High-cycle fatigue damage measurement based on electrical resistance change considering variable electrical resistivity and uneven damage

The definition of damage variable based on electrical resistance changes was investigated. Under the hypothesis of a current-conducting section equivalent to a load-bearing section, the fatigue damage evolution may be represented effectively. For rotary bending high-cycle fatigue test, the formula of fatigue damage measurement considering uneven damage distribution and variable electrical resistivity was developed, which is the hypergeometric function. The analysis shows that in the range of damage 0–0.6, the formula is approximate to damage measurement based on electrical resistance changes due to uniform damage and constant electrical resistivity. High-cycle fatigue damage measurement for common structural steels was performed, and the comparison of experimental data with the predictions shows agreement.