Vol.1, No 9, 2002 pp. 1231 - 1239
UDC 620.152.2/.4=861
COMPUTER SIMULATION OF CUMULATIVE
FATIGUE DAMAGE
Zoran Perović
Faculty of Mechanical Engineering, University of Montenegro
Cetinjski put bb, 81000 Podgorica, E-mail: zoranp@cg.ac.yu
Abstract. Computer simulation of cumulative fatigue damage of welded
joint subjected to variable-amplitude loading is presented in this paper.
The crack growth rate for a given material is expressed as a function of
an effective range of stress intensity factor in order to account for both
short and long crack behaviour. The correction factors in the equation
of stress intensity factor were determined by Gross' and Albrecht's methods.
The fatigue life is calculated by solving the equation of fatigue crack
growth rate from a0 to af
by Runge-Kutta method. A computer program, based on this procedure,
is used for the fatigue crack growth simulation. The obtained results were
compared with the fatigue life determined by using Miner's rule, determining
the error of the latter in the region near the variable-amplitude fatigue
limit.
Key words: cumulative fatigue damage, computer simulation,
short and long crack, local plastic zone.
KOMPJUTERSKA SIMULACIJA AKUMULACIJE
ZAMORNOG OŠTEĆENJA
U ovom radu je prikazana kompjuterska simulacija akumulacije zamornog oštećenja
u zavarenom spoju izloženom opterećenju sa promjenljivom amplitudom. Brzina
rasta zamorne prsline za dati materijal je izražena kao funkcija od DeltaKeff
u cilju obuhvatanja ponašanja i kratke i duge prsline. Korekcioni faktori
u izrazu za K-faktor su određeni kombinacijom Gross-ove i Albrecht-ove
metode. Zamorni vijek je izračunat rješavanjem jednačine brzine rasta zamorne
prsline od a0 do af
pomoću metode Runge-Kutta. Kompjuterski program, baziran na ovoj proceduri,
korišćen je za simulaciju rasta zamorne prsline. Dobijeni rezultati su
upoređeni sa zamornim vijekom određenim pomoću Miner-ovog pravila. Na ovaj
način je određena greška Miner-ovog pravila za područje u blizini zamorne
čvrstoće za promjenljivu amplitudu.
