Studying the influence of inclusion characteristics on the   characteristic length involved in quasi-brittle materials using the lattice   element method
  Unlike nonlocal models, there is no need to introduce an internal length in the constitutive law for lattice model at the mesoscopic scale. Actually, the internal length is not explicitly introduced but rather governed by the mesostructure characteristics themselves. The influence of the mesostructure on the width of the fracture process zone which is assumed to be correlated to the characteristic length of the homogenized quasi-brittle material is studied. The influence of the ligament size (a structural parameter) is also investigated. This analysis provides recommendations/warnings when extracting an internal length required for nonlocal damage models from the material mesostructure 
Huu Phuoc Bui, Vincent Richefeu and Fr\'ed\'eric Dufour
cs.CE