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To improve overall customer experience, it is imperative to minimize the noise levels inside agricultural equipment cab. Up-front prediction of acoustic performance in product development is critical to implement the noise control strategies optimally. This paper discusses the methodology used for virtual modeling of a cab on agricultural equipment for prediction of interior noise. The Statistical Energy Analysis (SEA) approach is suitable to predict high frequency interior noise and sound quality parameters such as articulation index and loudness. The cab SEA model is developed using a commercial software. The structural and acoustic excitations are measured through physical testing in various operating conditions. The interior noise levels predicted by the virtual model are compared with the operator ear noise levels measured in the test unit. The resultant SPL spectrum from SEA correlates well with the test.

Engine is one of the major sources of noise in off-highway vehicles. Muffler plays an important role in attenuating the noise emitted by engines. Mufflers are designed to provide maximum noise attenuation without significantly affecting the back pressure. Inlet and outlet arrangements of muffler are proposed based on engine exhaust system and engine compartment design. Multi-inlet and/or multi-outlet mufflers are used based on the needs. This paper details the procedure used for evaluation of transmission loss of a muffler on off-highway vehicle which has two-radial inlets and one axial outlet. 3D simulation is used to obtain the transmission loss parameters. To validate the models, virtual analysis is carried out in two steps. In the first step, one inlet is open to source while the other is blocked and termination at the outlet is anechoic. In the second step, the open and closed inlets are swapped.

A typical cab used on agriculture machines is made up of a metal frame structure with large enclosing panels of glass, plastic, and metal. Acoustic treatments such as coatings, textiles and foams are used within the cab for aesthetics but also to mediate undesired noise. To develop effective designs for the cab to combat noise, accurate tools for measurement, and predictive methods for sound transmission loss are needed. This paper focuses on Sound Transmission Loss (STL) of the rear upper panel of a cab used in agriculture machines. Results from CAE based tools such as Statistical Energy Analysis (SEA), Finite Element Analysis (FEA) and Hybrid FE-SEA methods are compared to measurements. The panel studied included features such as curvature, deep drawn beads with a glass window and a damping coating. The simulation results are refined by incorporating methods for accurate modeling of ribs stiffness, curvature effect and radiation efficiency by synthetic modal approach.