AN EXPERIMENTAL AND ANALYTICAL STUDY OF THE TAYLOR IMPACT TEST

Taylor impact tests were performed using projectiles made from an alum inium-lithium alloy with a Hopkinson bar as the target so that load/ti me data could be recorded during the tests. The aluminium-lithium allo y was shown in separate dynamic compression tests using the Hopkinson bar to be reasonably strain rate insensitive. Analysis of the Taylor t est data using analytical methods, which only account for the compress ion work of the Taylor test, indicate a strain rate sensitivity of the material which is contrary to the independently obtained dynamic comp ression test results. The work of elastic compression of the target is evaluated using the experimental Hopkinson bar load/time data. The el astic and plastic shear work done on the projectile was also evaluated and these were shown to represent significant energy absorbing mechan isms which when added to the compressive Taylor work, account for the projectile impact kinetic energy. Anomalous strain rate sensitivity ef fects obtained from the Taylor tests are thereby explained. The sensit ivity of derived flow stress data to errors in measurement of length a pply to both analytical and two dimensional finite element solutions o f the Taylor impact problem, nevertheless the latter technique has the capability to generate projectile profile information as well as load /time data, permitting independent evaluation of constitutive properti es.