Vol.3, No 13, 2003 pp. 671-688
UDC 539.388.1  539.219.2
EFFICIENT ENGINEERING APPROACHES FOR THE PREDICTION OF FATIGUE PROPAGATION OF CORNER CRACKS IN THE CASE OF MULTIPLE SITE DAMAGE
G. Labeas, Th. Kermanidis, J. Diamantakos
Laboratory of Technology and Strength of Materials
Department of Mechanical Engineering & Aeronautics
University of Patras, Patras 26500, Greece
The prediction of fatigue propagation of corner cracks in the case of Multiple Site Damage is a complicated task since the calculation of the Stress Intensity Factors requires three-dimensional stress analysis of the structure. In the present work, two methodologies aiming in treating the three-dimensional nature of a corner crack growth problem by performing equivalent two-dimensional analysis are presented. The first approach provides a simple procedure for the substitution of a corner crack by an equivalent through crack. In the second approach the corner crack propagation is treated by two-dimensional analysis, by exploiting the benefits of the sub-modelling technique of the Finite Element Method (FEM), thus the necessity of the three-dimensional analysis is limited only in the corner cracks adjacent areas. Both approaches are verified for the case of single corner crack propagation, as well as, Multiple Site Damage corner crack propagation.
EFIKASNI TEHNIČKI PRISTUPI PREDVIDJANJU ŠIRENJA ZAMORA UGAONIH PRSLINA U SLUČAJU OŠTEĆENJA
NA VIŠE POLOŽAJA
Predvidjanje širenja zamora ugaonih prslina u slučaju oštećenja na više položaja složen je zadatak, pošto izračunavanje faktora intenziteta napona zahteva trodimenzionalnu analizu napona strukture. U ovom radu prikazane su dve metode usmerene ka tretiranju trodimenzionalne prirode problema napredovanja ugaone prsline putem vršenja ekvivalentnih dvodimenzionalnih analiza. Prvi pristup pruža jednostavnu proceduru zamene ugaone prsline ekvivalentnom prolaznom prslinom. U drugom pristupu, prostiranje ugaone prsline tretira se preko dvodimenzionalne analize, korišćenjem prednosti tehnike podmodeliranja metode konačnog elementa (FEM), čime je neophodnost trodimenzionalne analize ograničena samo u oblastima neposredno uz ugaone prsline. Oba pristupa proverena su za slučaj prostiranja jedne ugaone prsline, kao i za prostiranje ugaone prsline kod oštećenja na više položaja.