For design with fibre reinforced concrete, engineers require a simple yet reliable approach that explains and models with sufficient accuracy material behaviour under load. In previous research, separate models have been developed to describe both Modes I and II fracture.…
For design with fibre reinforced concrete, engineers require a simple yet reliable approach that explains and models with sufficient accuracy material behaviour under load. In previous research, separate models have been developed to describe both Modes I and II fracture. This paper reviews the mechanical ba- sis of these models and a unified model is developed using the variable engagement model (VEM) approach. The model is developed by integrating the behaviour of single, randomly oriented, fibres over 3D space and, based on quantifiable material and mix parameters, is shown to be capable of capturing the stress versus crack opening/sliding displacement response for steel-fibre reinforced composites in both the pre- and post-peak stages for Modes I and II fracture. In addition to describing both Modes I and II fracture in a rational way, it is hypothesised that the approach is valid for mixed mode fracture.