Standard Test Method for Instrumented Impact Testing of Metallic Materials

5.1 Instrumented impact testing provides an independent measurement of the total absorbed energy associated with fracturing CVN or MCVN specimens for test machines equipped with a dial and/or optical encoder.

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 energy.

5.3 In addition to providing an measure of total absorbed energy (W_t), instrumented testing enables the determination of characteristic force, energy, and displacement parameters. Depending on the material and test temperature, these parameters can provide very useful information (in addition to total absorbed energy) on the fracture behavior of materials such as: the temperature which corresponds to the onset of the lower shelf; the temperature which corresponds to the onset of the upper shelf; the pre-maximum force energy (W_m); the post-maximum force energy; the energy associated with shear lip tearing after brittle fracture; the general yield force (F_gy); the force at brittle fracture initiation (F_bf); the arrest force (F_a). The instrumented data may also be used to highlight test results which should be discarded on the basis of misalignment or other critical test factors.