Identification of Modal Parameters Using the ST-EFDD Method for a Time-Varying Mass System in a Corn Combine Harvester
摘要
This research introduce a short time-enhanced frequency domain decomposition (ST-EFDD) method for accurate identification of modal parameters, including eigenfrequencies and damping ratios, in mass time-varying structures.
MethodsThe method integrates segmented processing with frequency-domain analysis to enhance local vibration characterization, improves computational efficiency via adaptive window sizing, and is validated on both a simply supported beam and a corn combine harvester under mass time-varying conditions.
ResultsThe results reveal a clear decay trend in the eigenfrequencies of the corn combine harvester, with defined variation ranges across 12 identified modes. Statistical analysis of the damping ratios extracted via ST-EFDD shows minimal temporal fluctuation across modal orders.
ConclusionThe modal characteristics of the mass time-varying beam were identified using both ST-SSI and ST-EFDD methods. Comparative results indicate that ST-EFDD offers superior performance under conditions with limited excitation sources. Accordingly, ST-EFDD is applied to the corn combine harvester system to extract modal parameters during field operation, where the structure is subject to complex excitations.