Estimating dynamic ultimate tensile strength from instrumented Charpy data

Instrumented Charpy test data have often been used to obtain estimates of various mechanical properties under elevated loading rates, such as dynamic yield properties. A widely used relationship between Charpy general yield force and dynamic yield strength was originally proposed by Server in 1978. This same relationship, however, cannot be used for estimating the dynamic (ultimate) tensile strength from the Charpy maximum force, since it relies on the ratio between shear and tensile stress, which at general yield is different than at maximum force. In the study described in this paper, we modified Server's relationship in order to obtain reliable, and possibly conservative, estimates of dynamic ultimate tensile strength from the maximum force measured in an instrumented Charpy test. Once more experimental data has been accumulated, the results of this investigation might have significant implications for the revision of fracture mechanics test standards which utilize dynamic ultimate tensile properties for the qualification/validation of fracture toughness tests conducted at elevated loading rates. (C) 2016 Elsevier Ltd. All rights reserved.