| 摘要 |
PURPOSE:To measure the resisting property against thermal shock suppressing the mixing-in of the noise due to abnormal high temperature by directing laser light in pulses and detecting acoustic emission signals only during the laser output is stopped. CONSTITUTION:A gate circuit 7 is provided between a laser light output controller 3 and an acoustic emission (AE) measurement device 6. The gate 7 stops measurement of AE signal while a laser light is being applied, and it makes measurement only when the output of the laser light is stopped. The laser light is applied in pulses to actuate the gate circuit 7, and when the AE signal is detected while the output is stopped, the mixing-in of noises accompanying cracks as in the figure can be stopped and only AE signal due to cracks is detected. In the curves, it is known that the material B is continuous without stepped material changes and it has a resistance to the advance of crack better than that of the material A. In this way the resisting property against thermal shock can be measured with high accuracy. |
