用于直升机舱内降噪的主减支撑吸振技术研究

目的 通过控制主减速器结构声，进一步实现直升机舱内降噪。方法 在主减支撑结构上进行吸振设计，从根源上抑制齿轮振动向机身传播。基于某直升机，利用传递矩阵法，建立支撑结构/吸振器的动力学模型，进一步结合有限元法建立支撑结构/舱段结构/声场的声振耦合系统动力学模型，验证该技术的中高频减振和降噪性能。在此基础上，分析吸振频率、质量和阻尼对支撑结构振动传递特性的影响规律。根据某直升机的降噪需求，设计得到一组满足需求的样例参数，并开展声振耦合仿真分析。结果 在主减支撑结构上附加总质量为4 kg的吸振器结构，即可实现舱内目标频率降噪超过35 dB。结论 主减支撑结构吸振设计可有效控制舱内中高频主减结构声。

Vibration Absorption Technology on the Support Structure of Main Gearbox for Helicopter Cabin Noise Reduction

The structure-borne noise from main gearbox is one of the main noise sources in helicopter cabin. In order to realize the noise control, the vibration absorption design on the supporting structure of the main gearbox is proposed to suppress the vibration transmission from the gearbox to the fuselage. To verify its performances, based on a certain helicopter, the dynamic model of the supporting structure with the vibration absorber was established based on the transfer matrix method. Then, the dynamic model of the vibro-acoustic coupling system, including the supporting structure, the fuselage, and the cabin sound field, was established. On this basis, the influence of the vibration absorption frequency and weight on the vibration transmission characteristics of the supporting structure was analyzed. Furthermore, according to the requirements of a certain helicopter, a set of sample parameters was chosen, and the vibro-acoustic coupling simulation analysis was carried out. The analysis results shows that the vibration absorption can effectively control the structure-borne noise from main gearbox and the noise reduction of the target frequency can be more than 35 dB with a total weight of 4 kg, which providing a technology support for the schematic design of noise reduction in helicopter cabin.