DYNAMIC FINITE-ELEMENT MODELING OF THE EFFECTS OF SIZE ON THE UPPER SHELF ENERGY OF PRESSURE-VESSEL STEELS

Dynamic finite element modeling (FEM) of the fracture behavior of fati gue-precracked Charpy specimens was performed to determine the effect of single variable changes in ligament size, width, span, and thicknes s on the upper shelf energy. A tensile fracture-strain based method fo r modeling crack initiation and propagation was used, It was found tha t the upper shelf energy of precracked specimens (USE(p)) is proportio nal to b '', where b is ligament size and n varies from about 1.6 for subsize to 1.9 for full size specimens. The USE(p) was found to be pro portional to (width)(2.5). The dependence on span was found to be non- linear. The dependence on thickness was found to be linear fur all cas es studied. Some of the data from the FEM analysis were compared with experimental data and were found to be in reasonable agreement.