Damage-Elasto-Plastic Spring for Micro-Structured Materials Derived With a Hemivariational Approach: Applied to Ultra High Performance Concrete (UHPC)

We illustrate a hemivariational approach for modeling a particular rate-independent damage-elasto-plastic spring. The aim is to consider a simple yet practically important case, i.e. a brittle material such as the Ultra High Performance Concrete UHPC. The hemivariational principle is posed in the form of an inequality associated to the variation and to the increment of the action, that is properly defined and it is interpreted as a principle of maximum energy dissipation rate. Such a spring model is also characterized by tension-compression asymmetry not only in terms of elastic reaction stiffness but also in terms of damage and plastic behavior. Examples are also calculated. They show and demonstrate the model performance. It is worth to mention that from one point of view the spring model is easy to compute. From another point of view, it can be implemented into the granular micromechanics approach for describing the 3D behavior of UHPC.