CONNECTION BETWEEN STRENGTH REDUCTION, ELECTRIC RESISTANCE AND ELECTRO-MECHANICAL IMPEDANCE IN MATERIALS WITH FATIGUE DAMAGE

摘要

In this paper we report experimental results on the connection between the strength reduction due to accumulated damage in elastic electrically conductive material, resistance variation across the damaged specimen and changes in electro-mechanical impedance (EMI) response. We compare behavior of a cyclically loaded specimen (44,000 loading cycles with the stress amplitude near 0.5 of the yield stress) and intact one (nonloaded). Electro-mechanical impedance testing of the specimens was carried out and the electrical resistances of different parts of the specimens were measured. Finally, both the specimens were tested for ultimate strength under uniaxial tension. We observed qualitative correlation between changes in EMI response, electrical resistance and strength reduction in damaged specimen.