a result, average error rate of the proposed method was 6 %, and that was smaller than those of the conventional methods. Thus, it is concluded that the proposed method is effective for seismic analysis of the system consisted of structures with multiple damping.

Modeling method of element Rayleigh damping for the seismic analysis of a 3D FEM model with multiple damping properties

“…The previous study (Onitsuka et al., 2015) examined the effectiveness of the proposed method for a simple lumped-mass model, but the effectiveness for a more complicated 3D FEM model was not examined. The proposed method has been improved to be applied to 3D FEM models with multiple damping properties.…”

“…This means that Wang’s method does not always accurately model the damping properties of the structures because the structures are not generally considered to have damping characteristics that are proportional to frequency. Our group previously proposed a method for determining the coefficients of element Rayleigh damping (Onitsuka et al., 2015).…”

“…In the previous study (Onitsuka et al., 2015), the effectiveness of the method was evaluated in a simple lumped-mass model composed of mass and beam elements with multiple damping properties. The effectiveness of the method in 3D FEM models was not evaluated.…”

Evaluation of load-carrying capacity of full-scale falling protection net using distinct element method

“…For reference, utilizing the Rayleigh damping model, the period of vibration that corresponds to the low-pass filter T L and the high-pass filter T H is coefficients α and β, respectively. The relationship between T L , T H , and coefficients α and β is as follows (Onitsuka et al, 2015) T L = βπ (10a)…”