Abstract
The previously developed microplane concrete model is improved to expand its applicability and reformulated as the enhanced microplane concrete model serving as a more general constitutive law. One of the main improvements is to take into account the resolved lateral stress in normal compression response on a microplane as well as the resolved lateral strain. Another main improvement is to adopt a model for the transition from brittle to ductile fracture for the shear response on a microplane at increasing resolved normal compression stress. These improvements endow the model with the capability to describe complicated interaction between microplanes through the macroscopic stress tensor. Similar effects are taken into account in the microplane hysteresis rule using the concepts of back-stress and objective-stress.
