کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7171630 | 1463715 | 2018 | 11 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
A study on fatigue behavior of MIG-welded Al-Mg alloy with different filler-wire materials under mean stress
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موضوعات مرتبط
مهندسی و علوم پایه
سایر رشته های مهندسی
مهندسی مکانیک
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چکیده انگلیسی
Cylindrical specimens of Ï5â¯mm were cut from the weld bead of 50â¯mm thick MIG-welded Al-Mg alloy (Al-5083) plates with two different filler materials: Al-5183 (commonly used) and Al-5.8%Mg (special hardened new alloy). Load-controlled fatigue tests were done at different stress-ratios (R=-1,-0.5,0.1,0.5) using sinusoidal wave at 30â¯Hz and the performance of three popular finite-life empirical models: Gerber's parabola, Smith-Watson-Topper's model and Walker's model, was studied using the experimental data. Fatigue lives and endurance limits of both materials did not differ significantly, but they got reduced when the R-ratio was increased and the endurance limit followed the Gerber's parabola. A non-monotonic trend in the slope of S-N curves was observed: first increases and then decreases. Fracture surface observations revealed majority of surface-initiated failures at lower R-ratios (-1,-0.5), while for higher R-ratios (0.1,0.5), defect-induced failures were predominant. This shift in crack initiation site was attributed to the local cyclic plasticity due to stress-concentration and demonstrated using elastic-plastic finite element (FE) simulations. The detrimental effect of mean-stress on fatigue lives was attributed to combined effects of reduction in crack-nucleation time: due to stress concentration at defects and the crack closure effects. The three fatigue life models predicted monotonic decrease in slopes of S-N curves and thus did not give best results. A new model, based on Walker's model, was proposed which was able to capture the observed non-monotonic trend of the slopes of S-N curves and predicted fatigue lives better than these models.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Fatigue - Volume 107, February 2018, Pages 119-129
Journal: International Journal of Fatigue - Volume 107, February 2018, Pages 119-129
نویسندگان
Vidit Gaur, Manabu Enoki, Toshiya Okada, Syohei Yomogida,