Instrumentation and preliminary evaluation of a drop tower tester for low and medium impact energy

Soft, porous structures imbibed with liquids have good impact attenuation properties. Literature survey reveals a continuous need for new impact tests to assess impact response for the newly developed soft, porous materials. This paper presents a versatile drop tower tester which is based on an impactor that slides inside a transparent tube. The test rig is equipped with high-speed transducers (force and acceleration) and a laser system used to measure the deformation of the experimental cell. A high-speed camera records subtle details of the impact that are not are visible with the naked eye. Preliminary experiments made on dry and imbibed soft fibrous tridimensional textile have shown good repeatability during impact. The experiments presented validate the experimental procedure, based on the analysis of the contact force-displacement curve, acceleration, and impact force-transmitted force. The obtained results demonstrate that true impact response is described with high resolution.