Deformation measurement during powder compaction by a scanning-moiré method

The mechanical behavior of powders during compaction has been studied in previous papers. It has been shown that a moiré method may be used to determine the resulting strain distribution. Some difficulties were encountered, however, in the method used. In the present paper, therefore, an image-processing system employing a personal computer to analyze the moiré pattern is introduced. Many strain distributions obtained in this way from moiré-fringe patterns are presented. Further, using this image-processing system, a scanning-moiré technique is developed in which the master grating is replaced by the scanning lines of a television camera. The use of image processing in conjunction with the mismatch technique allows measurement of both small and large strains from one image picture.