New analysis of holophotoelastic patterns and their application

This paper shows that by the use of a new type of diffuser it is possible in photo-holoelasticimetry, without any addition of optical elements or particular preparation of the specimen, to record simultaneously but separately fringe patterns respectively related to the sum and the difference of the principal stresses. The value of intensity of the interfering light reaching the hologram plate is established and hence the equations of the recorded pseudoisopachic fringe patterns are given. Used successfully for the study of particular static problems, where numerical methods are very difficult or impossible, the present interferometer is also suited for dynamic problems.