EVALUATION OF ELASTO-PLASTIC STRESSES ON A STRAIN HARDENING MATERIAL USING MOIRE INTERFEROMETRY

Moire interferometry is a recent optical technique, which combines the concepts and techniques of geometrical moire and optical interferometry and enables fill-field measurements with high sensitivity. Using this technique, elasto-plastic strains were measured around a central circular hole in an aluminum plate subjected to uniaxial tension. Incremental load was applied and in-plane displacement fields were recorded at each load step. Elasto-plastic stresses were determined using incremental flow theory for strain hardening case and the elasto-plastic strain and stress destribution were plotted. A numerical solution for this problem was also obtained. Reliability of the measurements was ensured from the verification of equilibrium condition and close comparison of experimental values with numerical results.