A study on the impact measurement instrumentation for a bi-pendulum testing machine

Experimental investigations of structures under impact load are normally carried out by means of drop-weight testing rigs, which are often tailor-made, and require sensors for fast transient measurement of mechanical quantities (namely force, displacement, velocity and absorbed energy). Since these tests are quite expensive, time-consuming and often not repeatable, the sensors have to give reliable and interpretable results in the first test. In this paper a study on the instrumentation for impact measurements has been conducted, utilizing a bi-pendulum impact testing machine, which was realised at the Engineering Materials Laboratory of the University of Messina. Attention has been focused on the choice of the quantities to be measured, on the measurements problems, on the calibration of the instrumentation and on the mechanical characterization of the impact machine. A novel impact load cell, based on a piezo-film sensor, and able to measure directly on the specimen is also proposed. Some results on the dynamic crushing of a PS foam are presented and further developments on instrumentation design are outlined.