Fatigue Life Prediction of Polycrystals under Multiaxial Straining
In the high cycle fatigue,the initiation of fatigue cracks is significantly affected by microstructure,loading conditions,and specimen geometry.However,fatigue life estimation traditionally considers microstructure and geometric effects via semi-empirical methods without explicit consideration of the early stages of crack formation,which tends to dominate the total lives in high cycle fatigue.Such a strategy has been useful for existing materials that have been characterized with extensive fatigue experiments,but is less applicable to the design of fatigue-resistant alloys or modification of existing alloy microstructures to enhance fatigue resistance.This paper employs a framework developed to assess the early stages of crack formation and growth through the microstructure in smooth and notched specimens.The methodology employs finite element simulations that render an unimodal grain-size microstructure and a crystal plasticity-based fatigue model that estimates 3D transgranular fatigue growth on a grain-by-grain basis.The crystal plasticity model parameters were calibrated for Ni-base superalloy RR1000.In these simulations,cracks form in near surface grains with highest slip-based driving force and then propagate through the field of adjacent grains.
Fatigue Indicator Parameter Microstructurally Small Cracks Fatigue Life
Gustavo M.Castelluccio David L.McDowell
Woodruff School of Mechanical Engineering Georgia Institute of Technology,771 Ferst Drive,N.W,Atlant Woodruff School of Mechanical Engineering Georgia Institute of Technology,771 Ferst Drive,N.W,Atlant
国际会议
北京
英文
1-10
2013-06-16（万方平台首次上网日期，不代表论文的发表时间）