STABILITY AND NONLINEAR DYNAMIC BEHAVIOUR OF CROSS-PLY LAMINATED HEATED CYLINDRICAL SHELLS

Abstract

THE STABILITY OF POSTBUCKLED EQUILIBRIUM CONFIGURATIONS AND THE NONLINEAR DYNAMIC CHARACTERISTICS OF CROSS-PLY LAMINATED HEATED CYLINDRICAL SHELLS ARE INVESTIGATED EMPLOYING SEMIANALYTICAL SHELL ¯NITE ELEMENT. THE PRESENCE OF ASYMMETRIC PERTURBATION IN THE FORM OF SMALL MAGNITUDE LOAD SPATIALLY PROPORTIONAL TO THE LINEAR BUCKLING MODE SHAPE IS CONSIDERED TO INITIATE THE BIFURCATION OF THE SHELL DEFORMATION FROM AXISYMMETRIC MODE TO ASYMMETRIC ONE. THE FREQUENCIES OF SMALL OSCILLATIONS ABOUT EQUILIBRIUM CONFIGURATION ARE OBTAINED BY SOLVING THE EIGENVALUE PROBLEM FORMULATED USING TANGENT STIFFNESS MATRIX OF THE CONVERGED EQUILIBRIUM CON¯GURATION AND MASS MATRIX. THE STUDY REVEALS THAT THE PREDICTION OF THE POSTBUCKLING EQUILIBRIUM CON¯GURATION FROM NONLINEAR STATIC ANALYSIS DEPENDS ON THE NATURE (LONGITUDI-NALLY SYMMETRIC/ANTISYMMETRIC) OF INITIAL DISTURBANCE. THE LONGITUDINALLY ANTISYMMETRIC POSTBUCKLED EQUILIBRIUM CONFIGURATION IS STABLE WHEREAS THE LONGITUDINALLY SYMMETRIC ONE IS UNSTABLE. THE NONLINEAR DYNAMIC RESPONSE SHOWS THAT THE SHELL WITH LONGITUDINALLY SYMMETRIC DISTURBANCE JUMPS FROM SYMMETRIC MODE TO ANTISYMMETRIC MODE AND THE PREDICTED EQUILIBRIUM CON¯GURATION IS OF ANTISYMMETRIC NATURE IRESPECTIVE OF THE TYPE OF INITIAL DISTURBANCE. THE NONLINEAR FORCED DYNAMIC RESPONSE OF THE HEATED SHELL IN THE PREBUCKLING REGION DIFFERS SIGNIFICANTLY FROM THAT IN THE POSTBUCKLING REGION.