Computer simulation of the Charpy V-notch toughness test

The impact of a striker with the ASTM Type A Charpy V-Notch specimen has been calculated. An elastic-plastic constitutive law with J2-flow theory and isotropic hardening was used to model A-533 Grade B class 1 steel at 1000C. Large strain and rotation are accounted for. It was found that the notch stress-strain state was independent of the three-point loading type (round- or flat-tip striker or pressure push) and was most strongly correlated with notch-opening displacement. The dynamic stress-strain state at the time of fracture initiation was obtained by comparing the calculated deformed shape with that obtained in interrupted Charpy-V-notch tests where cracking had started. This time agreed with a computed prediction of fracture initiation obtained using a computer model of material damage. Cracking starts at the notch at about 40% of the maximum load found in an instrumented Charpy test. The distribution and partition of specimen energy has also been calculated. Adiabatic heating and strain rate are discussed. (author)