Issue 51

E. Mousavian et alii, Frattura ed Integrità Strutturale, 51 (2020) 336-355; DOI: 10.3221/IGF-ESIS.51.25 352 where the coefficient cf k for each lock can be obtained through experimental investigation on different interlocking interface geometries. (a) (b) (c) (d) Figure 17 : a) and b) Force distribution and shear resistance for a lock; c) and d) a conservative formulation for shear resistance of the interface within the convex contact model framework. Figure 18 : The orthotropic sliding resistance of an interlocking block governed by the Coulomb’s friction law and the shear resistance of the locks in two normal directions. Considering f t 1 and f t 2 two components of the tangential force f t , and q the angle between the tangential force f t and the locks, the sliding constraint of an interlocking interface as long as the locks are not cracked is (Fig. 18): 1 2 0 sin  cos  m t k i i i t n f q g b k f q f             (34) Once all the locks are fractured and separated from the main body, the interface is turned to be a conventional interface. Thus, the non-linear sliding constraint can be formulated as: