复杂飞机结构裂纹萌生寿命确定的工程方法

采用静拉伸应变测量试验的方法,确定了典型飞机复杂结构在载荷作用下的应变分布,并准确判断出其疲劳危险部位。对典型飞机复杂结构模拟件进行了等幅加载疲劳试验,并在疲劳试验过程中采用着色探伤方法测得了疲劳裂纹扩展数据。在此基础上,提出并建立了一种适用于确定复杂结构疲劳裂纹萌生寿命的工程方法,包括疲劳裂纹萌生寿命反推法和含有不确定寿命样本的统计推断方法。根据该方法对试验样本疲劳数据进行处理得出了裂纹萌生中值寿命及其在95%置信水平下的单侧置信下限。

An Engineering Method for Estimating Crack Initiative Life of Complex Aircraft Structure

The distributions of stain in the typical complex aircraft structure were determined and the fatigue critical locations were determined accurately by using the static stretch testing and strain measure method.The simulate components of the typical complex aircraft structure were conducted a identical range loading fatigue testing.And the fatigue crack propagation data were obtained by using colouring method in the course of fatigue testing.On this basis,an engineering method that is suitable for evaluating the crack initiative life of the complex structure,including the converse method for estimating the fatigue crack initiative life and the statistical inference method for the sample which contain indefinite life specimen was put forward and established.The mean life of crack initiation and its lower limit of unilateral believable degree under the believable degree level 95% were obtained by applying this method to analyze the fatigue testing data.