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• Main Authors: Wang, Chuu-Ming, 王楚明
• Other Authors: Yuan-Ching Ko ; Yi-Chang Lin
• Format: Others
• Language: zh-TW
• Published: 1993
• Online Access: http://ndltd.ncl.edu.tw/handle/40630544602109094285

碩士 === 國立臺灣大學 === 機械工程研究所 === 81 === AISI 304 stainless steel pipe has been widely used in engineering structures. A crack may initiate in the circumferential direction due to the action of thermal and vibratory stresses. It will propagate under the cyclic load. Eventually, the pipe will fracture when the residual ligament is too small to bear the external load. In this thesis, three aspects about pipe integrity have been studied. Firstly, a correct stress intensity expression is established to ensure accurate fatigue life prediction for circumferentially cracked piping. Then, the possibility of retarding such a crack was investigated. Finally, the fracture behaviour of cracked piping was studied. In the first part of work, the similarity principle and strain gage method was used to measure stress intensity factor for pipe with circumferential through-crack. The result of using principle was very closed to the analytic solution derived by Sanders. It was found that the strain gage method underestimates. The possible reason is that only four coefficients were used in the description of crack tip stress distribution. Secondly, the drill hole method, overload retardation and vacuum-infiltrating material into the crack flanks had been used to repair crack. It was found that the hole drilling method induced maximun retardation if the crack propagates into the hole. The degree of retardation for the vacuum-infilrating material method was dependent on whether the infilration was successful or not.