Photograting 法による実験的ひずみ解析方法

Abstract

Previously, the authors reported results obtained through the usual method of experimental strain analysis by photograting, applying the method to two-dimensional problems (using experimental values of interference fringe spacing and inclination), and also suggested a new method of experimental strain analysis by photograting. In the new method, the inclinations of two interference fringe patterns with the reference axis ∅+ and ∅-, where the master screen axis makes the angle +θ and -θ respectively with the reference axis, are used.In this paper, two methods of experimental strain analysis by photograting are presented and the accuracy of strain measurement by the new method is described and discussed.It has been clarified that the new method makes strain measurement easier and helps to improve the accuracy of measurement. It was also concluded that the angle θ should be 2° for strains less than 1% and 3° for about 1% strain and with increasing strain greater θ's must be adopted to get high accuracy.