发动机飞行载荷测量应变计布置方案分析

Placement scheme analysis of strain gauge for engine flight load measurement

针对发动机风扇机匣飞行载荷的测量需求,开展了机匣应变计布置方案研究。利用应力摩尔圆得出了通过若干半桥叠加不能获取主应变的结论。根据应变和载荷的线性叠加原理,通过分析典型飞行条件下发动机受力情况,将机匣承受的静载荷归为拉压力、扭矩、剪切力、弯矩载荷、压差载荷五种载荷类型,采用合理的组桥方式可消除其他载荷对目标载荷应变的影响,确定了前四种载荷类型的应变布置方案。给出了后续载荷的测量分析方法:以地面试车、稳定平飞时的载荷数据为基准点,根据受力分析结论,建立不同状态发动机参数与应变之间的关系。这些分析和结论可为应变改装提供指导,也可为其他应变测试提供了参考和借鉴。

Aiming at the flight load measurement requirements of engine fan casing,the placement scheme of casing strain gauge is studied. The conclusion that the principal strain can’t be obtained by superposition of several half-bridges is obtained by using the stress Mohr circle. According to the linear superposition principle of strain and load,the static loads on the casing is classified into five load types: tension,torque,shear force,bending moment load and differential pressure load by analyzing the stress of the engine under typical flight conditions,the influence of other loads on the target load strain can be eliminated by using the reasonable combination bridge way,and the strain placement scheme of the first four load types are determined. The measurement and analysis method of the subsequent load is given: based on the load data of ground test and stable level flight,the relationship between engine parameters and strain in different states is established according to the conclusion of force analysis. These analysis and conclusions can provide guidance for strain refitting,and also provide reference for other strain testing.