Numerical Simulation of Thermal Shock Tests of Carbon-Containing Refractories

2012 ◽  
Vol 538-541 ◽  
pp. 660-664
Author(s):  
Hui Min Liu
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Finite Element Method ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Heating Process ◽  
Stress Changes ◽  
Quenching Process ◽  
Shock Resistance ◽  
The Mathematical Model

To appraise the thermal shock resistance of carbon-containing refractories correctly, its thermal stress changes in thermal shock tests were analyzed by finite element method, and the mathematical model appraising its thermal shock fracture was built. The results show when the sample of carbon-containing refractory suffers thermal shock, the main damaged areas lie its centre during sharp heating process, but the sides during quenching process. The later is the main reason causing its damage. When appraising the thermal shock resistance of carbon-containing refractory by dip spalling method, the result matches fracture index.

scholarly journals Numerical Simulation for Thermal Shock Resistance of Thermal Protection Materials Considering Different Operating Environments

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Weiguo Li ◽  
Dingyu Li ◽  
Ruzhuan Wang ◽  
Daining Fang
Keyword(s):  
Numerical Simulation ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Thermal Protection ◽  
Thermal Environment ◽  
Full Account ◽  
Thermal Environments ◽  
Operation Conditions ◽  
Operating Environments ◽  
Shock Resistance

Based on the sensitivities of material properties to temperature and the complexity of service environment of thermal protection system on the spacecraft, ultrahigh-temperature ceramics (UHTCs), which are used as thermal protection materials, cannot simply consider thermal shock resistance (TSR) of the material its own but need to take the external constraint conditions and the thermal environment into full account. With the thermal shock numerical simulation on hafnium diboride (HfB2), a detailed study of the effects of the different external constraints and thermal environments on the TSR of UHTCs had been made. The influences of different initial temperatures, constraint strengths, and temperature change rates on the TSR of UHTCs are discussed. This study can provide a more intuitively visual understanding of the evolution of the TSR of UHTCs during actual operation conditions.

Carbide Particle-Reinforced Tungsten Composites in Extreme Hazard Environments

2013 ◽  
pp. 509-532
Author(s):  
Guiming Song ◽  
Yujin Wang ◽  
Yu Zhou
Keyword(s):  
Finite Element Method ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Early Stage ◽  
Peripheral Zone ◽  
Damage Mode ◽  
Ablation Resistance ◽  
Tic Particle ◽  
Shock Resistance ◽  
Disk Sample

The ablation as well as the associated thermal shock resistance of tungsten composites reinforced by TiC and ZrC particles is investigated with an oxyacetylene equipment. 30TiC/W (30TiC stands for 30 vol. % TiC particle content in tungsten, the same below) and 40TiC/W fail to withstand the thermal shock of 2000ºC/s during heating. In contrast, 30ZrC/W and 40ZrC/W withstand the thermal shock. Additionally, ZrC/W composites exhibit better ablation resistance than TiC/W composites. The thermal stress fields of the composite at both macro-/micro-scales induced by thermal shock at the early stage of the ablation are analyzed using finite element method. The calculated results of the damage mode of the composites show that crack initiates at the disk sample peripheral zone and then propagates to the sample center, which is consistent with the experimental observation.

scholarly journals Numerical Simulation for Thermal Shock Resistance of Ultra-High Temperature Ceramics Considering the Effects of Initial Stress Field

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Weiguo Li ◽  
Tianbao Cheng ◽  
Dingyu Li ◽  
Daining Fang
Keyword(s):  
Numerical Simulation ◽  
High Temperature ◽  
Stress Field ◽  
Thermal Shock ◽  
Cooling Rate ◽  
Thermal Shock Resistance ◽  
Initial Temperature ◽  
Ultra High Temperature Ceramics ◽  
External Constraint ◽  
Shock Resistance

Taking the hafnium diboride ceramic as an example, the effects of heating rate, cooling rate, thermal shock initial temperature, and external constraint on the thermal shock resistance (TSR) of ultra-high temperature ceramics (UHTCs) were studied through numerical simulation in this paper. The results show that the external constraint has an approximately linear influence on the critical rupture temperature difference of UHTCs. The external constraint prepares a compressive stress field in the structure because of the predefined temperature field, and this compressive stress field relieves the tension stress in the structure when it is cooled down and then it improves the TSR of UHTCs. As the thermal shock initial temperature, a danger heating rate (or cooling rate) exists where the critical temperature difference is the lowest.

Numerical Simulation for Thermal Shock Resistance of Thermal Protection Materials under Temperature Rising

2011 ◽  
Vol 197-198 ◽  
pp. 1509-1514 ◽  
Author(s):  
Wei Guo Li ◽  
Ding Yu Li ◽  
Chao Wang ◽  
Dai Ning Fang
Keyword(s):  
Numerical Simulation ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Thermal Protection ◽  
Thermal Environment ◽  
Ultra High Temperature Ceramics ◽  
Service Environment ◽  
External Constraint ◽  
Visual Understanding ◽  
Shock Resistance

Due to the complexity of service environment of thermal protection system on the aerocraft, the thermal shock resistance (TSR) of ultra-high-temperature ceramics (UHTCs), which are used as thermal protection materials, is no longer the material itself’s. Based on the restrictions of current experiments and the lack of theories, hafnium diboride (HfB2) is used to study the effects of the external constraint conditions and different thermal environment on the TSR of the UHTC in detail. The effects of different initial temperature, different external constraint conditions, and temperature rising rate on the TSR of the UHTCs through numerical simulation are discussed in detail in this study. This study can provide a more intuitively visual understanding of the evolution of the TSR of UHTCs during actual causative conditions.

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