Definitions and correlation analyses for background response and resonant response

It is an important problem in wind engineering to define background response, resonant response, and to analyze the correlation between their components for multi-degrees-of-freedom system. On the basis of modal acceleration method, background response and resonant response are strictly defined. Furthermore, it is deduced to calculate background response and resonant response and the correlation coefficient between these two components in frequency domain. It is found that response spectrum under fluctuating wind consists of background response spectrum, resonant response spectrum and the coupling spectrum, and the exact method is deduced to combine these three components. According to the method, three response components of wind-induced response of a single layer reticular shell is analyzed, and the results show that the correlation coefficients between background response and resonant response for all nodal displacements are around [-0.3, -0.l]. and it will overestimate the exact response 3%-10% if this correlation is neglected.