A condition control-based dual-reliability evaluation for structural health monitoring

It is well recognized that Structural Health Monitoring (SHM) reliability evaluation is a key aspect that needs to be urgently addressed to promote the wide application of SHM methods. However, the existing studies typically transfer the Non-Destructive Testing/Evaluation (NDT/E) reliability metrics to SHM without a systematic analysis of where these metrics originated. Seldom attentions are paid to the evaluation conditions which are very important to apply these metrics. Aimed at this issue, a new condition control-based Dual-Reliability Evaluation (Dual-RE) method for SHM is proposed. This new method is proposed based on a systematic analysis of the whole framework of reliability evaluation from instrument to NDT, and emphasis is paid to the evaluation condition control. Based on these analyses, considering the special online application scenario of SHM, the proposed Dual-RE method contains two key components: Integrated Sensor-based SHM-RE (IS-SHM-RE) and Critical Service Condition-based SHM-RE (CSC-SHM-RE). IS-SHM-RE evaluates the reliability of integrated SHM sensor and system themselves under approximate repeatability conditions, while CSC-SHM-RE assesses SHM reliability under the dominant uncertainties during service, namely intermediate conditions. To demonstrate the Dual-RE, crack monitoring by using the Guided Wave-based-SHM (GW-SHM) on aircraft lug structures is taken as a case study. Both the crack detection and sizing performance are evaluated from accuracy and uncertainty.