ELASTO-PLASTIC STRESS ANALYSIS IN ROTATING DISKS AND PRESSURE VESSELS MADE OF FUNCTIONALLY GRADED MATERIALS

Abstract

A NEW ELASTIOÂPLASTIC STRESS SOLUTION IN AXISYMMETRIC PROBLEMS (ROTATING DISK, CYLINDRICAL AND SPHERICAL VESSEL) IS PRESENTED. THE ROTATING DISK (CYLINDRICAL AND SPHERICAL VESSEL) WAS MADE OF A CERAMIC/METAL FUNCTIONALLY GRADED MATERIAL, I.E. A PARTICLEÂREINFORCED COMPOSITE. IT WAS ASSUMED THAT THE MATERIALÂS PLASTIC DEFORMATION FOLLOWS AN ISOTROPIC STRAIN-HARDENING RULE BASED ON THE VON-MISES YIELD CRITERION. THE MECHANICAL PROPERTIES OF THE GRADED MATERIAL WERE MODELED BY THE MODIFIED RULE OF MIXTURES. BY ASSUMING SMALL STRAINS, HENCKYÂS STRESSÂSTRAIN RELATION WAS USED TO OBTAIN THE GOVERNING DIFFERENTIAL EQUATIONS FOR THE PLASTIC REGION. A NUMERICAL METHOD FOR SOLVING THOSE DIFFERENTIAL EQUATIONS WAS THEN PROPOSED THAT ENABLED THE PREDICTION OF STRESS STATE WITHIN THE STRUCTURE. SELECTED FINITE ELEMENT RESULTS WERE ALSO PRESENTED TO ESTABLISH SUPPORTING EVIDENCE FOR THE VALIDATION OF THE PROPOSED APPROACH.