The result of the study is the base of some procedure of fatigue crack detecting by the EMI method without baseline use.

But the effect to the PZT resistance is more complex and more significant. It is established that the FCOC effect to magnitude and reactance of EMI mainly associated with variation of the capacitance of PZT under mechanical load. The EMI was measured in the frequency range of 20-40 kHz. Each sample was loaded by tensile axial static load from zero to 12 kN and the EMI measurement after eacn 2 kN incrementat of load. Other sample after fatigue testing had central fatigue crack of 40 mm length (including a 4 mm central hole for the initiation of a fatigue crack. Experimental study performed using the flat samples of aluminum alloy. The purpose of this article is to evaluate this effect to the electromechanical impedance (EMI) of the system 'piezoelectric transducer / host structure.

Earlier the effect of fatigue crack opening/closing (FCOC) to ultrasound guided wave propagation was investigated.