Research progress of meso-damage mechanics for ductile fracture criterion in metal forming

With the profound research in meso-damage of ductile material, meso-damage mechanics will play more and more important role in forecasting ductile fracture of metal material. Differing from macroscopic fracture mechanics, meso-damage mechanics emphasizes particularly on the influence on macroscopic fracture with the evolvement of meso-damage. The background of meso-damage mechanics was introduced, and an overview on the research and development of meso-damage mechanics was given. Then the key problems for the development of meso-damage mechanics were discussed, and the promotion of mechanism-based strain gradient plasticity theory to the development of meso-damage mechanics was proposed as well.