Evaluation of dynamic response of a femur sensor using impact

摘要

Dynamic response of a femur sensor, which is used for dummies in automobile crash tests, is evaluated by applying the split Hopkinson pressure bar technique or the Kolsky's apparatus. Elastic wave pulses propagating in thin circular bars impart an impulsive input of 10 kN in peak amplitude and 0.7 ms in duration time to the femur sensor placed between the two bars. Dynamic force acting on both sides of the sen- sor in the axial direction is determined by the measurement of the incident, reflected and transmitted pulses in the bars using strain gauges. The strain gauges on the bars are calibrated in advance using a laser interfer- ometer. It was found that the sensitivity of the sensor is flat and the phase lag is quite small up to 3.9 kHz, that the first resonance takes place at 9.8 kHz, and that the cross-talk output is ±3～4 of the axial input.