Design and application of an instrumented projectile for load measurements during impact

摘要

No standardised device is available yet to measure contact forces continuously during transverse impacts caused by a projectile on a metal plate or a thin-walled structure. This study describes the design and validation phases of an instrumented projectile (mass = 1 kg) that can be used to achieve such measurements. The impact force, indeed, is computed from the strain data collected by some strain gauges glued on to a projectile part, which remains elastic during shock. Under numerically defined conditions, the projectile geometry makes it possible to record signals that are not disturbed by the reflections of the compressive and tensile strength waves appearing inside the projectile during and after shock. Gauge signal post-filtering is then virtually useless. The strain gauge-instrumented projectile sensitivity is used to study the effects of small clamping pressure variations during the transverse impact study on shipbuilding steel plates. A second application deals with the impact of an automotive steel dome initially drawn with a bulge test apparatus.