Probabilistic Risk Assessment of Piping Systems

• Main Authors: Sturm Chang, 張順庭
• Other Authors: Wen-Fang Wu
• Format: Others
• Language: zh-TW
• Published: 1993
• Online Access: http://ndltd.ncl.edu.tw/handle/95712123814845210652

碩士 === 國立臺灣大學 === 機械工程研究所 === 81 === The objective of the present study is to investigate the failure mechanisms of piping systems and to develop a probabilistic fracture mechanics model for the reliability analysis of piping systems. In the failure analysis, it is concluded through the present study that major causes for the failure of piping systems include intergranular stress corrosion crack, thermal fatigue crack, vibratory fatigue, water hammer, erosion and cavitation. All these causes are closely related to the defect sizes, loading conditions and material properties of the structures. Therefore, in the probabilistic fracture mechanics approach, these factors are considered random and treated as random variables. They are fitted by appropriate probability density functions before a further quantitative reliability analysis is taken. Some elementary concepts of system reliability are then employed to estimate the reliability of an existent piping system by taking these random factors into consideration. A numerical example is given at the end of the present study. The example illustrates the use of the proposed analysis in the reliability assessment of a piping system existed in a German nuclear power plant. It is found that the failure probability of the piping system is 5.4*10^{-7} per weld area and 1.4*10^{-10} for the entire system