Abstract:
It is well known that all important nonlinear fracture models can capture adequately the structural size effect over the useful range of applicability. The size-effect study of various fracture parameters obtained from two-parameter fracture model, size-effect model, effective crack model, double-K fracture model, and double-G fracture model with respect to fictitious crack model is presented in this chapter. To this end, different fracture parameters from size-effect model, effective crack model, double-K fracture model, and double-G fracture model are evaluated using standard procedures for which the input data are obtained from fictitious crack model for three-point bending test. In addition, the fracture parameters of two-parameter fracture model are obtained using the mathematical coefficients available in literature. From the study it is observed that the fracture parameters obtained from various nonlinear fracture models including the double-K and double-G fracture parameters are influenced by the specimen size. These fracture parameters maintain some definite interrelationship depending upon the specimen size and the relative size of initial notch length.