Abstract




 
   

IJE TRANSACTIONS A: Basics Vol. 26, No. 1 (January 2013) 25-32   

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  FATIGUE LIFE OF REPAIRED WELDED TUBULAR JOINTS
 
G. H. Farrahi, G.H. Majzoobi, A.H. Mahmoudi and N. Habibi
 
( Received: August 08, 2012 – Accepted: August 30, 2012 )
 
 

Abstract    In this study, the effect of repair on fatigue life of tubular joints is investigated. Six cracked specimens precedently subjected to fatigue loading undergone to weld repair. Two of those specimens were shot peened before primary fatigue loading. It is shown that repair gives rise to about 150% increase in fatigue life for original specimens while the increase of fatigue life for shot-peened and repaired specimens is around 105%. The in depth residual stresses are measured on the repaired joints before and after fatigue loading. It can be stated that repair made a remarkable improvement into fatigue behaviour of tubular joints examined in this investigation. However, if repair is not possible, shot peening can be a good alternative to improve the fatigue life of welded joint but if repair is planned, shot peening may not be financially or technically justifiable.

 

Keywords    Fatigue, Repair, Welded joint, Residual stress, Shot peening

 

چکیده   

موضوع اين تحقيق اثر تعمير بر عمرخستگی اتصالات لوله ای است. شش نمونه ترکدار که قبلا تحت بارگذاری خستگی قرار گرفته بود، تعمير شدند. دو عدد از اين نمونه ها قبل از بارگذاری اوليه خستگی، ساچمه زنی شدند. نشان داده شد که تعمير، عمر نمونه های ساچمه زنی نشده را حدود 150 درصد افزايش می دهد. افزايش عمر نمونه های ساچمه زنی شده تعميری حدود 105 درصد می باشد. تنش پسماند در سطح و عمق نمونه های تعميری قبل و بعد از بارگذاری خستگی اندازه گيری شد. نتايج نشان داد که تعمير باعث افزايش قابل توجه عمرخستگی اتصالات لوله ای مورد مطالعه اين تحقيق گرديد. چنانچه تعمير امکان پذير نباشد، ساچمه زنی راهکار خوبی جهت افزايش عمر خستگی اتصالات جوشی است ولی اگر تعمير در دستور کار قرار داشته باشد، آنگاه ساچمه زنی اين اتصالات از نظر اقتصادی و فنی قابل توجيه نخواهد بود.

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