An analysis on overall crack-number-density of short-fatigue-cracks
نویسندگان
چکیده
The evolution of dispersed short-fatigue-cracks is analysed based on the equilibrium of crack-number-density (CND). By separating the mean value and the stochastic ̄uctuation of local CND, the equilibrium equation of overall CND is derived. Comparing with the mean-®eld equilibrium equation, the equilibrium equation of overall CND has dierent forms in the expression of crack-nucleation-rate or crack-growth-rate. The simulation results are compared with experimental measurements showing the stochastic analyses provide consistent tendency with experiments. The discrepancy in simulation results between overall CND and mean-®eld CND is discussed. Ó 1999 Elsevier Science Ltd. All rights reserved.
منابع مشابه
Effect of Grain Size on Collective Damage of Short Cracks and Fatigue Life Estimation for a Stainless Steel
In the short crack regime of the fatigue process, grain boundaries in steels are barriers against crack growth. In this paper, we use: (1) a method involving crack density; and (2) a method of dimensional analysis, to evaluate the effects of grain size and grain-boundary resistance on short crack behaviour and fatigue life. The results show that the fatigue life increases with a decrease in gra...
متن کاملNUMERICAL INVESTIGATION OF CRACK ORIENTATION IN THE FRETTING FATIGUE OF A FLAT ROUNDED CONTACT
The growth of slant cracks by fretting fatigue of a half plane in contact with a flat rounded pad was studied. The mode I and mode II stress intensity factors for cracks of various lengths and directions were calculated using the semi-analytical method of the distribution of dislocations, and their cumulative effect on the crack growth was investigated using the strain energy density criterion....
متن کاملEffects of randomness of grain boundary resistance on fatigue initiation life
In the framework of crack number density analysis, a theoretical investigation is carried out on the relationship between the statistical characteristics of fatigue initiation life and the stochastic growth of short fatigue cracks. The numerical results indicate that, compared with the influence of grain boundary resistance, the effect of the degree of randomness of crystallographic crack growt...
متن کاملThe Dc Electrical Potential Method for the Measumment of Fretting Cracks
As fretting fatigue cracks are initiated at an early stage of life, the fretting fracture process is dominated by the stable growth of cracks. Hence the measurement of crack length is very important. This paper demonstrates the suitability of the DC potential drop technique for the measurement of fretting cracks. A calibration has been established for monitoring crack growth in BS L65 copper al...
متن کاملAn Outrun Competition of Corrosion Fatigue and Stress Corrosion Cracking on Crack Initiation in a Compressor Blade
First row rotating blades of four axial-flow compressors were prematurely fractured. Previous investigations showed that the site atmosphere contains corrosive compounds which lead to an increase in possibility of pitting on the blades. It was also revealed that the crack was originated from two corrosion pits. Thus, this work is conducted to ascertain which of fatigue or stress corrosion crack...
متن کامل