FRACTURE ENERGY DETERMINATION OF QUASI-BRITTLE MATERIALS

A simple method is proposed for determination of fracture energy of ma terials exhibiting quasi-brittle behavior during mode I cracking. A se ries of graphs showing the relationship between the nondimensional pea k load and the nondimensional beam size are generated for a three-poin t beam configuration using a new and computationally efficient finite- element program. The method only requires the measurement of the peak load of a single-size beam specimen. It is preferred that the beam spe cimens have a small preexisting notch to ensure mode I cracking in a t hree-point bending test. The other required material properties for th e use of nondimensionalized graphs include Young's modulus and tensile strength. Since the three-point bending test can be easily carried ou t in the laboratory, the proposed method offers a practical, yet exped ient, way of characterizing the nonlinear fracture properties of mater ials that follow the linear stress-separation behavior in the process zone.