Analysis and Simulation for Planetary Gear Fault of Helicopter Based on Vibration Signal

Fault diagnosis for helicopter’s main gearbox based on vibration signals by experiments always requires high costs. To solve this problem,a helicopter’s planetary gear system is taken as an example. Firstly,a simulation model is established by McFadden,and analyzed under ideal condition. Then this model is developed and improved as the delay-time model of the vibration signal which determines the phase-change of sidebands when the system is running. The cause and change-rules of planetary gear system’s vibration signal are analyzed to establish the fault diagnosis model.At the same time,the vibration signal of fault condition is simulated and analyzed. This simulation method can provide a reference for fault monitoring and diagnosis for planetary gear system.     

某新型大口径机枪射击稳定性计算与仿真分析

为研究某新型大口径机枪在不同地面环境下的射击稳定性,分别建立了枪架稳定性模型与整枪的动力学模型。得出在粘土地和水泥地环境下的稳定条件,并计算了机枪稳定所需的抵肩力;建立了其某个击发动作的动力学模型,采用仿真软件计算出了不同地面环境下的枪口位移响应结果。通过不同地面环境下枪口响应的比较以及与某相似型机枪的横向对比,证明了该枪对不同地面具有良好的适应性及射击稳定性,为大口径机枪的稳定性论证及改进奠定了理论及实践基础。