FINITE-ELEMENT ANALYSIS OF STABLE CRACK-GROWTH IN 3 SIZES OF COMPACT SPECIMENS OF A508-STEEL

Plane strain, elastic-plastic finite element analyses have been undert aken to simulate stable crack growth in an A508 forging steel for thre e different sizes of compact tension specimen and for small scale yiel ding by enforcing the same experimentally-measured deformation theory J resistance curve. The results show that path-dependence of the numer ically calculated J-integral occurs from the very beginning of crack g rowth, and the degree of path-dependence is not strongly related to th e amount of crack growth expressed as a proportion of the uncracked li gament. Crack tip stresses and strains are only mildly sensitive to ch anges in specimen size for the range of crack extension investigated. Small specimens appear to produce more intense deformation than small scale yielding and therefore cause more damage. For a tough steel such as A508 the parameter bsigma(f)/J(d) appears to be the most important in limiting the validity of J-characterized fields of deformation ahe ad of the growing crack.