Numerical Analysis of Thermal Shock Cracking Behaviors of Ceramics Based on the Force-Heat Equivalence Energy Density Principle

Dingyu Li,Zhongshuai Liu,Yong Pang,Shiwei Chen,Tao Lu

doi:10.3389/fmats.2021.825327

Abstract

Thermal shock is one of the main causes for the fracture of ceramic materials due to their inherent brittleness. Aiming to explore the mechanism of thermal shock cracking behavior of ceramics under different thermal shock conditions, a novel temperature-dependent failure criterion of thermal shock fracture of the ceramic materials was deduced based on the force-heat equivalence energy density principle. Combining this failure criterion and the finite element method, the thermal shock cracking behaviors of the thin circular and rectangular ceramic slabs under different thermal shock initial temperature were simulated. Results show that the morphology, periodicity, hierarchy, and number of thermal shock cracks obtained by numerical simulation are in good agreement with the experimental results. These essential characteristics verify the validity of the temperature-dependent failure criterion for thermal shock fracture. Furthermore, the strain energy of tension produced by thermal shock is proved to be the dominated mechanism for thermal shock-induced fracture.

Highlights

Because of the good thermophysical properties and chemical stability, such as high melting point and corrosion resistance, ceramic materials are widely used in high-temperature fields such as aerospace technology, metallurgy, and machinery (Cui et al, 2021a; Wang et al, 2021)
As the initial temperature increases, the number of cracks in the model increases, and the crack spacing gradually decreases. This indicates that the thermal shock initial temperature is one of the main factors affecting the crack spacing
This paper derives a new temperature-dependent failure criterion based on the force-heat equivalence energy density principle

Summary

INTRODUCTION

Because of the good thermophysical properties and chemical stability, such as high melting point and corrosion resistance, ceramic materials are widely used in high-temperature fields such as aerospace technology, metallurgy, and machinery (Cui et al, 2021a; Wang et al, 2021). The current experimental methods cannot real-time capture the crack nucleation and propagation process of thermal shock and cannot effectively uncover the corresponding mechanisms in ceramics This limits the development of ceramic materials. The numerical simulation of ceramic materials is carried out by using the finite element software ABAQUS combining with the subroutine USDFLD which embedded the proposing temperature-dependent failure criterion in Temperature-Dependent Failure Criterion of Thermal Shock Based on the Force-Heat Equivalence Energy Density Principle. The mechanical properties of the ceramics showed brittle behavior in the studied temperature range, the thermal shock crack growth rate is fast, and when the failure energy density reached the critical value, the material is destroyed, that is, in the process of model calculation, the material only exists in two states before- and after- fracture. The initial ambient temperature is 20°C, and the heat transfer coefficient is ts 65 kW/(m2 K)

RESULTS AND DISCUSSION

CONCLUSION

DATA AVAILABILITY STATEMENT