Dislocation based Plasticity

P1 - Dislocation based Gradient Plasticity Theory

The applicability of classical continuum plasticity theories to microscale plasticity is limited by the processes governing the plastic deformation, and the associated evolution of the microstructure in crystalline solids. Predominant mechanisms include the motion and interactions of dislocations. These processes become directly 'visible' on the system scale. The formal framework of classical constitutive plasticity can not account for them and the associated internal length and time scales. A solid foundation for understanding the properties of dislocations and the dynamics of dislocation systems has been created by research in the physics and materials science communities. The detailed physical knowledge needs to be transferred into a corresponding modelling and simulation methodology that allows for computational efficiency and applicability.

 

In order to achieve this goal in P1, three important supporting factors can be considered within the reseach group FOR1650. Discrete dislocation dynamics simulations constitute a powerful tool for developing advanced continuum plasticity models. The physically detailed discrete simulations can provide a reference that allows to carefully assess and control the consequences of coarse-graining and averaging operations.

 

These are necessary for the formulation of continuum models. In addition, 3D continuum dislocation dynamics (CDD) can be directly considered as a coarse-grained, density based representation of the 3D dynamics of curved and interacting dislocation lines. Both approaches serve as input for the development of a physically sound and numerically efficient gradient plasticity theory for finite strains that allows to simulate large microspecimen deformations in a numerically efficient manner. Furthermore, the theory to be developed is validated with experiments.

 

 

This project consists of five milestones:
  • Classification of the information about the microstructure into essential and incidental information regarding the prediction of a given deformation process.
  • Formulation of an adequate mathematical framework that incorporates both the essential microstructural variables, and their evolution within a continuum theory taking into account DDD and CDD results.
  • Computationally efficient implementation of the model.
  • Validation of the theory by means of experimental data.
  • Further development of the model in collaboration considering DDD and CDD simulations.

Members :

Prof. Dr.-Ing. Thomas Böhlke , Institute for Engineering Mechanics, KIT

Dipl.-Ing. Eric Bayerschen, Institute for Engineering Mechanics, KIT

M.Sc. Andreas Prahs, Institute for Engineering Mechanics, KIT