Characterization of the fatigue behaviors of offshore hyperbarik welds
Başlık çevirisi mevcut değil.
- Tez No: 29096
- Danışmanlar: DOÇ. DR. SEÇİL ERİM
- Tez Türü: Yüksek Lisans
- Konular: Makine Mühendisliği, Mechanical Engineering
- Anahtar Kelimeler: Kaynak, Kaynak bağlantısı, Su altı çalışmaları, Çelik yapılar, Welding, Weld joint, Underwater surveys, Steel structures
- Yıl: 1993
- Dil: İngilizce
- Üniversite: Dokuz Eylül Üniversitesi
- Enstitü: Fen Bilimleri Enstitüsü
- Ana Bilim Dalı: Makine Mühendisliği Ana Bilim Dalı
- Bilim Dalı: Belirtilmemiş.
- Sayfa Sayısı: Belirtilmemiş.
Özet
Özet yok.
Özet (Çeviri)
SUMMARY The use of arc welding process in repair and montage of the underwater steel structures depends strongly to the fracture toughness and fatigue properties of the welded joints. Presence of the pressure at greater sea-water depths affects the welding process and may further deteriorates the mechanical properties of the underwater welded joints. Therefore, this present study has been carried out to determine the effect of pressure on the fatigue life of small scale specimens (width=15 mm, thickness=5 mm). A large number of butt-welded specimens, in as- welded condition have been obtained from 15 mm wide offshore steel plates with V preparation welded with MIG/MAG processes under atmospheric (1 bar), 15 bar and 27 bar dry conditions. In the experimental part of the study, constant amplitude fatigue tests in air have been performed at the hydraulic testing machine by keeping the stress ratio (tfmin/smax)» R=0.1 constant The applied load values were varied between a maximum of 32 kN and a minimum of 12 kN. The results are plotted on logS-logN diagrams. The bi-linear S-N curve fitting method developed by Japanese scientists, which is based on a statistical approach of fitting data to a bi linear type of curve comprising inclined and horizontal lines, is used in the study. Weld toe angle versus fatigue life diagrams are constructed to determine whether the fatigue life gets shorter as the toe angle at which the crack initiates decreases. In the second part of this study, a statistical analysis of the scatter of the fatigue life data has been carried out. The results of fatigue tests for each pressure level are statistically compared to decide whether there is significant difference between the results or whether they can be treated as one set of data. Calculations were carried out to determine the confidence limits and 10%, 50%, 90% survival curves associated with the test results. The test results show that fatigue cracks in the butt welded joints always initiate at the weld region, mostly at one corner of the weld toes. From the weld toe angle versus fatigue life diagrams, though not clearly defined due to data scatter, it is observed that there exists a direct relationship between the weld toe angle of crack initiation site and the fatigue life of the specimen. Also it is clear that the scatter of fatigue lives tends to increase as the applied stress level is decreased. From the statistical analysis it is determined that the data obtained for three pressure levels were not significantly different and could be treated as one set of data. In other words, no effect of pressure can be observed on fatigue life of the hyperbaric butt-welds. This may be due to the fact that the effect of similar toe geometry, that is the change of section at the weld region, overcomes the differences in the mechanical properties of the welds.
Benzer Tezler
- GGG 40 sınıfı küresel grafitli dökme demirlerin yorulma davranışına tin kaplamanın etkisi
Başlık çevirisi yok
GÖKHAN BAŞMAN
Yüksek Lisans
Türkçe
1998
Metalurji Mühendisliğiİstanbul Teknik ÜniversitesiMetalurji Mühendisliği Ana Bilim Dalı
DOÇ. DR. M. KELAMİ ŞEŞEN
- Az alaşımlı karbon çeliği beton çubuklarının sürünme davranışları ve mikroyapısal karakterizasyonu
Creep behaviour and microstructural characterization of low-alloyed carbon steel reinforcing bars
İLKSEN COŞAR
- Kent mobilyalarının etkin kullanım alanı olarak parkların incelenmesi, Maçka Demokrasi Parkı ve Bakırköy-Samatyalı Sahil Parkı
Parks as active usage areas of urban furnitures, Maçka Demokrasi Park and Bakırköy-Samatya coast park
EMİNE KARAMAN
Yüksek Lisans
Türkçe
2000
Şehircilik ve Bölge Planlamaİstanbul Teknik ÜniversitesiDOÇ. DR. NİLGÜN ERGUN
- Mekanik alaşımlanmış intermetalik toz ve sinter Ti-47-5Al-3Cr alaşımının analitik elektron mikroskop ve x-ışınları teknikleri ile karakterizasyonu
Analytical election microscope and x-ray diffraction characterization of mechanically alloyd intermetallic Ti-47-5Al-3Cr powder and sinter
ARDA GENÇ
- Silisyum katkısının döküm CrNiCo süperalaşımının özelliklerine etkisi
Başlık çevirisi yok
HAVVA KAZDAL ZEYTİN
Doktora
Türkçe
1998
Metalurji Mühendisliğiİstanbul Teknik ÜniversitesiMetalurji Mühendisliği Ana Bilim Dalı
PROF. DR. ADNAN TEKİN