This study investigates noise detection and damping-based noise mitigation strategies for cavity structures, with a specific focus on addressing noise issues in the conveyor trough of combine harvesters. Despite its practical significance, research on the noise generation mechanisms, transmission paths, and control measures for conveyor troughs remains limited, particularly under varying operational conditions. To bridge this gap, this work integrates experimental measurements with numerical simulations to systematically analyze and optimize the noise reduction performance of the conveyor trough. Noise measurements were conducted using the sound intensity method, revealing sound pressure levels in the range of 93–95 dB. Frequency spectrum analysis identified key noise sources and dominant frequency components. Finite element analysis (FEA) and vibration modal testing were performed to uncover critical noise-inducing factors, including chain meshing impacts and structural resonances. Based on these findings, a damping optimization strategy was proposed by incorporating constrained damping layers to attenuate vibration and reduce noise in targeted frequency bands. The effectiveness of this approach was validated through multiple coherence analysis, which confirmed significant suppression of structural vibration noise in the 0–500 Hz range, while experimental results showed that the optimized conveyor trough structure achieved a maximum reduction of 0.4071 dB in continuous equivalent A-weighted sound pressure under load conditions. This research provides a comprehensive methodology for noise control and structural optimization of conveyor trough systems, offering valuable theoretical and practical insights for enhancing the operational comfort and environmental performance of combine harvesters.

In the mechanized harvesting of root vegetables, loosening is a key factor that restricts harvesting efficiency. Existing mechanical loosening methods have poor loosening effect and high operational resistance. Therefore, more efficient agricultural machinery is needed to reduce energy consumption and improve harvesting efficiency. To this end, based on the efficient excavation mechanism of the first claw toe structure of the mole cricket forefoot, this paper designs the shovel tip structure of the bionic loosening shovel by extracting its contour curve and analyzing the excavation process, constructs the working resistance model and dynamic balance equation of the bionic loosening shovel, determines the optimal working parameters through two-factor and three-level orthogonal simulation experiments, and carries out comparative simulation experiments with the common loosening shovels. The results show that the optimal combination of operating parameters for the bionic loosening shovel is the rotational speed $\omega$ = 5 r/s and the traveling speed of the whole machine v = 0.5 m/s. The disturbance performance of the 31 bionic loosening shovel on the soil is improved by 51.59% compared with that of the common loosening shovel, and the working resistance is reduced by 12.17%. The results of this study proved that the bionic structure of the first claw toe of the mole cricket can significantly improve the working performance of the loosening shovel, which can effectively improve the cutting effect of the soil and reduce the energy loss during the working process.