Vibration Analysis of Carbon Fiber Reinforced Laminated Composite Skin with Glass Honeycomb Sandwich Beam Using HSDT

In this paper, the vibration analysis of uniform laminated composite sandwich beam with a viscoelastic core was studied. The governing equation of motion of the laminated composite sandwich beam has been derived based on higher order shear deformation theory (HSDT) in finite element model (FEM). The developed finite element model has been validated in terms of natural frequencies with the experimental values and the available literature. Various parametric studies have been performed to examine the impact of the core thickness, ply orientation and aspect ratio of the uniform laminated composite sandwich beam in response to free vibration for various boundary conditions. From the results it was concluded that that natural frequencies could be increased with increasing the core thickness and decreased with increasing the aspect ratio

Vibration analysis of multiwalled carbon nanotube-reinforced composite shell: An experimental study

In the present study, the vibration analysis of a multiwalled carbon nanotubes (MWCNTs)-reinforced composite shell is performed to investigate the enhancement in natural frequencies and damping of polymer composite structure. Initially, the material characterization of MWCNT-reinforced polymer resin was performed using scanning electron microscope, transmission electron microscope, and energy-dispersive X-ray analysis to identify the bonding behavior of MWCNT with resin, structure of MWCNTs, structural integrity, and chemical purity of MWCNT. The mechanical characterization of MWCNT-reinforced polymer composites was performed using universal testing machine to identify the enhancement in tensile properties of the composites with MWCNT reinforcement. Laminated composite shell samples were then fabricated with the different weight fraction of the MWCNT to study the effect of weight percentage of MWCNT on the composite shells on enhancement of natural frequencies and damping. Significant increase in tensile characteristics of the composites could also be identified with the addition of MWCNT in polymer composites. It was also observed that the fundamental natural frequency and damping factor of the hybrid composite could be increased by 20% and 7%, respectively, with 1 wt% reinforcement of MWCNT in the polymer resin. </jats:p

Vibration analysis of the multi-walled carbon nanotube reinforced doubly curved laminated composite shallow shell panels: An experimental and numerical study

In this study, free and forced vibration analysis of the multi-walled carbon nanotube reinforced doubly curved laminated composite shallow shell panels has been performed. The governing differential equation of motion of the doubly curved laminated composite shallow shell panel is formulated using higher order shear deformation theory with the Lagrangian approach. In a finite element formulation , the mathematical model is derived with a nine-node quadrilateral element considering seven degrees of freedom at each node. The efficiency of the present finite element model (FEM) is demonstrated and compared by validating the results with the available literature, and it is also compared with the experimental measurements of the cylindrical laminated composite shell panel with and without multi-walled carbon nanotube reinforcement. Material properties of the laminated composite structure with and without multi-walled carbon nanotube reinforcements are evaluated through the impulse excitation vibration test in accordance with the ASTM E1876-15. The influence of multi-walled carbon nanotube on the stiffness and structural integrity of the curved laminated composite shallow shell panels is also studied in terms of natural frequencies. Parametric analysis for the multi-walled carbon nanotube reinforced doubly curved laminated composite shallow panel is performed to study the influence of radius of curvature, shell geometry, thickness ratio, aspect ratio, stacking sequence, and the boundary conditions on structural performance. The forced vibration behavior of the curved composite shallow shell panel is studied with the different geometry configuration, and the influence of multi-walled carbon nanotube in the transverse vibration response is also studied. It has been concluded that the rigidity and structural performance of the doubly curved laminated composite shell panels are enhanced with the reinforcement of multi-walled carbon nanotube. </jats:p

Free and Forced Vibration Characteristics of CNT Reinforced Composite Spherical Sandwich Shell Panels with MR Elastomer Core

In this work, the dynamic behavior of the spherical magnetorheological elastomer (MRE) sandwich shell panel with multiwalled carbon nanotubes (MWCNT) reinforced composite face sheets is studied. The governing differential equation of motion for the (doubly curved) spherical sandwich shell panel is derived based on the Higher-Order Shear Deformation Theory (HSDT) kinematics. In the finite element framework, nine noded iso-parametric elements with nine Degrees of Freedom (DOFs) at each node are considered for solving the numerical problem. The finite element model of the multifunctional MR elastomer core spherical sandwich shell panel is validated against the existing works in terms of natural frequencies on different boundary conditions and magnetic field environment. The influence of MWCNT in the face sheet of the MR elastomer spherical sandwich shell panel is also studied through the structural rigidity. Detailed parametric investigations are performed to study the stiffness and damping characteristics of the shell panel with respect to the magnetic field intensities, thickness ratio, aspect ratio, ply orientation, and boundary conditions on the multifunctional MR elastomer core spherical sandwich shell panel. Also, the transverse vibration study of the MWCNT reinforced spherical sandwich shell with MR elastomer is carried out for different magnetic field intensities and curvatures to assess their effects on the structural performance. This study shows the applicability of the MR elastomer in sandwich shell structure for control of vibration and damping. </jats:p