A telemetry-based device to determine the force-displacement behaviour of materials in high impact loading situations

Meaningful testing of stab resistant body armour requires the use of realis tic body tissue simulants. A device for the determination of the force-disp lacement behaviour of materials in high impact loading situations has been developed for the testing of such simulants. Force measurement is achieved with the use of electrical foil strain gauges applied to a cylindrical load cell. A piezo-resistive accelerometer ( +/- 500 g) is used to calculate th e displacement of the device through double integration of its signal, with the impact velocity used as a boundary condition. The signals from the str ain gauge circuit and the accelerometer are sampled at 2500 Hz. The data ar t transmitted to a receiver via telemetry using a 418 MHz FM transmitter an d from the receiver to a laptop PC via the serial port. Calibration of the device is described and sample results showing forces up to 2500 N and disp lacements up to 0.04 m are presented. (C) 2000 Elsevier Science Ltd. All ri ghts reserved.