Prefabricated crack propagation in translucent alumina ceramic sheets during flame thermal shock

Qingxian Li (1, 2) , Yuqiao Li (1, 2) , Jia Li (3) , Long Li (2) , Xiaofeng Wu (4) , Yingfeng Shao (2, 1) , Y. Charles (3) , Salma Barboura (3) , Fan Song (2, 1)

1 UCAS - University of Chinese Academy of Sciences [Beijing]
2 State Key Laboratory of Nonlinear Mechanics [Beijing]
3 LSPM - Laboratoire des Sciences des Procédés et des Matériaux
4 Beijing Institute of Structure and Environment Engineering

The prefabricated cracks propagation of ceramic under flame thermal shock was studied by real-time observation. The experimental results show that wing cracks are generated from both tips of the prefabricated crack, and the complete failure of the samples is a high-speed process. The crack propagation speed is fast at first and then gradually slows down. The maximum propagation speed of the near flame tip increases with the prefabricated crack distance to the heated surface, while an inverse trend is observed for the far flame tip. The effect of prefabricated crack angle on thermal shock crack propagation was also considered. In addition, numerical simulations based on dynamic fracture mechanics were carried out to reproduce the entire cracking process. To this end, the relation between the dynamic stress intensity factors and the crack growth speed in the speed range of 100 m/s to 2600 m/s was identified by combing experiments and numerical simulations. The simulation results and the above-mentioned relation are consistent with the experimental observations. The numerical model can faithfully reproduce the crack evolution process of the thermal shock, which is difficult to observe in an experiment due to the high speed of the cracking process.

Mots clés: Thermal shock; Crack speed; Dynamic stress intensity factor; Numerical simulation; Real-time

Domaines: Mécanique des matériaux [physics.class-ph]

Qingxian Li, Yuqiao Li, Jia Li, Long Li, Xiaofeng Wu, et al.. Prefabricated crack propagation in translucent alumina ceramic sheets during flame thermal shock. Engineering Fracture Mechanics, 2022, pp.108285. ⟨10.1016/j.engfracmech.2022.108285⟩. ⟨hal-03560222⟩