Abstract

Earth-moving machinery often produce A-weighted overall sound levels that can vary between 95 to 105 dBA, which may exceed regulatory levels that the operators and workers experience. This can have severe and permanent consequences on their hearing, notably in the case of improper use or lack of protective gears. The regulations imposed on such machines follow standards that depend on the market location and the function of the machinery. One such standard is the ISO 6393 that measures the noise emitted to the environment and the operator in A-weighted sound overall sound power level, thereby providing safety regulations under stationary test conditions. The Ditch Witch brand under The Charles Machine Works Inc. has relied on PowerFLOW’s Lattice-Boltzmann framework of high fidelity and realistic aero-acoustic simulations consistently over the last decade. With similar intentions, Ditch Witch has collaborated with SIMULIA to perform acoustic evaluations on a skid-steer machine as per ISO 6393 norms, to estimate fan-noise trends for different fan-shroud design variants. The study uses a single environment automated workflow embedded on the SIMULIA Cloud platform to firstly, create the simulation model, secondly, submit the design iterations, and finally analyze the results, which allows the democratization of standardized acoustic evaluations to users with all levels of expertise in the subject. The study starts with a set of fan-shroud designs optimized for cooling airflow through the heat exchangers, subjected to virtual acoustic tests that follow the norms of ISO 6393 testing conditions. This presentation will focus on the design changes in the cooling package that contributed to the different trends in the fan-noise levels, and how the benefits were leveraged in the latter stages of product development. The study ends with a comparison between the virtual tests and prototype tests at different stages of the design cycle allowing validation of the simulation results.