Crack-growth detection using a surface-mounted piezotransducer array

This paper reports on an experimental program aimed at assessing the feasibility of monitoring crack growth by means of a surface-mounted piezotransducer array. The host structure is interrogated using lamb-waves generated and sensed by elements in the array. An example is described involving a uniaxial edge-notched specimen subject to cyclic loading where the array is shown to be capable of detecting on a sustained basis crack growth increments of less than 0.1 mm. Although the piezoceramic elements were exposed to cyclic stress there was no measurable indication of element degradation, indicating good fatigue durability properties under the loading regime considered. Experimental results are also shown that demonstrate a strong crack-state dependence, highlighting the need for care when interpreting signals from the piezotransducers.