Acoustic source modeling of crack initiation using the phase-field method

Abstract

Dynamic crack propagation is a major source of elastic wave radiation in brittle materials and forms the physical basis of acoustic emission monitoring. In this work, a dynamic phase-field fracture model is employed to investigate the generation of acoustic-like signals during intermittent crack growth in a pre-stressed tapered double cantilever beam configuration. The fracture process is described using a linear phase-field formulation, while wave propagation is resolved through an implicit dynamic finite element scheme without damping. A staggered solution strategy is adopted to couple mechanical equilibrium and damage evolution. Numerical results show that rapid crack advance generates oscillatory strain signals at a remote sensor location, with signal amplitude and complexity increasing with crack velocity. The simulations further indicate the existence of a velocity threshold below which fracture produces weak acoustic activity. These findings highlight the strong coupling between fracture dynamics and wave propagation and demonstrate the potential of phase-field modeling as a quantitative tool for interpreting acoustic emission measurements in brittle materials.