Estimating the Effect of Noise on Various ARMA-Based Damage-Sensitive Features

Vibration-based damage-sensitive features (DSFs) are a useful diagnostic tool in condition assessment of structural systems. While many DSFs are designed to be insensitive to random noise, in practice the presence of measurement noise can impede the identification of structural damage. In this study, four DSFs for use with autoregressive moving average (ARMA) models were examined with signal-to-noise ratios (SNR) ranging from 40 to 0.5 dB to evaluate the accuracy of damage estimation for increasing levels of noise. All structural responses were generated from a simulated cantilever beam model. Student t-tests were utilized to compare DSFs between the healthy state and an unknown state. The results indicated that the Cosh spectral distance DSF outperforms the other DSFs for SNRs less than 20 (i.e., greater than 1% of noise added). These results are consistent with prior work that demonstrated the robustness of the Cosh spectral distance as a DSF.