LARGE STABLE CRACK-GROWTH IN FRACTURE-MECHANICS SPECIMENS

According to the J concept, information is reported about the crack re sistance behaviour up to 8 mm crack growth of side-grooved CT-25 as we ll as CCT-25 specimens made from German standard steel StE 460. Numeri cal simulations controlled by J(R) curves make the calculation of J fr om the stresses and strains of specimen models during large crack grow th feasible. These data allow a comparison to standards and rules desc ribing the evaluation of J from experiments. Using stress, strain and displacement fields from a plane-strain finite-element analysis, the e xtended J concept is discussed concerning larger ductile crack growth. Additionally, the distribution of other fracture mechanics parameters such as the crack tip opening displacement (CTOD) and the crack tip o pening angle (CTOA) are presented for larger crack growth.