THE APPLICABILITY OF MACROSCOPIC CONTINUUM MECHANICS TO FATIGUE LIFE PREDICTION
Fatigue damage is a result of material structural change at the microscopic scale such as dislocations of the atomic structures.While it would be ideal to model the fatigue process at the atomistic scale,the practical engineering design and evaluation of the load-bearing structures rely on the theories based on the classical continuum mechanics.A polycrystalline material consists of grains oriented in different directions.In macroscopic continuum mechanics,a material point is assumed to be a corpuscle so that it can be treated as a mathematical point but it is large enough to contain at least several grains to satisfy the homogeneous condition.The mismatch between the fatigue mechanisms at microscopic scale and the bulk consideration of the stress and strain based on the continuum mechanics concept will be discussed.Results obtained from a recently developed unified approach for fatigue life predictions will be used to address the applicability of the classical continuum mechanics for the fatigue life predictions of the engineering components.An emphasis will be placed on the determination of the crack tip plasticity using the elastic-plastic finite element stress analysis and the element size dependence of the predicted results.Some contradictions in fatigue modeling will be addressed.
Yanyao Jiang
University of Nevada,Reno,Department of Mechanical Engineering(312),Reno,NV 89557,USA
国际会议
第二届国际非均质材料力学会议(The Second International Conference on Heterogeneous Material Mechanics)
安徽黄山
英文
1213
2008-06-03（万方平台首次上网日期，不代表论文的发表时间）