Abstract:To address the issue of single evaluation criteria in time-domain extrapolation threshold selection, a multi-criteria threshold selection method based on CRITIC-VIKOR is proposed. The principal component signals of the dynamic stress data of the vehicle undercarriage are obtained through empirical mode decomposition. The optimal threshold range is preliminarily determined using the exceedance mean function plot method. Within this interval, the optimal threshold is selected using the CRITIC-VIKOR method based on each inspection criterion. Data exceeding the threshold is extracted for generalized Pareto distribution (GPD) fitting, and random loads are generated using the fitting parameters to replace the original threshold-exceeding data for time-domain extrapolation. The damage caused by the extrapolated dynamic stress data is then calculated. The results indicate that compared to actual measurement data, the damage errors calculated by linear extrapolation, rain-flow extrapolation, and time-domain extrapolation are 0.59%, 0.20%, and 0.18%, respectively. This demonstrates the scientific validity and accuracy of the time-domain extrapolation method.