Abstract
In quantitative measurement of strain by brittle coating, it is very important for explanation of reliability of this method to investigate the error of measurement. As the previous paper shows, the mean value of distances of cracks which appeared in the coating on the specimen subjected to uniform tensile strain decreases linearly with the increment of strain. However, the cracks do not appear in equidistant, but are scattered in some range. This scattering brings error for quantitative measurement of strain. Then, in measurement of the mean value of crack distances, investigated the relation between the measured number of crack distances and the reliability. As a result of this investigation, we may adopt the various method to elevate the accuracy of the strain determination.
