HHT-Based Artificial Seismic Accelerograms Generation

Abstract

Part 11: Simulations and Fuzzy ModelingInternational audienceA new efficient approach for generating spectrum-compatible seismic accelerograms is proposed. It is based on the Hilbert-Huang Transform (HHT); one natural seismic accelerogram is decomposed into frequency and amplitude components. The components are appropriately modified to synthesize the artificial seismic accelerogram that appears to have compatible acceleration spectrum with the natural seismic accelerogram. The HHT is an adaptive signal processing technique for analyzing nonlinear and non-stationary data such as seismic accelerograms. With HHT a seismic accelerogram is decomposed into a finite and small set of components. These components have well defined instantaneous frequencies, estimated by the first derivative of the phase of the analytic signal. The method is tested using twenty natural seismic records and a comparison with two established methodologies is provided

Artificial accelerograms composition based on the CEEMD

“…Several recently reported studies employ the HHT to generate spectrum-compatible seismic accelerograms (Ni et al, 2011, 2013; Vrochidou et al, 2012, 2013; 2014a, 2014b). In methods proposed by Ni et al (2011, 2013), a set of six natural seismic records is essential in order to generate an artificial spectrum-compatible accelerogram.…”

“…The instantaneous values of amplitude are scaled with the proper parameters optimized through a GA so enable the artificially generated accelerograms to be spectrum-compatible with the initial seismic signal. In Vrochidou et al (2014b), the instantaneous amplitude values of the SMD are scaled and the associated instantaneous frequency values of the SMD are subjected to smoothing and addition of Gaussian noise.…”