FLEXURAL BEHAVIOR OF GENERAL LAMINATED COMPOSITE AND SANDWICH PLATES USING A SECANT FUNCTION BASED SHEAR DEFORMATION THEORY

Abstract

A SECANT FUNCTION BASED SHEAR DEFORMABLE FINITE ELEMENT MODEL IS DEVELOPED FOR THE FLEXURAL BEHAVIOR OF LAMINATED COMPOSITE AND SANDWICH PLATES WITH VARIOUS CONDITIONS. THE STRUCTURAL KINEMATICS OF THE PLATE IS EXPRESSED BY MEANS OF SECANT FUNCTION BASED SHEAR DEFORMATION THEORY NEWLY DEVELOPED BY THE AUTHORS. THE THEORY POSSESSES NON-LINEAR SHEAR DEFORMATION AND ALSO SATISFIES THE ZERO TRANSVERSE SHEAR CONDITIONS ON TOP AND BOTTOM SURFACES OF THE PLATE. THE FIELD VARIABLES ARE ELEGANTLY UTILIZED IN ORDER TO ENSURE C⁰ CONTINUITY REQUIREMENT. PENALTY PARAMETER IS IMPLEMENTED TO SECURE THE CONSTRAINTS ARISING DUE TO INDEPENDENT FIELD VARIABLES. A BIQUADRATIC QUADRILATERAL ELEMENT WITH EIGHT NODES AND 56 DEGREES OF FREEDOM IS EMPLOYED TO DISCRETIZE THE DOMAIN.  EXTENSIVE NUMERICAL TESTS FOR THE FLEXURAL BEHAVIOR OF LAMINATED COMPOSITE AND SANDWICH PLATES ARE CONDUCTED TO AFFIRM THE VALIDITY OF THE PRESENT FINITE ELEMENT MODEL IN CONJUNCTION WITH THE IMPROVED STRUCTURAL KINEMATICS. INFLUENCES OF BOUNDARY CONDITIONS, LOADING CONDITIONS, LAMINATION SEQUENCES, ASPECT RATIO, SPAN-THICKNESS RATIO, ETC ON THE FLEXURAL BEHAVIOR ARE INVESTIGATED SPECIFICALLY AND COMPARED WITH THE EXISTING RESULTS IN ORDER TO INDICATE THE PERFORMANCE OF THE PRESENT MATHEMATICAL TREATMENT.