抄録
The strain gage called "K-gage" was developed to measure the stress intensity factor (K) applied to a cracked member in structure. This gage measures the strain distribution around the crack tip and the measured strain is transformed into stress intensity factor. The accuracy of the measurement of the stress intensity factor is within ±10 percent compared to the exact value. Using this gage, the stress intensity factor can be measured directly under service conditions for an actual structure. It is expected to be a useful tool for the prediction of fatigue crack propagation life.
