Vehicle's components experience a variety of small to large strains during its operations. Monitoring a set of only large strains of the components is preferable for critical analysis of structural health of the vehicle. For data of all strain history including smaller amplitudes as a function of time require huge data storage system which in turn requires large power and communication equipment. Therefore, development of more energy efficient structure health monitoring (SHM) system is increasingly important for assessment of its long-term reliability. SHM has two components, one is to record history of large straining during vehicle's operation, and the other is to detect any larger damages hidden in a vehicle during or when it is at rest. This study is aimed at the first SHM issue. The concept of this new SHM is to measure the fatigue properties of piezoelectric sensors that are subjected to a set of loading. In this research, we used cantilever beam made of steel plate on which a piezoelectric thin plate is mounted. The cantilever beam is subjected to a set of known vibrations by electro-magnetic induction apparatus. Then we measured residual P-E curves of the piezo-sensor at a number of fatigue cycles. It is found that the residual polarization (Pr) of the P-E curves of fatigued piezo-sensor exhibit continuous reduction, which provides a useful data set to assess what level of loading that the cantilever beam has experienced.
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