Figure 4

(a) Characterization of sensor gauge factor with the crack opening. (b–f) Optical microscope images of crack width measurement of five samples at the crack intensity of 25% below the CIS level in increasing order.

(a) Characterization of sensor gauge factor with the crack opening. (b–f) Optical microscope images of crack width measurement of five samples at the crack intensity of 25% below the CIS level in increasing order.