Size effect aspects of measurement of fracture characteristics of quasibrittle material

This paper, which represents the text of an introductory report presented at Cardiff workshop in 1995, reviews the size effect from two different viewpoints: (1) the need to eliminate or minimize the effect of specimen size on the measured material fracture characteristics, and (2) the exploitation of measured size effect on the nominal strength for determining the material fracture characteristics. Three methods of fracture testing are examined in the perspective of the size effect, and the merits and weaknesses of various methods in regard to the size effect are pointed out. The parameters of all three methods can be determined by simple formulas and linear regression from measurements allowing calibration of two parameters of the size effect law.