کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
780893 1463784 2013 16 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Microstructure and load sensitive fatigue crack nucleation in Ti-6242 using accelerated crystal plasticity FEM simulations
موضوعات مرتبط
مهندسی و علوم پایه سایر رشته های مهندسی مهندسی مکانیک
پیش نمایش صفحه اول مقاله
Microstructure and load sensitive fatigue crack nucleation in Ti-6242 using accelerated crystal plasticity FEM simulations
چکیده انگلیسی

This paper investigates microstructure and load sensitive fatigue behavior of Ti-6242 using cyclic crystal plasticity finite element (CPFE) simulations of statistically equivalent image-based microstructures. A wavelet transformation induced multi-time scaling (WATMUS) method [1] and [2] is used to perform accelerated cyclic CPFE simulations till crack nucleation, otherwise infeasible using conventional time integration schemes. A physically motivated crack nucleation model in terms of crystal plasticity variables [3] is extended in this work to predict nucleation. The crack nucleation model is based on dislocation pile-up and stress concentration at grain boundaries, caused by inhomogeneous plastic deformation in the polycrystalline microstructure. The model is calibrated and validated with experiments. The dependence of yield strength on the underlying grain orientations and sizes is developed through the introduction of an effective microstructural parameter Plastic Flow Index or PFI. To determine the effects of the microstructure on crack nucleation, a local microstructural variable is defined in terms of the surface area fraction of soft grains surrounding each hard grain or SAFSSG. Simulations with different cyclic load patterns suggest that fatigue crack nucleation in Ti-6242 strongly depends on the dwell cycle hold time at maximum stress.


► Investigates microstructure and load sensitive fatigue behavior of Ti-6242.
► Image-based crystal plasticity FEM simulations for fatigue crack nucleation.
► Wavelet transformation induced multi-time scaling method for accelerated CPFEM.
► Plastic flow index for yield strength dependence on grain morphology.
► Surface area of soft grains surrounding hard grains to indicate crack nucleation.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Fatigue - Volume 48, March 2013, Pages 231–246
نویسندگان
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