一种直升机主减机匣疲劳试验安装平台改进设计方法

Method for design improvement of the fatigue test platform of helicopter's main gear-box

直升机主减机匣承受来自主桨叶的升力、剪力、弯矩和转矩等载荷。某直升机传动系统主减机匣通过安装腿直接与机体平台相连,来自桨叶的所有载荷通过4个安装腿传递至机体结构。因此,安装腿成为主减机匣的疲劳关键部位。在相同载荷水平下,外场试飞中主减机匣前腿部位的应变值比疲劳试验台测试值大20%,二者存在较大的差异。文中在不改变载荷和加载条件下,通过降低疲劳试验安装平台的刚度,提高主减机匣腿部的疲劳试验应变测试值,从而获得更高的疲劳极限,为试飞安全提供技术支持。

The helicopter＇s main gear-box bears the lift force, shear force, bending moment, and torque from the main rotor. Some main gear-boxes are connected with the helicopter though their mounting legs. All the loads from the main rotor are transferred to the helicopter via four mounting legs. Thereby, the mounting legs of the main gear-box are key parts of fatigue. Under the same load level, the strain of the main gear-box＇s front mounting leg obtained in the flight test is 20% larger than that obtained in the fatigue test. These values are vastly different. In this paper, with the load and loading conditions unchanged, measures are taken to decrease the stiffness of the fatigue test platform and increase the fatigue test strain of the mounting legs, in order to get a higher fatigue limit. These improvements provide technical support for a safe flight test.