Fatigue crack is one of the most important forms of damage that cause the failure of aircraft structures,and timely and effective online monitoring and diagnosis of fatigue crack propagation is of great significance to ensure the integrity and safety of the structure.Due to the complex service environment and operating conditions,these time-varying factors are coupled with each other,which are easy to cause obvious uncertain changes in the characteristics of monitoring signals,and seriously affect the reliability of structural damage diagnosis.Aiming at the reliable evaluation of aircraft structural damage under the influence of time-varying service conditions,a method of structural damage quantitative diagnosis based on guided wave health Hidden Markov model(HMM)was proposed.In this method,the guided wave signal characteristics under the health state of aircraft structures are characterized by HMM model,and the structural damage state is represented by the probabilistic migration relationship between the real-time monitoring of guided wave signal characteristics and HMM model,so as to realize structural damage warning and quantitative diagnosis.In the batch bolts of fatigue crack propagation experiments verified the method,the results show that the damage to the early warning and diagnosis of average error is 0.4 mm,damage quantitative diagnostic assessment of maximum average absolute error is 0.9 mm,shows that the method can timely early warning and monitoring of fatigue cracks in structure,reliable continuous quantitative diagnosis for the crack extension.
关键词
结构健康监测/导波/时变条件/损伤定量诊断/隐马尔科夫模型/似然概率
Key words
structural health monitoring/guided waves/time-varying conditions/quantitative diagnosis of injuries/hidden Markov model/likelihood probability
维普
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