Impact of damage on the effective properties of network materials and on bulk and surface wave propagation characteristics
Abstract
We analyze in this contribution the propagation of bulk and Rayleigh surface waves in periodic architectured materials undergoing internal damage. An elastic damageable continuum-based model is developed in the framework of the thermodynamics of irreversible processes, whereby the displacement experiences a jump across the faces of the propagating crack. The crack propagation involves an enhancement of the displacement field associated with embedded discontinuities, which remain localized within each (triangular type) finite element. The displacement discontinuity is regulated by the traction separation behavior described by an exponential cohesive model with damage hardening followed by softening. The effective mechanical properties of the overall network are evaluated versus the increasing damage. The phase velocities for the longitudinal and transverse modes are then computed continuously versus the amount of damage, considering successively the situations of symmetrically and unsymmetrically distributed damage occurrence and propagation. Simulation results show that although the crack pattern is different in these two situations, it has no impact on the evolution of the effective moduli versus global damage. The phase velocities computed based on the effective moduli decrease as damage propagates within the network; thus, it is an indicator of the amount of global damage.