This study investigates the risks of non-conservative piping design according to ASME B31.1 for hightemperature piping subjected to long-term operation at high temperature in a creep regime based on a sensitivity anal...This study investigates the risks of non-conservative piping design according to ASME B31.1 for hightemperature piping subjected to long-term operation at high temperature in a creep regime based on a sensitivity analysis of the hold time. Design evaluations of hightemperature piping were conducted over a range of hold times in the creep regime according to ASME B31.1,which implicitly considers the creep effects, and the French high-temperature design code of the RCC-MRx, which explicitly considers the creep effects. Conservatisms were quantified among the codes in terms of the hold times. In the case of B31.1, the design evaluation results do not change depending on the hold time at high temperature,whereas in the case of RCC-MRx, they do. It was shown that the design limits of RCC-MRx were exceeded when the hold time exceeded certain values, whereas those of B31.1 were satisfied regardless of the hold times. Thus, the design evaluations according to B31.1 did not consistently yield conservative results and might lead to non-conservative results in the case of long-term operations in the creep range.展开更多
均匀的螺栓载荷对法兰密封性能有极为重要的意义,由于螺栓间存在弹性交互作用,采用扭矩增量控制法按一定加载顺序加载才能降低螺栓载荷离散程度。试验研究了ASME PCC-1传统的加载方法(LEGACY方法)和JIS B 2251加载方法在DN100法兰8螺栓...均匀的螺栓载荷对法兰密封性能有极为重要的意义,由于螺栓间存在弹性交互作用,采用扭矩增量控制法按一定加载顺序加载才能降低螺栓载荷离散程度。试验研究了ASME PCC-1传统的加载方法(LEGACY方法)和JIS B 2251加载方法在DN100法兰8螺栓结构中的加载规律,以及载荷渐增顺次螺栓加载方法。采用应变片和应变仪实时监测螺栓载荷,采用力矩扳手加载。结果表明,ASME传统加载方法较为繁琐,JIS B 2251加载方法效率高且不易出错;以扭矩增量控制法顺次加载也能获得均匀的螺栓载荷;在保证充足预紧轮次的情况下,加载方式对最终螺栓载荷的离散程度影响不大,最后以目标载荷顺次加载几轮非常有必要。展开更多
基金supported by National Research Foundation Grants(NRF-2012M2A8A2025635 and NRF-2017K1A3A7A03086464)funded by the Korean Government(Ministry of Science,ICT and Future Planning)
文摘This study investigates the risks of non-conservative piping design according to ASME B31.1 for hightemperature piping subjected to long-term operation at high temperature in a creep regime based on a sensitivity analysis of the hold time. Design evaluations of hightemperature piping were conducted over a range of hold times in the creep regime according to ASME B31.1,which implicitly considers the creep effects, and the French high-temperature design code of the RCC-MRx, which explicitly considers the creep effects. Conservatisms were quantified among the codes in terms of the hold times. In the case of B31.1, the design evaluation results do not change depending on the hold time at high temperature,whereas in the case of RCC-MRx, they do. It was shown that the design limits of RCC-MRx were exceeded when the hold time exceeded certain values, whereas those of B31.1 were satisfied regardless of the hold times. Thus, the design evaluations according to B31.1 did not consistently yield conservative results and might lead to non-conservative results in the case of long-term operations in the creep range.
文摘均匀的螺栓载荷对法兰密封性能有极为重要的意义,由于螺栓间存在弹性交互作用,采用扭矩增量控制法按一定加载顺序加载才能降低螺栓载荷离散程度。试验研究了ASME PCC-1传统的加载方法(LEGACY方法)和JIS B 2251加载方法在DN100法兰8螺栓结构中的加载规律,以及载荷渐增顺次螺栓加载方法。采用应变片和应变仪实时监测螺栓载荷,采用力矩扳手加载。结果表明,ASME传统加载方法较为繁琐,JIS B 2251加载方法效率高且不易出错;以扭矩增量控制法顺次加载也能获得均匀的螺栓载荷;在保证充足预紧轮次的情况下,加载方式对最终螺栓载荷的离散程度影响不大,最后以目标载荷顺次加载几轮非常有必要。
