Root Cause Analysis of Drive Noise in an Agriculture Machine End Unit

Abstract

<div class="section abstract"><div class="htmlview paragraph">In any off-highway machinery throughout the product development cycle, noise is considered an important characteristic. This characteristic drives the product quality, safety, and productivity and meets the homologation requirements. Identifying the critical noise source and finding out the true root cause of the noise source is a very critical element in improving the design to reduce the noise levels. A systematic approach is needed to understand the behavior of the system, which can be achieved through collaborative efforts among the analysis, design, and testing teams.</div><div class="htmlview paragraph">This paper describes how virtual analysis helps to determine the main source of noise radiation in the audible frequency range of the human ear. The sound pressure level (SPL) in the test data at the end unit drive of an agriculture machine showed high peaks at a few frequencies in the critical frequency range. The spectral content remains the same regardless of the backshaft speed. The noise goes away when the tensioner sprocket center nut is loosened. In the initial stage, the accuracy of the end unit drive finite element (FE) model is ensured by comparing the virtual driving point impedances with test data for both loose and tight nut conditions. In the later stage, the acoustic finite element method adaptive order (FEM AO) model is developed [<span class="xref">1</span>] and correlated with test data of SPLs. In the final stage, panel contribution analysis is carried out to determine the critical noise-radiating component. This validated model will be confidently used to improve the design further.</div></div>