Separation and rebuilding of waves in elastic and viscoelastic bars using redundant measures

When using a classical SHPB (Split Hopkinson Pressure Bar) set-lip, the use ful measuring time is limited by the need of separating the waves propagati ng in opposite directions. A new Method for separating and rebuilding waves in finite bars was developed, with no time limit, from N strain measuremen ts and P particle velocity measurements (N + P greater than or equal to 2). It takes account of the wave dispersion in elastic and viscoelastic bars; The method is illustrated with the loading of a free bar where the measured displacement is 30 times longer than the displacement that would be obtain ed with the classical method. (C) 2001 Academic des sciences/Editions scien tifiques et medicales Elsevier SAS.