| The paper aims at introducing knowledge of cyclic plasticity and fatigue crack, and making analysis of some constitutive models, including Chaboche, Ohno-Wang , McDowell and Jiang-Sehitoglu(JS) model. Adopted finite method(FE) simulation(ABAQUS) in order to obtain the stress-strain responses near the crack tip for elastic-perfectly plastic(EPP),Bilinear(BL),Chaboche and Jiang-Sehitoglu(JS) model. Made some conclusions concerning constitutive models after comparison and analysis.Jiang-Sehitoglu(JS) cyclic plasticity model combined with the multiaxial fatigue criterion was implemented into the finite element (FE) simulation for crack growth rate near the crack tip and determined number of cycles needed for obtaining stabilization of crack growth rate. Made analysis of cyclic plastic deformation, residual stress, stress amplitude,r-ratio effective and other related mechanics properties near the crack tip. The main work is to study the influence of element type and element size on these mechanics properties. Material 1070 steel was used in the investigation. Three-node bilinear, four-node bilinear and eight-node quadratic plane elements are adopted in the FE simulations. Finite element size near the crack tip is ranged from 0.007mm to 0.24mm, and the minimum elements are distributed within the x-axis from near the crack tip and certain height along y-axis. The ratio of length and width of minimum element is 1:1, and the density of elements becomes sparse when deviating from crack tip. The assessment of the influence of the element type and size was based upon the comparison of the predicted crack growth rate with experimental observation. Finally,proper element type and element size in the fatigue plasticity analysis was introduced.
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