Monitoring of crack propagation using a cluster of piezo-sensors

Abstract

This paper describes the investigation of a probabilistic method for crack propagation monitoring in plate- or shell-like structures, which utilizes a cluster of passive piezoelectric sensors. The method allows for the determination of the crack tip location and stress intensity factor (SIF) of a relatively long crack in the vicinity of the cluster, with predetermined or specified accuracy of monitoring. An analytical deterministic model for the response of a piezo-sensor located in the vicinity of a crack tip was developed, based on previously published work. Probabilistic characteristics of the piezo-sensor response were obtained experimentally for a wide range of loading conditions. The analysis is derived from a solution of the inverse problem for the cluster and Monte-Carlo simulations utilising the experimentally obtained probabilistic characteristics of the piezo-sensor response. If the crack path can be identified beforehand, then the analysis provides the optimal cluster design for monitoring the crack extension with a required accuracy. Also, a series of clusters can be used to monitor large crack advances.