A modified conjugated bond-based peridynamic analysis for impact failure of concrete gravity dam

Description of the impact damage of dams subjected to projectile penetration objectively is a significant but difficult issue. To take the advantages of bond-based peridynamics (BB PD) in analyzing multiple crack growth and fragmentation, a modified conjugated BB PD model with two micro-moduli is established for analyzing the quasi-static deformation and the projectile impact damage of a typical concrete gravity dam. The nonlocal interaction force in the conjugated BB PD is not only related to the relative normal stretch of a bond, but also related to a series of relative rotation angle of a pair of conjugated bonds. This model can be regarded as considering the tensile spring and the rotation spring together, so that it can break through the fixed Poisson's ratio limitation of the original BB PD model due to the central pairwise interaction. Furthermore, compared with the original conjugated BB PD model, the definitions of tangent bond force and rotation strain energy density are distinctly different, which will not varied with different geometry discretization; also an attenuation kernel function related to the bond length is incorporated to reflect the decreasing long-range force with the increasing distance between material points. Finally, the failure analysis of a dam subjected to high-velocity projectile impacting at the center of dam crest demonstrates the effectiveness of the PD method for simulating the projectile impact failure.