A method to generate damage functions for quasi-brittle solids

In continuum damage mechanics theories, damage functions are identified based on experimental records. These functions also serve as strain hardening-softening,functions similar to the conventional plasticity formulations. In a class of damage theories described in this paper it will be shown that if care is not taken, internal contradictions will arise as manifested by a snapback in the strain-stress space. This paper establishes a formal method by which different damage functions can consistently be developed leading to no snap-back in the solution.