Modernization of the VK-350 Instrumented Drop Weight Impact Testing Machine for Impact Testing of Various Types

Abstract

This study conducted modernization of the VK-350 instrumented drop weight impact testing machine (DWITM) developed at the Pisarenko Institute of Problems of Strength of the National Academy of Sciences of Ukraine, equipped with a high-speed strain and force recording system that allows recording a load diagram with a sampling rate of up to 20 MHz, and heating and cooling systems for testing specimens in a wide temperature range. Modernization was carried out to expand the functionality of the DWITM, namely, a new dynamometer and specimen fixing units for impact shear, compression and dynamic pushing tests were installed. The new dynamometer was calibrated for two ranges of amplification and test specimens of various types were tested. The DWITM was also equipped with a video recording system, which includes a high-speed PHOTRON FASTCAM NOVA S9 camera that allows recording the deformation and fracture process at a speed of up to 200,000 frames per second. The camera is equipped with a 12x zoom lens and stroboscopic high-frequency lamps for illumination with the GSVITEC MultiLED G8 control system. Based on the results of the impact bending and shear tests, video signals of the deformation and fracture of the specimens were obtained, which made it possible to determine the time of onset of plastic deformation and formation of adiabatic shear zones in the impact shear specimens, as well as the moment of crack appearance on the side surface of the Charpy specimen and to estimate the rate of its propagation.