Vibro-acoustic behavior of functionally graded carbon nanotube reinforced polymer nanocomposite plates

2016 ◽  
Vol 232 (7) ◽  
pp. 566-581 ◽  
Author(s):  
Nivish George ◽  
Jeyaraj Pitchaimani ◽  
SM Murigendrappa ◽  
MC Lenin Babu
Keyword(s):  
Carbon Nanotube ◽  
Polymer Nanocomposite ◽  
Functionally Graded ◽  
Mode Shapes ◽  
Integral Parameter ◽  
Acoustic Behavior ◽  
Acoustic Response ◽  
Resonant Amplitude ◽  
Reinforced Polymer ◽  
Vibration And Sound Radiation

This paper presents the numerical investigation results carried out on vibro-acoustic behavior of functionally graded carbon nanotube reinforced polymer nanocomposite plate using combined finite element method and Rayleigh integral. Parameter studies are carried out to analyze the influence of nature of functional grading, loading of carbon nanotube, and structural boundary conditions on free and forced vibration and sound radiation characteristics in detail. It is found that natural frequencies are significantly influenced by the nature of functional grading while the mode shapes are insensitive. The resonant amplitude of vibration and acoustic response are significantly influenced with the nature of different functional grading. This reflects in the bandwise calculation of sound power also which recommends the carbon nanotube functional grading with X distribution along the thickness direction for lower frequency level. Similar variation in vibro-acoustic response has been observed with increase in the carbon nanotube loading also.

Buckling and Free Vibration of Nonuniformly Heated Functionally Graded Carbon Nanotube Reinforced Polymer Composite Plate

2017 ◽  
Vol 17 (06) ◽  
pp. 1750064 ◽  
Author(s):  
Nivish George ◽  
P. Jeyaraj ◽  
S. M. Murigendrappa
Keyword(s):  
Temperature Field ◽  
Carbon Nanotube ◽  
Free Vibration ◽  
Composite Plate ◽  
Natural Frequencies ◽  
Vibration Mode ◽  
Functionally Graded ◽  
Temperature Fields ◽  
Mode Shapes ◽  
Reinforced Polymer

Buckling and free vibration behavior of functionally graded carbon nanotube reinforced polymer composite plate subjected to nonuniform temperature fields have been investigated using finite element approach. The effective material constants of the plate are obtained using the extended rule of mixture along with efficiency parameters of the carbon nanotube (to include geometry-dependent material properties). Influence of boundary conditions, aspect ratio, functional grading of the carbon nanotube, nonuniform thermal loading on thermal buckling and free vibration behavior of the heated plate are analyzed. It is observed that temperature fields and functional grading are influenced on the critical buckling temperature of the plates. Further, nature of functional grading showed significant change in buckling mode shapes irrespective of the boundary conditions. The first few natural frequencies of the plate under thermal load decreases as the temperature increases and they are influenced significantly by the nature of temperature field. Variations in free vibration mode shapes of the square plates found with not significant change as temperature increases. However, free vibration modes of the rectangular plates are sensitive to the nature of temperature field whenever there is a free edge associated with the boundary condition. Influence of functional grading on the free vibration mode shapes is not significant in contrast with the free vibration natural frequencies. The magnitude of free vibration natural frequencies of functional grade-X type carbon nanotube reinforcement showed higher in comparison with other two types of reinforcements considered here.

A Comprehensive Analysis on the Structural–Acoustic Aspects of Various Functionally Graded Plates

2015 ◽  
Vol 07 (05) ◽  
pp. 1550072 ◽  
Author(s):  
N. Chandra ◽  
S. Raja ◽  
K. V. N. Gopal
Keyword(s):  
Power Law ◽  
Volume Fraction ◽  
Transmission Loss ◽  
Sound Radiation ◽  
Functionally Graded ◽  
Radiation Efficiency ◽  
Sound Power ◽  
Acoustic Behavior ◽  
Acoustic Response ◽  
Plate Velocity

The vibration, sound radiation and transmission characteristics of plates with various functionally graded materials (FGM) are explored and a detailed investigation is presented on the influence of specific material properties on structural–acoustic behavior. An improved model based on a simplified first order shear deformation theory along with a near-field elemental radiator approach is used to predict the radiated acoustic field associated with a given vibration and acoustic excitation. Various ceramic materials suitable for engineering applications are considered with aluminum as the base metal. A power law is used for the volume fraction distribution of the two constitutive materials and the effective modulus is obtained using the Mori–Tanaka homogenization scheme. The structural–acoustic response of these FGM plates is presented in terms of the plate velocity, radiated sound power, sound radiation efficiency for point and uniformly distributed load cases. Increase in both vibration and acoustic response with increase in power law index is observed for the lower order modes. The vibro–acoustic metrics such as root-mean-squared plate velocity, overall sound power, frequency averaged radiation efficiency and transmission loss, are used to rank these materials for vibro–acoustically efficient combination. Detailed analysis has been made on the factors influencing the structural–acoustic behavior of various FGM plates and relative ranking of particular ceramic/metal combinations.

Free vibration response of carbon nanotube reinforced pretwisted conical shell under thermal environment

2019 ◽  
Vol 234 (3) ◽  
pp. 770-783 ◽  
Author(s):  
Pabitra Maji ◽  
Mrutyunjay Rout ◽  
Amit Karmakar
Keyword(s):  
Carbon Nanotubes ◽  
Finite Element ◽  
Carbon Nanotube ◽  
Free Vibration ◽  
Conical Shell ◽  
Dynamic Equilibrium ◽  
Thermal Environment ◽  
Shear Deformation Theory ◽  
Functionally Graded ◽  
Mode Shapes

Finite element procedure is employed to analyze the free vibration characteristics of rotating functionally graded carbon nanotubes reinforced composite conical shell with pretwist under the thermal environment. In this paper, four types of carbon nanotube grading are considered, wherein the distribution of carbon nanotubes are made through the thickness direction of the conical shell. An eight-noded isoparametric shell element is used in the present formulation to model the panel based on the first-order shear deformation theory. For moderate rotational speeds, the generalized dynamic equilibrium equation is derived from Lagrange’s equation of motion, neglecting the Coriolis effect. The finite element code is developed to investigate the effect of twist angle, temperature, aspect ratio, and rotational speed on natural frequencies. The mode shapes of a carbon nanotube reinforced functionally graded conical shell at different twist angles and rotational speeds are also presented.

scholarly journals Free Vibration Analysis of Laminated Functionally Graded Carbon Nanotube-Reinforced Composite Doubly Curved Shallow Shell Panels Using a New Four-Variable Refined Theory

2019 ◽  
Vol 3 (4) ◽  
pp. 104 ◽  
Author(s):  
Vu Van Tham ◽  
Tran Huu Quoc ◽  
Tran Minh Tu
Keyword(s):  
Carbon Nanotube ◽  
Free Vibration ◽  
Vibration Analysis ◽  
Shallow Shell ◽  
Free Vibration Analysis ◽  
Functionally Graded ◽  
Mode Shapes ◽  
Refined Theory ◽  
Reinforced Composite ◽  
Doubly Curved

In this paper, a new four-variable refined shell theory is developed for free vibration analysis of multi-layered functionally graded carbon nanotube-reinforced composite (FG-CNTRC) doubly curved shallow shell panels. The theory has only four unknowns and satisfies zero stress conditions at the free surfaces without correction factor. Five different types of carbon nanotube (CNTs) distribution through the thickness of each FG-CNT layer are considered. Governing equations of simply supported doubly curved FG-CNTRC panels are derived from Hamilton’s principle. The resultant eigenvalue system is solved to obtain the frequencies and mode shapes of the anti-symmetric cross-ply laminated panels by using the Navier solution. The numerical results in the comparison examples have proved the accuracy and efficiency of the developed model. Detailed parametric studies have been carried out to reveal the influences of CNTs volume fraction, CNTs distribution, CNTs orientation, dimension ratios and curvature on the free vibration responses of the doubly curved laminated FG-CNTRC panels.

Functionalized carbon nanotube reinforced polymer nanocomposite microcapsules with enhanced stiffness

2018 ◽  
Vol 550 ◽  
pp. 82-89 ◽  
Author(s):  
Siddheshwar B. Jagtap ◽  
Vishal D. Patil ◽  
Karthika Suresh ◽  
Farsa Ram ◽  
Muthu Subramanian Mohan ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Polymer Nanocomposite ◽  
Reinforced Polymer ◽  
Functionalized Carbon Nanotube

Crack growth analysis of carbon nanotube reinforced polymer nanocomposite using extended finite element method

2018 ◽  
Vol 233 (5) ◽  
pp. 1750-1770 ◽  
Author(s):  
Alok Negi ◽  
Gagandeep Bhardwaj ◽  
JS Saini ◽  
Neeraj Grover
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Carbon Nanotube ◽  
Crack Growth ◽  
Growth Analysis ◽  
Extended Finite Element Method ◽  
Polymer Nanocomposite ◽  
Extended Finite Element ◽  
Reinforced Polymer ◽  
Element Method

In this work, the crack growth analysis of carbon nanotube reinforced polymer nanocomposite has been performed using extended finite element method. The equivalent properties such as elastic modulus, Poisson’s ratio, fracture energy, and fracture toughness of the polymer nanocomposites have been evaluated by varying the percentage of carbon nanotube in terms of weight (both single-walled carbon nanotube and multi-walled carbon nanotube) in the polymer matrix. The elastic modulus of the polymer nanocomposite has been evaluated using modified Halpin–Tsai equation. The fracture energy of the polymer nanocomposite has been computed considering carbon nanotube pull-out and carbon nanotube debonding as the main toughening criterion. In the extended finite element method, the crack faces are modeled by discontinuous Heaviside jump functions, whereas the singularity in the stress field at the crack tip is modeled by crack tip enrichment functions. The value of stress intensity factor is evaluated using the domain form of interaction integral. The level set method has been used to track the crack growth. The numerical examples with an edge and a center crack in the polymer nanocomposite are analyzed and the influence of various parameters such as percentage of carbon nanotube and the aspect ratio on stress intensity factor are observed.

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