Comparison between grating rosette and strain gage rosette in hole-drilling combined systems

Hole-drilling method is a most common technique for measuring residual stresses in various materials and structures, in which the strain gage rosette is usually used to obtain the strain distributions caused by deformation. To avoid disadvantages in the strain gage system, different strain measure methods have been proposed in the previous references. In this paper, an optical technique called as grating rosette and Moiré interferometry is presented and compared with the strain gage one. It is found that higher measure accuracy can be achieved as the hole drilling is combined with the new optical technique instead of the strain gage rosette.