Thermal shock fracture analysis of auxetic honeycomb structure based on Dual-Phase-Lagging model

Thermal shock fracture of auxetic honeycomb structures (HSs) is investigated using the Dual-Phase-Lagging (DPL) heat conduction model. The auxetic honeycomb is treated as a homogenized orthotropic continuum, and a one-dimensional thermal shock problem containing a Mode-I crack is formulated. The temperature field is obtained using the Laplace transform and numerical inversion, while the thermal stress and stress intensity factors (SIFs) are derived using displacement functions and the collocation method. The present temperature solution is verified against published DPL results, with a maximum relative deviation below 1%. The effects of the relaxation ratio, crack length, crack position, and honeycomb angle are then analyzed by comparing the DPL, Cattaneo-Vernotte (CV), and Fourier models. The results show that when the phase-lag times are comparable to the characteristic thermal loading time, the DPL model predicts more pronounced transient temperature, thermal stress and SIF than the CV and Fourier models. Within the present one-dimensional homogenized linear elastic fracture mechanics framework, the selected auxetic honeycomb geometry reduces the effective maximum thermal stress and SIF compared with the corresponding conventional geometry. These findings highlight the importance of DPL modeling in short-time non-Fourier regimes and suggest the potential of auxetic HSs for thermo-mechanical protection applications.