Experimental Assessment of the Equivalent Strain Rate for an Instrumented Charpy Test.

Instrumented Charpy test data can be used to obtain estimates of dynamic yield strength, by means of a well-established relationship published by W. Server in 1978. A fundamental issue in comparing measured dynamic tensile properties and Charpy-based estimations is establishing the equivalent uniaxial strain rate for an instrumented Charpy test, typically conducted at ≈ 5.5 m/s. In this investigation, by performing tensile tests at various strain rates and instrumented Charpy tests for 10 different materials, we compared values of dynamic yield strength both measured from tensile tests and estimated by means of Server's equation. The obtained equivalent Charpy strain rates were found to vary significantly from material to material, and to correlate reasonably with specific values of absorbed energy measured during the impact tests.