Overload induced retardation in 2024-T3 aluminum sheets
2024-T3 Aluminyum plakalarda yorulmanın aşırı yüklerle geciktirilmesi
- Tez No: 29067
- Danışmanlar: PROF. DR. ÖKTEM VARDAR
- Tez Türü: Yüksek Lisans
- Konular: Makine Mühendisliği, Mechanical Engineering
- Anahtar Kelimeler: Alüminyum alaşımları, Aşırı yük, Yorulma dayanımı, Çatlak, Aluminum alloys, Overload, Fatigue strength, Crack
- Yıl: 1993
- Dil: İngilizce
- Üniversite: Boğaziçi Üniversitesi
- Enstitü: Fen Bilimleri Enstitüsü
- Ana Bilim Dalı: Makine Mühendisliği Ana Bilim Dalı
- Bilim Dalı: Belirtilmemiş.
- Sayfa Sayısı: Belirtilmemiş.
Özet
Özet yok.
Özet (Çeviri)
61 IV. SUMMARY AND CONCLUSIONS Periodic overload tests have been conducted on M(T) specimens made from five mm thick 2024-T3 AT clad aluminum alloy for a load ratio R=0.11, with the resulting baseline AK value typical of Region II of the Paris plot. OLR was kept constant, i.e. 1.65, whereas OCR varied from 1/3 to 1/15000 among 10 values. In addition a few single overload tests have been performed to clarify the effect of AK on retardation. Based on the experimental results and subsequent discussion, the follo wing conclusions may be drawn: (1) Periodic overloads, with all the OCR values, except 0CR=1/3, employed in this study, provide additional life or caused retardation in crack growth. However, steadily decrease in retardation as OCR approaches to "4 clearly shows that acceleration with respect to constant amplitude life should be expected when OCR <4. (2) The maximum life occurs at OCR=1/7500, i.e. ~22 times that of constant amplitude, for crack growth between 20 and 30 mm. For -i -1 OCR <7500and OCR >7500 corresponding fatigue lives are observed to decrease with different slopes on logarithmic plot. (3) Periodic overload growth rates obtained for only those values of OCR where smooth crack growth curves obtained are shown to be reduced by a factor of AN/ANca at the equivalent loading conditions, i.e. baseline AK. The greatest reduction occurs when AN/ANca is maxi mum which 1s evidently when OCR= 1/7500.62 (4) The experiments which are started close to the notch showed great differences from the experiments which are started far enough from the notch. (5) Turn-off during the night has no influence on fatigue crack propagation for the present test conditions. (6) As NCA decreases or the number of overloads Increases shear lips develop earlier, that is, earlier transition to plane stress takes place. Limited data show that periodic overload behaviour under plane stress and plane strain is the same. (7) The fact that band width of overload induced markings is less than the expected single overload band width of the same baseline AK suggests that AKeff has been reduced in periodic overload spectrum.
Benzer Tezler
- Comparison of retardation behavior of 2024-T3 and 7075-TG al-alloys
Başlık çevirisi yok
CEM ERTUNGA ÇELİK
Yüksek Lisans
İngilizce
1994
Makine MühendisliğiBoğaziçi ÜniversitesiMakine Mühendisliği Ana Bilim Dalı
PROF. DR. ÖKTEM VARDAR
- Periodic tensile overloads in 2024-T3
Başlık çevirisi yok
YAHYA KEMAL TÜR
Yüksek Lisans
İngilizce
1993
Makine MühendisliğiBoğaziçi ÜniversitesiMakine Mühendisliği Ana Bilim Dalı
PROF. DR. ÖKTEM VARDAR
- Tavşanlarda deneysel olarak aşırı demir yüklenmesiyle eritrositlerde oluşturulan akut oksidatif hasar üzerine E vitamini ve melatonin etkilerinin karşılaştırılması
The Comparison of effects of vitamin E and melatonin on acute oxidative damage in the erythrocytes induced by iron overload in rabbits
HALİT KARACA
Doktora
Türkçe
1999
FizyolojiSüleyman Demirel ÜniversitesiFizyoloji Ana Bilim Dalı
PROF. DR. SADETTİN ÇALIŞKAN
- Melatonin'in fizyolojik ve farmakolojik konsantrasyonlarının miyokardiyal iskemi-reperfüzyona bağlı aritmiler ve nekroz üzerine etkileri
Effects of physiological and pharmacological concentrations of melatonin on myocardial ischemia-reperfusion induced arrhythmias and necrosis
ENGİN ŞAHNA
Doktora
Türkçe
2001
Eczacılık ve Farmakolojiİnönü ÜniversitesiFarmakoloji Ana Bilim Dalı
PROF.DR. AHMET ACET
- Defibrotid ile tedavinin tavşan karotid arterinde intimal kalınlaşma ve vasküler reaktivite üzerine etkisi
Başlık çevirisi yok
GÜLNUR SEVİN