Standard Test Method for Instrumented Impact Testing of Metallic Materials

Abstract

5.1 Instrumented impact testing provides an independent measurement of the absorbed energy associated with fracturing CVN or MCVN specimens for test machines equipped with a dial or optical encoder, or both. 5.2 Instrumented impact testing is particularly effective in MCVN testing, since the resolution of a calibrated strain-gaged striker does not necessarily decrease with the magnitude of the measured force. 5.3 In addition to providing a measure of instrumented absorbed energy (Wt), instrumented testing enables the determination of characteristic force, partial instrumented absorbed energy, and displacement parameters. Depending on the material and test temperature, these parameters can provide useful information (in addition to instrumented absorbed energy) on the fracture behavior of materials such as: the temperature that corresponds to the onset of the lower shelf; the temperature that corresponds to the onset of the upper shelf; partial instrumented absorbed energy up to maximum force (Wm); partial instrumented absorbed energy up to the force at brittle fracture initiation (Wbf); partial instrumented absorbed energy after maximum force (Wt–Wm); general yield force (Fgy); force at brittle fracture initiation (Fbf); arrest force (Fa). The instrumented data may also be used to highlight test results that should be discarded on the basis of misalignment or other critical test factors.