飞机抖振响应数据处理及分析方法

Method of data processing and analysis for aircraft buffet response

为了编制抖振疲劳谱、估算抖振疲劳寿命等,必须预先对时域的抖振响应数据进行处理与分析。考虑到抖振响应的随机特性,特别是其显著的分散性,建立了统计模型来对其分析处理。针对同一飞行状态下数据仓中的抖振响应数据,将其划分为若干子数据块,以子数据块中数据统计特征来描述对应子数据块均方根下的响应分布情况,而以对应飞行状态下各子数据块的均方根分布情况来描述该状态下抖振响应的总体分布趋势以及选择其关键响应状态水平。首先,采用威布尔分布假设,运用极大似然估计法对子数据块的数据进行分布参数估计,并给出了分布假设的检验方法;然后,采用"三步进"经验函数来描述抖振响应均方根的分布规律。在所研究的基础上,根据给出的抖振数据处理与分析结果使用流程,即只需根据确定的几个关键均方根水平,定位到相应的子数据块,再结合子数据块数据的统计模型得到对应飞行状态下的响应分布,就可用于飞机设计与强度校核。由实际飞行试验抖振数据的处理与分析表明,此方法具备一定的合理性。

Aiming at developing buffet fatigue spectrum,predicting life and so on,the method of data process and analysis was proposed under a unified flight condition and using the probabilistic model to decrease data scattering.The dynamic time histories were split into several blocks by using a suitable time range.The statistical characteristics of each block were investigated to express the response distribution with its corresponding root mean square,while the root mean squares of different blocks were used for representing RMS variation.The Weibull distribution was chosen as the assumption of response distribution in each block and its parameters were obtained though the method of maximum likelihood estimation.The method of distribution test was proposed to form a criterion for determining its accuracy.Then an empirical step function was introduced to represent RMS variation under the given flight condition.According to the given flow chart of application,it is available to carry out the work of aircraft design,strength certification and so on.The result of processing flight test data proves that the method is valid and available for the buffet issues.