SUN Pan-xu, YANG Hong, LIU Qing-lin. COMPLEX MODE SUPERPOSITION METHOD OF HYBRID STRUCTURE SEISMIC RESPONSES BASED ON DYNAMIC CHARACTERISTICS[J]. Engineering Mechanics, 2020, 37(11): 69-82. DOI: 10.6052/j.issn.1000-4750.2019.12.0723
Citation: SUN Pan-xu, YANG Hong, LIU Qing-lin. COMPLEX MODE SUPERPOSITION METHOD OF HYBRID STRUCTURE SEISMIC RESPONSES BASED ON DYNAMIC CHARACTERISTICS[J]. Engineering Mechanics, 2020, 37(11): 69-82. DOI: 10.6052/j.issn.1000-4750.2019.12.0723

COMPLEX MODE SUPERPOSITION METHOD OF HYBRID STRUCTURE SEISMIC RESPONSES BASED ON DYNAMIC CHARACTERISTICS

  • The damping matrix of a hybrid structure of different material damping characteristics is difficult to determine. By the aid of mathematical simplicity, Rayleigh damping model is widely used in the construction of damping matrix of a hybrid structure. But the calculation precision of Rayleigh damping model is affected by the choice of reference frequencies. Thusly, a calculation method of Rayleigh damping coefficients is proposed based on the characteristics of structural dynamic responses. The corresponding complex mode superposition method is also realized. The damping coefficients are determined based on the natural frequencies of the first two modes when the structural transient responses are calculated. The damping coefficients are determined based on fundamental frequency and certain frequency when the structural steady state responses are calculated. The certain frequency is the natural frequency close to external excitation frequency. According to the spectrum characteristics of seismic wave, a Rayleigh damping model is obtained based on the predominant frequency of seismic wave. Combined with the linear assumption of earthquake acceleration, a complex mode superposition method of hybrid structure is realized. The harmonic frequencies of seismic wave could be obtained by trigonometric series. Another Rayleigh damping model is developed based on the harmonic frequencies, and the corresponding complex mode superposition method is proposed. The cases show that the proposed method could avoid the arbitrariness of selective modes based on traditional methods. The calculation error of the proposed method is small. Compared with the complex mode superposition method based on the predominant frequency of seismic wave, the computational amount of complex mode superposition method based on the harmonic frequencies is larger, but with higher calculation accuracy and wider range of application.
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