From monoscale to multiscale modeling of fatigue crack growth:stress and energy density factor
The formalism of the earlier fatigue crack growth models is retained to account for multiscaling of the fatigue process that involves the creation of macrocracks from the accumulation of micro damage.The effects of at least two scales,say micro to macro,must be accounted for.The same data can thus be reinterpreted by the invariancy of the transitional stress intensity factors such that the microcracking and macrocracking data would lie on a straight line.The threshold associated with the sigmoidal curve disappears.Scale segmentation is shown to be a necessity for addressing multiscale energy dissipative processes such as fatigue and creep.Path independency and energy release rate are monoscale criteria that can lead to unphysical results,violating the first principle.Application of monoscale failure or fracture criteria to nanomaterials is taking toll at the expense of manufacturing super strength and light materials and structural components.This brief view is offered in the spirit of much needed additional research for the reinforcement of materials by creating nanoscale interfaces with sustainable time in service.The step by step consideraton at the different scales may offer a better understanding of the test data and their limitations with reference to space and time.
multiscale fatigue monoscale dualscale stress intensity energy density macro micro nano spatial-temporal crack stability sustaibale time
G.C.Sih
International Center for Sustainability,Accountability and Eco-Affordability of the Large and Small(ICSAELS)Lehigh University,Bethlehem,PA 18015,USA;Key Laboratory of Pressure Systems and Safety,Ministry of Education,School of Mechanical Engineering,East China University of Science and Technology,Shanghai 200237,China
国际会议
International Conference on Airworthiness & Fatigue -7th ICSAELS Series Conference(大飞机安全性能与疲劳国际会议)
北京
英文
43-58
2013-03-24（万方平台首次上网日期，不代表论文的发表时间）