Experimental Measurement of Dynamic Characteristics of Structural Units

Abstract

The aim of this study is to investigate and optimize the dynamic properties of an entire structural unit. Using modal analysis and experimental measurements of the propulsion system, natural frequencies with close agreement were identified. The drive was able to work within the frequency range during start-up and normal operation, but due to various influences, including the inherent oscillations of structural elements, complex dynamic phenomena occurred. The presence of a conveyor with rubber and plastic wheels also affected the results. Important information on the input shaft, tooth frequency, driveline oscillation and output shaft was obtained. Research has identified resonant frequencies and increased drive oscillation that are created by the interaction between the input shaft and tooth frequency. The significant frequency of bent screws in the conveyor pipe affects the shafts and the drive screw, which in turn causes problems with material fatigue and microcracks. Corrective measures include the possibility of replacing or balancing the screw and increasing the diameter of the pipe. Regular monitoring and diagnostics have a preventive nature and serve to minimize serious consequences. Implementing a controller with a PID system offers the potential to suppress oscillations and improve dynamic and strength characteristics, while accurate calibration of this implementation is of key importance.