Case studies in engineering failure analysis最新文献_第3页

Assessment of circumferential cracks in hypereutectic Al-Si clutch housings 过共晶Al-Si离合器壳体周向裂纹的评定

Case studies in engineering failure analysis Pub Date : 2017-04-01 DOI: 10.1016/j.csefa.2016.11.003

M. Haghshenas , J. Jamali

{"title":"Assessment of circumferential cracks in hypereutectic Al-Si clutch housings","authors":"M. Haghshenas , J. Jamali","doi":"10.1016/j.csefa.2016.11.003","DOIUrl":"10.1016/j.csefa.2016.11.003","url":null,"abstract":"<div><p>As in situ natural composites with silicon phase acting as the reinforcing phase, Al-Si alloys are among most commonly used aluminum alloys in automotive applications (<em>i.e.</em> engine component). Silicon contributes to the strength of Al-Si alloys through load transfer from the Al matrix to the hard (rigid) Si phase in the microstructure (load-carrying capacity). Casting parameters (<em>i.e.</em> solidification rate, elemental segregation, secondary dendrite spacing…) as well as the size and distribution of the microstructural constituents in Al-Si alloys (<em>i.e.</em> morphology of Si particles, intermetallic compounds, secondary dendrite spacing) contribute directly to the mechanical response and failure (or fracture) behavior of the alloy within the service. In hyper-eutectic Al-Si alloys (<em>i.e.</em> B390.0), distribution of coarse pre-eutectic Si particle mainly contribute to stress concentration, crack initiation and propagation during the actual service condition. In the present paper, the parameters contribution to the formation of the circumferential cracks in clutch housings made of die cast hyper-eutectics B390.0 Al-Si alloys are assessed through optical microscopy and scanning electron microscopy. Casting variable, cooling rate, their effect on the cracks as well some of the possible causes are also discussed in detail.</p></div>","PeriodicalId":91224,"journal":{"name":"Case studies in engineering failure analysis","volume":"8 ","pages":"Pages 11-20"},"PeriodicalIF":0.0,"publicationDate":"2017-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.csefa.2016.11.003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44165778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 22

Failure investigation of a secondary super heater tube in a 140 MW thermal power plant 某140mw火电厂二次过热加热器管失效分析

Case studies in engineering failure analysis Pub Date : 2017-04-01 DOI: 10.1016/j.csefa.2017.05.001

Atanu Saha, H. Roy

引用次数: 22

Failure analysis of fire resistant fluid (FRF) piping used in hydraulic control system at oil-fired thermal power generation plant 燃油火电厂液压控制系统中耐火流体管道失效分析

Case studies in engineering failure analysis Pub Date : 2017-04-01 DOI: 10.1016/j.csefa.2017.01.001

Muhammad Akram , Muhammad Umair , Mujeeb-Ur-Rehman , Asim Iqbal

{"title":"Failure analysis of fire resistant fluid (FRF) piping used in hydraulic control system at oil-fired thermal power generation plant","authors":"Muhammad Akram , Muhammad Umair , Mujeeb-Ur-Rehman , Asim Iqbal","doi":"10.1016/j.csefa.2017.01.001","DOIUrl":"10.1016/j.csefa.2017.01.001","url":null,"abstract":"<div><p>This is a case study regarding frequent forced outages in an oil-fired power generating station due to failure of fire resistant fluid (FRF) piping of material <strong>ASTM A-304</strong>. This analysis was done to find out the most probable cause of failure and to rectify the problem. Methods for finding and analyzing the cracks include nondestructive testing techniques such as visual testing (VT) and dye penetrant testing (PT) along with that periodic monitoring after rectification of problem. The study revealed that pitting and pit to crack transitions were formed in stainless steel piping containing high pressure (system pressure 115 bars) fire resistant fluid. However, after replacement of piping the pitting and cracking reoccurred. It was observed that due to possible exposure to chlorinated moisture in surrounding environment pitting was formed which then transformed into cracks. The research work discussed in this paper illustrates the procedure used in detection of the problem and measures taken to solve the problem.</p></div>","PeriodicalId":91224,"journal":{"name":"Case studies in engineering failure analysis","volume":"8 ","pages":"Pages 21-27"},"PeriodicalIF":0.0,"publicationDate":"2017-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.csefa.2017.01.001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49382347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Failure analysis of a first stage IN738 gas turbine blade tip cracking in a thermal power plant 某火电厂IN738燃气轮机一级叶顶开裂失效分析

Case studies in engineering failure analysis Pub Date : 2017-04-01 DOI: 10.1016/j.csefa.2016.11.002

Sushila Rani, Atul K. Agrawal, Vikas Rastogi

{"title":"Failure analysis of a first stage IN738 gas turbine blade tip cracking in a thermal power plant","authors":"Sushila Rani, Atul K. Agrawal, Vikas Rastogi","doi":"10.1016/j.csefa.2016.11.002","DOIUrl":"10.1016/j.csefa.2016.11.002","url":null,"abstract":"<div><p>This research paper deals with the investigation of causes of failure of the first stage gas turbine blade of 30MW gas turbine having tip cracks at the trailing as well as leading edge. This blade is made of nickel based super alloy IN738LC, having directional solidified grain structure and contains aluminide coating (Pt–Al<sub>2</sub>) by diffusion process. The main focus of the paper is evaluation of tip crack at the trailing edge and further degradation of blade coating. The investigations included the visual observations, material composition analysis, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). During examination of the failed blade, it is found that the blade surface is completely degraded due to overheating. Corrosion pits are formed on the blade surface, these pits act as a notch to produce stress concentrations and cracks is initiated due to fatigue which further propagate due to hot corrosion. It is also reported that the Al-Pt coating is completely degraded, heavily oxidized. From these investigations, it is concluded that the failure of gas turbine blade takes place due to the combined effect of surface degradation caused by overheating, oxidation, hot corrosion and degradation of coating heavily oxidized.</p></div>","PeriodicalId":91224,"journal":{"name":"Case studies in engineering failure analysis","volume":"8 ","pages":"Pages 1-10"},"PeriodicalIF":0.0,"publicationDate":"2017-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.csefa.2016.11.002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45342276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 73

Damage analysis of the forced draft fan blade in coal fired power plant 燃煤电厂强制通风机叶片损伤分析

Case studies in engineering failure analysis Pub Date : 2017-04-01 DOI: 10.1016/j.csefa.2017.04.005

M. Nurbanasari, T. Kristyadi, T.S. Purwanto, A. Maulana, R.R. Fadilah

{"title":"Damage analysis of the forced draft fan blade in coal fired power plant","authors":"M. Nurbanasari, T. Kristyadi, T.S. Purwanto, A. Maulana, R.R. Fadilah","doi":"10.1016/j.csefa.2017.04.005","DOIUrl":"10.1016/j.csefa.2017.04.005","url":null,"abstract":"<div><p>The Forced Draft Fan (FDF) blade in a 300MW coal fired power plant that experienced catastrophic failure has been investigated. There were two main locations of the blade damage, namely damage at the root of the blade and the other one is at the third of the blade height. The FDF blade has been run for 5 years and before its failure, the FDF experienced high vibration (14mm/s). The forced draft fan is an axial flow fan horizontally in front of the boiler and the fan is single stage. Visual inspection, metallographic analysis, chemical composition and hardness test were carried out to find the cause of the failure. It is concluded that the material of the blade is cast Al-Si alloy (A356.0) that fits the requirements for FDF blade application, the failure of the third of the blade height is owing to the external particles collide to the leading edge of the blades causing erosion and notch. That notch acted as initial crack. The failure at the root blade was caused by broken fragments of the others damaged blades entered in between casing (stator) and the blade (rotor) so they obstructed the blade rotation.</p></div>","PeriodicalId":91224,"journal":{"name":"Case studies in engineering failure analysis","volume":"8 ","pages":"Pages 49-56"},"PeriodicalIF":0.0,"publicationDate":"2017-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.csefa.2017.04.005","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45518035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Investigation of a Columbus, Ohio train derailment caused by fractured rail 俄亥俄州哥伦布市一列火车因铁轨断裂而脱轨的调查

Case studies in engineering failure analysis Pub Date : 2016-10-01 DOI: 10.1016/j.csefa.2016.04.001

Frank Zakar, Erik Mueller

引用次数: 13

Bayesian analysis of low-cycle fatigue failure in printed wiring boards 印制板低周疲劳失效的贝叶斯分析

Case studies in engineering failure analysis Pub Date : 2016-10-01 DOI: 10.1016/j.csefa.2016.11.001

Rong Pan , Xinyue Xu , Joseph Juarez

引用次数: 2

Failure analysis of a half-shaft of a formula SAE racing car 方程式SAE赛车半轴失效分析

Case studies in engineering failure analysis Pub Date : 2016-10-01 DOI: 10.1016/j.csefa.2016.05.002

A.V. Guimaraes , P.C. Brasileiro , G.C. Giovanni , L.R.O. Costa , L.S. Araujo

引用次数: 15

Failure analysis of tube-to-tubesheet welded joints in a shell-tube heat exchanger 壳管式换热器管板焊接接头失效分析

Case studies in engineering failure analysis Pub Date : 2016-10-01 DOI: 10.1016/j.csefa.2016.06.002

Long Liu , Ning Ding , Junbo Shi , Na Xu , Weimin Guo , Chi-Man Lawrence Wu

{"title":"Failure analysis of tube-to-tubesheet welded joints in a shell-tube heat exchanger","authors":"Long Liu , Ning Ding , Junbo Shi , Na Xu , Weimin Guo , Chi-Man Lawrence Wu","doi":"10.1016/j.csefa.2016.06.002","DOIUrl":"10.1016/j.csefa.2016.06.002","url":null,"abstract":"<div><p>Failure analysis was carried out on a tube-to-tubesheet welded joint of a shell-tube heat exchanger to confirm its failure mechanism. The collected evidence suggests that the failure of the tube-to-tubesheet welded joint was induced by fatigue. Under the morphology analysis, the fracture surface exhibit obvious fatigue crack propagation traces. Fatigue striations were observed clearly in the propagation zone. Detecting results showed that chemical composition and mechanical properties of the tubes was consistent with the standard requirements for the 304 stainless steel. The metallographic test showed that the microstructure of both the tube and tubesheet were normal. However, serious defects were found at the tube-to-tubesheet welded joint. The fatigue crack initiated from the defects at the tube-to-tubesheet welded joint. The periodic load might come from the resonant vibration of the tube or the changes in temperature and pressure of the fluid inside the heat exchanger. Bad welding and unsuitable expansion position of the tubes at the tube-to-tubesheet might give rise to the formation of initial cracks.</p></div>","PeriodicalId":91224,"journal":{"name":"Case studies in engineering failure analysis","volume":"7 ","pages":"Pages 32-40"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.csefa.2016.06.002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54177244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 47

Report on fractures of trilayered all-ceramic fixed dental prostheses 三层全瓷固定修复体骨折报告

Case studies in engineering failure analysis Pub Date : 2016-10-01 DOI: 10.1016/j.csefa.2016.10.001

Renan Belli , Susanne S. Scherrer , Ulrich Lohbauer

引用次数: 20