Calibration of a Hopkinson Bar with a Transfer Standard

Abstract

A program requirement for field test temperatures that are beyond the test accelerometer operational limits of −30° F and +150° F required the calibration of accelerometers at high shock levels and at the temperature extremes of −50° F and +160° F. The purposes of these calibrations were to insure that the accelerometers operated at the field test temperatures and to provide an accelerometer sensitivity at each test temperature. Because there is no National Institute of Standards and Technology traceable calibration capability at shock levels of 5,000–15,000 g for the temperature extremes of −50° F and +160° F, a method for calibrating and certifying the Hopkinson bar with a transfer standard was developed. Time domain and frequency domain results are given that characterize the Hopkinson bar. The National Institute of Standards and Technology traceable accuracy for the standard accelerometer in shock is ±5%. The Hopkinson bar has been certified with an uncertainty of 6%.