GEOMETRICALLY NONLINEAR STATIC AND
DYNAMIC ANALYSIS OF PIEZOELECTRIC FIBER
REINFORCED COMPOSITE PLATES AND SHELLS


Abstract:

In the present research work, geometrically nonlinear static and dynamicsponse control of laminated composite plates and shells are investigated with and without hygrothermal environment employing piezoelectric fiber reinforced composite (Active fiber composites (AFC)/ Macro fiber composite (MFC)) lamina as a actuator. Performances of piezoelectric fiber reinforced composite actuator to control the nonlinear responses of composite plates and shells under combined mechanical and hygrothermal environment are investigated.


Laminated composite plates and shells are being widely used in aeronautical, mechanical, civil, chemical and other industries over the past three decades. The main reasons for this trend are outstanding mechanical properties of composites, such as high strength to weight ratio, excellent corrosion resistance etc. The laminated composites have ability to allow the structural properties to be tailored according to requirements adds to their versatility for sensitive applications. Composite structures in the form of plates and shells are used in almost all structural components of aircraft structures and launch vehicles, in addition to the specific use in wings, fuselages, artillery rocket nose cone, thermal shielding of space vehicles, reactor vessels, turbines, heat exchanger tubes, heat-engine components, electronic goods. All these components are susceptible to failure from large deflections, vibrations or excessive stresses induced by hygrothermal or combined hygral-thermo-mechanical loading leading to serious deterioration of the structural performance. Thus it is necessary to investigate the static and dynamic behaviour of plates and shells including geometric non-linearity.


The development of intelligent composite materials with piezoelectric components offers great potential for use in advanced aerospace structural applications. The coupled electromechanical properties of piezoelectric ceramics and their availability in the form of thin sheets make them well suited for use as distributed sensors and actuators for controlling structural response. In the present study the synthetic piezoelectric fiber reinforced composites (PFRC): AFC/MFC are used as an actuator which is more effective and adaptive compared to conventional monolithic PVDF/PZT.


In the present study, finite element method is used to obtain the governing differential equation of the smart composite structure. The finite element model incorporates the first order shear deformation theory and von Krmn type geometric nonlinearity with thermo-electro-elastic coupling effects. The incremental iterative procedure is implemented for the solution of nonlinear equilibrium equations. In the present study nonlinear equilibrium equations are linearised by using Newton-Raphson iterative method. The nonlinear time dependent equations are solved using the Newmark time integration in association with Newton-Raphson iterative method. Negative velocity feedback control algorithm is used to control the dynamic response of the smart laminated composite plates and shells.


The developed finite element procedures are coded in C language and the acuracy of the present formulation is established from the good agreement of the authors results with those available in the published literature for the linear and nonlinear static and transient analyses of laminated composite plates and shells with/without piezoelectric layers. Using present finite element model, geometrically nonlinear static and dynamic behaviour of composite plates and shells integrated with piezoelectric fiber reinforced composite (AFC/MFC) layers isvestigated. Performance of piezoelectric fiber reinforced composite (AFC/MFC) actuator to control nonlinear responses of plates and shells subjected to mechanical loading with and with out hygrothermal environment are studied.


The numerical examples of laminated plates and shells are presented to show the effects of different load cases, boundary conditions and several geometric and material parameters on the nonlinear bending and transient response. Additional numerical examples are presented to show the effect of load, boundary conditions, geometric and material parameters on performance of piezoelectric fiber reinforced actuator to control nonlinear bending and transient responses of plates and shells. Furthermore, numerical examples are presented to assess the performance of piezoelectric fiber reinforced actuator to control nonlinear bending and transient responses of plates and shells under hygrothermal environment. From the numerical results, it is concluded that, piezoelectric fiber reinforced composite actuator (MFC/AFC) with appropriate piezoelectric fiber orientation effectively control the nonlinear static and dynamic responses of laminated composite plates and shells.


Key words: Geometric Nonlinear, Negative velocity feedback, Hygrothermal, Actuator, Sensor, Vibration, Laminated composite, Plate, Shell, Finite element method, PVDF, Active Fiber Composites, Macro Fiber Composites.