Publications (5) View all
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Article: A thermo-mechanical fatigue damage model for variable temperature and loading amplitude conditions
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ABSTRACT: A fatigue life prediction method for thermo-mechanical fatigue damage under variable temperature and loading amplitudes was proposed. In this approach, a rainflow cycle counting technique was used to extract cycle counts from the mechanical loading history. For each loading cycle, an equivalent damage temperature was determined. Once the equivalent temperature was used, the loop would be guaranteed closed. This approach was based on the assumption that total fatigue damage is defined as the summation of mechanical fatigue damage and oxidation damage. The mechanical fatigue damage was calculated based on the Smith–Watson–Topper (SWT) model at room temperature, while the oxidation damage was calculated based on the Sehitoglu model determined from the stress/strain data at the equivalent temperature. Finally, Miner’s linear damage rule was used for damage accumulation. A case study with automotive exhaust systems was conducted to verify the effectiveness of the proposed method. The effect of creep damage was excluded in this study.International Journal of Fatigue. -
Article: Effect of geological anomalies on longwall face support : a finite element modeling approach /
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ABSTRACT: Thesis (M.M.N.)--University of Alabama, 1996. Includes bibliographical references (leaves 78-81). -
Article: Fatigue analysis of spot welds subjected to combined tension and shear loading /
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ABSTRACT: Thesis (Ph. D.)--University of Alabama, 1999. Includes bibliographical references (leaves 119-124). -
Article: Fatigue analysis of spot welds using a mesh-insensitive structural stress approach
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ABSTRACT: This paper describes the application procedures of a nodal force based mesh-insensitive structural stress parameter for analysis of a comprehensive set of spot weld fatigue test data collected from a series of advanced high strength sheet steels. The structural stress parameter is calculated in an equilibrium sense in terms of bending and membrane components from nodal forces and moments at each grid point along the periphery of a weld nugget. Based on fracture mechanics considerations, an equivalent structural stress parameter is then used to take into account the effects of loading mode and sheet thickness on the fatigue of spot welded joints. The equivalent structural stress is proven effective in consolidating the large amount of fatigue data of spot welds for transformation induced plasticity (TRIP), dual-phase (DP), and high strength low alloy (HSLA) steels subjected to both tensile shear and coach peel loadings. As a result, a single master S–N can be established for fatigue design and life prediction of spot-welded structures.International Journal of Fatigue. -
Article: Effect of prestrain paths on mechanical behavior of dual phase sheet steel
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ABSTRACT: The tensile and fatigue performance of dual phase (DP600) sheet steel was investigated with specimens, as-received, and with two different prestrain path conditions, uniaxial and plane strain. First, tensile tests of the as-received condition of DP600 were performed to obtain mechanical properties, specifically the uniform elongation, for determining the prestrain levels of the specimens. Then three prestrain levels from each strain path were applied onto the sheet steel. Tensile and fatigue specimens were prepared from the prestrained coupons. Mechanical properties were obtained from the uniaxial tests of the as-received and prestrained specimens for comparison. Fatigue testing was also conducted with strain controlled to acquire fatigue properties. The fatigue life curves were plotted as a function of strain range and Neuber factor. The uniaxially prestrained specimens exhibited higher fatigue strength than that of the as-received ones for the long life region, but the opposite effect was observed for the short life region of less than 104 reversals.International Journal of Fatigue.
