Strength, Fracture and Complexity最新文献

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An error-analysis-based multi-scale reliability model for predicting the minimum time-to-failure of brittle components with environment-assisted crack growth 基于误差分析的多尺度可靠性模型，用于预测有环境辅助裂纹生长的脆性部件的最短失效时间

Strength, Fracture and Complexity Pub Date : 2024-07-27 DOI: 10.3233/sfc-230020

J. Fong, N. Heckert, Stephen W. Freiman

{"title":"An error-analysis-based multi-scale reliability model for predicting the minimum time-to-failure of brittle components with environment-assisted crack growth","authors":"J. Fong, N. Heckert, Stephen W. Freiman","doi":"10.3233/sfc-230020","DOIUrl":"https://doi.org/10.3233/sfc-230020","url":null,"abstract":"We developed an error-propagation-analysis-based multi-scale reliability model in three steps to estimate the minimum time-to-failure of a full-size brittle component with environment-assisted crack growth. First, we use a time-to-failure formula according to Fuller et al. (1994), which was based on laboratory experiments on brittle materials for measuring time-to-failure of specimens that undergo moisture-enhanced crack growth under constant stressing. The formula predicted the mean time-to-failure of a specimen-size component in a power-law relationship with the applied stress involving two strength test parameters, S and Sv, and two constant stressing test parameters from regression analysis, 𝜆 and N′. Second, we use the classical laws of error propagation to derive a formula for the standard deviation of the time-to-failure of a specimen-size component and apply it to computing the standard deviation of the time-to-failure of a specimen-size component for a specific applied stress. Third, we apply the statistical theory of tolerance intervals and develop a conservative method of estimating the failure probability of the full-size components by introducing the concept of a failure probability upper bound (FPUB). This allows us to derive a relationship for the minimum time-to-failure, min-tf, of a full-size brittle component at a specific applied stress as a function f of the FPUB. By equating (1 – FPUB) as the Reliability Lower Bound, RELLB, we arrive at a relation, min-tf = f (RELLB), which expresses the min. time-to-failure as a function of the reliability lower bound, or conservatively as a function of reliability.","PeriodicalId":507068,"journal":{"name":"Strength, Fracture and Complexity","volume":"80 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141798220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Fatigue load spectrum generation of Indonesian high-speed trains 印尼高速列车疲劳载荷谱的生成

Strength, Fracture and Complexity Pub Date : 2024-02-27 DOI: 10.3233/sfc-230015

Hery Setiawan, Ichsan Setya Putra, Latif Nurrahman, I. M. Wiragunarsa, Intan Sibarani, Annisa Jusuf, Bambang Raharjo

引用次数: 0

Failure analysis of S30408 pipe cracking and preventive measures S30408 管材开裂的失效分析和预防措施

Strength, Fracture and Complexity Pub Date : 2024-01-29 DOI: 10.3233/sfc-230018

Dongxuan Bi, Zizhen Zhao, Ming Zhang, Mengli Li, Yancai Su

{"title":"Failure analysis of S30408 pipe cracking and preventive measures","authors":"Dongxuan Bi, Zizhen Zhao, Ming Zhang, Mengli Li, Yancai Su","doi":"10.3233/sfc-230018","DOIUrl":"https://doi.org/10.3233/sfc-230018","url":null,"abstract":"BACKGROUND: The feed pipeline made from 30408 stainless steel of a new unit leaked during the air pressure test. OBJECTIVE: The present work aims to examine the specific cause of pipeline cracking, and providing effective approaches to avoid similar failures. METHODS: Macroscopic inspections of the cracked pipe defects were made on site immediately after leakage. Mechanical properties and hardness of specimens machined from the failed pipe were tested. In addition, microscopic analyses including material composition, microstructure observation and crack morphologies of the failed part were performed to get detail information. Composition of the feed raw material was also analyzed to identify whether it had been contaminated by corrosive elements or not. RESULTS: No impurity composition was found in the feed raw material. The element constituents, yield strength, tensile strength and hardness of the cracked pipe fulfill standard requirements. A number of scratches and defects with a size of several microns were found on the inner wall of the leaked pipe, and they were believed to be formed at the perforation step during pipeline processing. Liquation cracks were found at the pipeline butt weld joint, and they laid hidden dangers for the safety and steady operation of the pipeline. CONCLUSION: The overall analysis results indicated the pipeline leakage during air pressure test was caused by cracks initiated around inner wall defects, which sabotaged the bearing capacity of the pipe by wall thickness reduction and stress concentration. Therefore, improving the inner wall surface quality at the perforation step may help to avoid such failure. The metallurgical effect and weld stress caused during the welding process promoted the initiation and propagation of liquation cracks. The tendency of welding hot crack formation could be reduced by taking strict composition control of the welding rod and adopting reasonable welding parameters.","PeriodicalId":507068,"journal":{"name":"Strength, Fracture and Complexity","volume":"159 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140485915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0