Evolution of damage-induced nonlinearity in proximity of discontinuities in concrete

Understanding the mechanisms and modalities of damage progression close to discontinuities in solids, such as joints, is of great importance for applications in different fields. The interaction between damage and elasticity causes a nonlinear elastic response of the sample to a stress excitation (e.g. in the ultrasonic frequency range). Extracting physical or mechanical information on the sample properties from recorded ultrasonic signals requires a realistic model and an efficient detection method, as it will be discussed in this paper. We study here the successive phases that concrete samples with discontinuities enter by progressively increase the applied external load. Considerations on the mechanisms of damage progression are derived from experimental data using a Preisach–Mayergoyz space approach, developed in order to capture all the observed behaviors.