Symmetric-Galerkin boundary element analysis of the dynamic T-stress for the interaction of a crack with an auxetic inclusion

• We investigate the auxeticity effect on the stress intensity factors and the T-stress.
• The Laplace symmetric-Galerkin boundary element method is employed in this study.
• The auxeticity has virtually no effect on the stress intensity factors.
• The influence of the auxeticity on the T-stress is noticeable.
• Two-parameter criteria should be used to model crack growth in auxetic composites.

In this work, the symmetric-Galerkin boundary element method (SGBEM) for 2-D elastodynamics in the Laplace-space frequency domain (Laplace domain) is employed to study the dynamic stress intensity factors (DSIFs) and the dynamic T-stress (DTS) during the interaction between a crack and an auxetic inclusion under impact loading conditions. It is found that, while the auxeticity has virtually no effect on the DSIFs, its influence on the DTS is noticeable. This finding is particularly important as it implies the imperative need of fracture criteria based on both the DSIFs and DTS for predicting crack growth in composite materials with auxetic phases.