某型飞机局部结构改装振动响应增量预估

Prediction of Vibration Response Increment of Some Airplane with Local Structural Modifications

研究了某型飞机局部结构改装振动响应增量预估问题。根据对原型飞机和改装结构──加装天线罩的分析，提出了振动响应增量预估的分析原理、方法与技术路径，即以天线罩引起的气动载荷为输入，以天线罩及周围机身为受激对象，计算或测量天线罩上及机身内外某些点的振动响应增量。为此，本文通过缩尺模型的吹风试验，测量了天线罩上的脉动气动载荷；通过地面振动试验，测量了改装结构的频响函数；并进行了计算预估与模拟加载响应测量预估。预估结果对评估放飞起到重要作用，试飞结果与评估结论一致。

Investigates the prediction of vibration response increment of some airplane with local structural modifications. Based on the analysis of the original airplane and the modified structures-added outer-shells, the principle, the method and technique route for the prediction have been proposed with aerodynamic loads produced by the added outer-shells as excitations and the added outer-shells and the surrounding fuselage body as theexcited objects. The vibration response increments of the points on surrounding shells and the points inside the airplane chamber are calculated or measured. For this purpose,the aerodynamic loads of outer-shells are measured by wind-tunnel test on a model, the frequency response functions of the modified structure are measured in ground vibration test and the predictions based on computer calculation and simulation loading are performed.The results of prediction have played an important role in the assessment of the flying test. The results of the flying test are coincident with the conclusions of the assessment.