FAILURE MECHANISMS IN COMPOSITE TURBINE BLADES

BECAUSE OF THE COMPLEXITY OF GEOMETRY, LOADS AND MATERIAL SYSTEMS OF TURBINE BLADES, THE STRESS AND STRENGTH CHARACTERISTICS CAN NOT BE ACCURATELY PREDICTED BY EXISTING METHODS. THE COMPOSITE TURBINE BLADE STRENGTH CAPABILITIES ARE VERY MUCH DEPENDENT UPON THE CONSTITUENT MATERIAL PROPERTIES, PLY ORIENTATIONS AND STACKING SEQUENCE. THE OBJECTIVE OF THE PROPOSED STUDY IS TO DEVELOP A TECHNIQUE TO PREDICT THE DIFFERENT FAILURE MODES IN THE COMPOSITE TURBINE BLADE. THE EFFECT OF STACKING SEQUENCE, PLY ORIENTATIONS, CENTRIFUGAL FORCE AND AIR PRESSURE ON THE FAILURE OF TURBINE BLADES WILL BE STUDIED. THE SOLUTION TO THE BOUNDARY VALUE PROBLEM WILL BE OBTAINED BY USING LINEAR ELASTICITY EQUILIBRIUM AND CONSTITUTIVE RELATIONS. EACH LAYER WILL BE MODELED SEPARATELY. THE USE WILL BE MADE OF THE EXPERIENCE GAINED IN THE EXTENSIVE RESEARCH WORK DONE ON INPLANE AND INTERLAMINAR FAILURE MODES. THE PROPOSED STUDY WILL REVEAL INTERESTING FEATURES OF TURBINE BLADES. SOME PRELIMINARY WORK DONE ON THE PROBLEM ON THE BASIS OF NEW APPROACH ARE GIVEN IN THE PROPOSAL. IN THIS STUDY, ALL THE STRESS COMPONENTS (SIX) WILL BE CALCULATED AND USED IN THE STRENGTH PREDICTIONS.