Crack Analysis in Structural Concrete

Chapter 7. Mixed-Mode Fracture

7.1. Introduction

In establishing the fictitious crack model (FCM) for analyzing the mode-I type of cracks in concrete, Hillerborg et al. (1976) had also indicated the possibility of applying the concept to model other types of fracture, such as the shear fracture of the mode-II or mode-III type. Much effort has since been made to extend the fictitious crack model to mixed-mode fracture because most practical fracture problems in concrete are mixed-mode, involving modes I and II. In modeling the shear transfer mechanism in the fracture process zone (FPZ), numerical studies in this category often rely on interface elements: The stiffnesses of interface connections in the normal and tangential directions are assumed ...