AN EFFICIENT COUPLED POLYNOMIAL INTERPOLATION SCHEME FOR SHEAR MODE SANDWICH BEAM FINITE ELEMENT

Abstract

AN EFFICIENT PIEZOELECTRIC SANDWICH BEAM FINITE ELEMENT IS PRESENTED HERE. IT EMPLOYS THE COUPLED POLYNOMIAL FIELD INTERPOLATION SCHEME FOR FIELD VARIABLES WHICH INCORPORATES ELECTROMECHANICAL COUPLING AT INTERPOLATION LEVEL ITSELF; UNLIKE CONVENTIONAL SANDWICH BEAM THEORY (SBT) BASED FORMULATIONS AVAILABLE IN THE LITERATURE. VARIATIONAL FORMULATION IS USED TO DERIVE THE GOVERNING EQUATIONS, WHICH ARE USED TO ESTABLISH THE RELATIONSHIP BETWEEN FIELD VARIABLES. THESE RELATIONS LEAD TO THE COUPLED POLYNOMIAL FIELD DESCRIPTIONS OF VARIABLES UNLIKE CONVENTIONAL SBT FORMULATIONS WHICH USE ASSUMED INDEPENDENT POLYNOMIALS. THE RELATIVE AXIAL DISPLACEMENT IS EXPRESSED ONLY BY COUPLED TERMS CONTAINING CONTRIBUTIONS FROM OTHER MECHANICAL AND ELECTRICAL VARIABLES, THUS ELIMINATING USE OF TRANSVERSE DISPLACEMENT DERIVATIVE AS DEGREE OF FREEDOM. A SET OF COUPLED SHAPE FUNCTION BASED ON THESE POLYNOMIALS HAS SHOWN THE IMPROVEMENT IN THE CONVERGENCE CHARACTERISTICS OF THE SBT BASED FORMULATION. THIS IMPROVEMENT IN PERFORMANCE IS ACHIEVED WITH ONE NODAL DEGREE OF FREEDOM LESSER THAN THE CONVENTIONAL SBT FORMULATIONS.