Effect of Initial Crack Length of C(T) Specimen on Crack Propagation Measurement by Dc Potential Drop Method

The compact tensile specimens ( C(T) specimens) are commonly used in crack propagation tests. The DC potential drop method is an important method for measuring crack length in crack propagation tests. To investigate the influence of the initial crack length of the C( T) specimen on the calibration curve in practice, the variation law of the potential field distribution of the compact tensile specimen with the crack propagation has been studied. The measurement features in different initial crack lengths and different current injection positions were quantitatively analyzed. The results show that the initial crack length has a significant effect on the sensitivity of the signal and the linearity of the calibration curve. The sensitivity can be improved by increasing the initial crack length, while the linearity decrease.