Work

Root cause analysis of noise transfer in an entire tractor system using multi-layer operational transfer path analysis

Year: 2024

Type: article

Abstract: Tractor noise and vibrations adversely affect the health of operators, reduce work efficiency, and interfere with the creation of a comfortable working environment. Electric-powered next-generation tractor systems lack masking effects in engines. Moreover, as various excitation sources contribute to noise, rapid causal analysis of numerous transfer paths is necessary. This paper proposes an operational transfer path analysis (OTPA) network using a multi-layer transfer function matrix and a contribution calculation method. A root cause analysis of the noise transfer considering the entire tractor system is performed using only the response signals. Acoustic and vibration signals were acquired from 83 sensor channels on the sources and transfer paths of the tractor, and an analysis network was constructed using air- and structure-borne paths. The signals predicted by the developed OTPA model matched the overall response level and frequency domain characteristics of the sound pressure signals measured from an actual tractor. Additionally, air- and structure-borne noise contributions were quantitatively evaluated according to the frequency, wherein the structure-borne noise was dominant. The analysis results indicate that the floor panel of the tractor cab exhibits a high contribution to the 4th-order noise in the engine, and the front glass comprises a structural mode in the 684 Hz band. The contribution from the rear part of the mounts, which serve as the dominant paths for transmitting vibrations to the tractor cab, is higher than that from the front part. This difference warrants a separate design for the front and rear mounts. The contribution of air-borne noise increases as the engine speed increases. The air-borne noise is primarily contributed by the wheel noise, with the rear wheels contributing more than the front wheels. These study findings can aid the development of the design of tractors for enhanced performance.

Source: Smart Agricultural Technology

DOI: 10.1016/j.atech.2024.100754