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Non-pneumatic tires have been developed and being investigated, but not much prevalent. Many design studies are yet needed from the viewpoint of material, pattern, and structures. No systematic research for such important design issues have been reported in the literature. In this paper, as the first important step of design, topology optimization was utilized to determine optimal topological patterns of non-pneumatic tires, with the goal of matching the static stiffness of the current pneumatic tires. Under the optimization formulation with weighted compliance and a volume constraint, several different patterns were obtained depending on the number of patterns, volume fraction, and weighting factors. Among them, three representative patterns were chosen and analyzed for their possible applications under specific working condition. This paper proposes a systematic and efficient tool for designing the topological patterns of non-pneumatic tires.

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The refractory lined components could be damaged during operation due to various causes such as thermal expansion and contraction from changes of the temperature in service fluids, vibration caused by internal flow, or improper refractory construction. The damaged refractory causes thermal hot spot because a hot service fluid contacts to the inside surface of the component directly and this situation leads temperature increases in the skin of the component. This temperature increases from thermal hot spot does not causes immediate failure of the component, but creep phenomenon can cause structural rupture in the long term. As one of the countermeasures against thermal hot spot, the steam cooling is used as a field practice of maintenance works to reduce elevated temperature by spraying steam onto the area of thermal hot spot. However, when steam cooling is applied, it is designed and installed based on experiences without performing proper engineering. After steam cooling is applied, it is observed that thermal hot spot is locally cooled only in the area where the steam touches, which also raises concerns about unexpected damage due to local temperature gradient from localized cooling. This paper provides the evaluation of structural integrity of an actual case of thermal hot spot subjected to steam cooling in the FCC unit and discusses the appropriate steam cooling method as a countermeasure for thermal hot spot to ensure more effective structural integrity.