Aplicação da técnica da emissão acústica no monitoramento do dano em materiais heterogêneos

Abstract

The use of the Acoustic Emission Technique (AET) has proven to be a useful and assertive tool in damage monitoring and failure prediction in small and large structures or equipment, within civil and mechanical engineering. The technique is based on capturing elastic waves emitted at the time of formation or development of a discontinuity such as cracks, for example. In the present work, AET is applied to data obtained from simulations of a Peridynamic model, with the aim of analyzing the progression of damage to heterogeneous materials. The model results are compared with experimental data from an expanded polystyrene beam and a rock beam, both in a three-point bending test. Force, displacement and acoustic emission (AE) data are available for comparison. Behavior patterns of AE activity were identified and events characterized as monitoring indices such as b-value and c-value were evaluated. Furthermore, the identification of the predominant failure mode was analyzed through the AE. The peridynamic theory was recently developed as a theory of nonlocal analysis capable of defining structures with active or non-active discontinuities and with more general applicability than classical theories, such as the finite element method. The comparison with experimental data shows that peridynamics is effective in simulating the behavior of heterogeneous materials, evaluated through force-displacement or stress-strain curves. From the AET point of view, the monitoring indices applied to experimental and numerical data had a good response. Thus, peridynamics presents itself as a good tool to help in the development of new monitoring indices and also in the planning of AE tests. Keywords: Acoustic Emission, Peridynamics, discontinuities, heterogeneous materials