抄録
A new method for measuring stress-live, residual or that due to dead load-on the surface of metallic structures is described.
The method is based essentially on the elastic redistribution caused by removal of a small portion of the concerned part of structure, that is the stress relief method in combination with the photoelastic coating method.
A thin sheet of appropriate photoelastic material is cemented on the metal surface, and a small circular hole (for instance, 2.0mm in diameter) is drilled through the film into the metal to a certain depth, then the photoelastic stress pattern is visualized by means of a reflection type polariscope.
Both the magnitudes and the directions of two principal stresses can be easily obtained by counting the photoelastic coloured or monochromatic fringes.
However small the hole is drilled, the sensitivity of the method is not essentially Towered. Therefore this method is considered most non-destructive among the known mechanical methods of measuring residual stresses.
The principle and technique of the method together with the sensitivity and the accuracy are described.
