Scalar damage model for concrete without explicit evolution law

TL;DR

This paper introduces a scalar damage model for concrete that avoids explicit evolution laws by directly deriving damage from the projection algorithm, simplifying the modeling process and improving computational efficiency.

Contribution

It proposes a novel scalar damage model that eliminates the need for an explicit evolution law and uses a polynomial loading surface for better continuity and simplicity.

Findings

Model accurately predicts mixed-mode fracture behavior.

Performance depends on the chosen stress degradation law.

Polynomial loading surface ensures C1 continuity.

Abstract

Based on the fact that for an isotropic material model the elastic predictor and the projected stress tensors have the same eigenvectors, it is shown that the scalar damage can be obtained directly from the projection algorithm. This eliminates the difficulty of a proper definition of equivalent strain which serves as a driving force for evolution of damage in concrete. Moreover, if eigenvectors are known it is not more nec-essary to use invariants of the stress tensor for the formulation of loading surface. In the present model the loading surface is represented in the polynomial form. This has two advantages: (i) it automatically fulfils C1 continuity and (ii) plane stress formulation is achieved by simply setting the third stress to zero. The perform-ance of the model is illustrated on example of a mixed-mode fracture of concrete. It is shown that for the pre-sent example the model prediction strongly depends on the choice of the stress degradation law.