Figure 8
From: Micro-mechanical insights into the dynamics of crack propagation in snow fracture experiments
PFC3D parallel bond model (PBM) representation and its bonded behavior. (a) Normal mechanical parameter bonded and unbonded, where \(E_{b}\) represents the bond elastic modulus, \(\sigma_{t}\) the tensile strength, \(E_{u}\) the contact elastic modulus and \(\zeta_{u}\) the contact damping ratio. (b) Shear mechanical parameter bond and unbonded, where \(E_{b}\) represents the bond elastic modulus, \(\sigma_{s}\) the shear strength, \(E_{u}\) the contact elastic modulus, \(\nu_{b}\) the bond Poisson’s ratio, \(\nu_{u}\) the contact Poisson’s ratio and \(\mu_{u}\) the friction coefficient. To reduce the number of variables we assume \(E_{u} = E_{b} \triangleq E_{particle}\), \(\sigma_{s} = \sigma_{t} \triangleq \sigma_{bond}^{th}\) and \(\nu_{u} = \nu_{b}\). (c) Bond normal force \(N_{b}\) as a function of the normal interpenetration \(\delta_{n}\) scaled by the bond radius \(r_{b}\). (d) Bond shear force \(\left\| {S_{b} } \right\|\) as a function of tangential interpenetration \(\delta_{s}\) scaled by the bond radius \(r_{b}\). (e) Bond-bending moment \(\left\| {M_{b,1} } \right\|\) as a function of bending rotation \(\theta_{1}\) scaled by the bond radius \(r_{b}\). (f) Torsion moment \(\left\| {M_{b,2} } \right\|\) as a function of twist rotation \(\theta_{2}\) scaled by the bond radius \(r_{b}\).
