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Structural Engineering and Mechanics
  Volume 57, Number 2, January25 2016 , pages 239-63
DOI: https://doi.org/10.12989/sem.2016.57.2.239
 


Natural vibration of the three-layered solid sphere with middle layer made of FGM: three-dimensional approach
Surkay D. Akbarov, Hatam H. Guliyev and Nazmiye Yahnioglu

 
Abstract
    The paper studies the natural oscillation of the three-layered solid sphere with a middle layer made of Functionally Graded Material (FGM). It is assumed that the materials of the core and outer layer of the sphere are homogeneous and isotropic elastic. The three-dimensional exact equations and relations of linear elastodynamics are employed for the investigations. The discrete-analytical method proposed by the first author in his earlier works is applied for solution of the corresponding eigenvalue problem. It is assumed that the modulus of elasticity, Poisson\'s ratio and density of the middle-layer material vary continuously through the inward radial direction according to power law distribution. Numerical results on the natural frequencies related to the torsional and spheroidal oscillation modes are presented and discussed. In particular, it is established that the increase of the modulus of elasticity (mass density) in the inward radial direction causes an increase (a decrease) in the values of the natural frequencies.
 
Key Words
    functionally graded material; three-layered solid sphere; natural vibration; natural frequencies; torsional oscillation; spheroidal oscillation
 
Address
Surkay D. Akbarov: Department of Mechanical Engineering, Yildiz Technical University, Yildiz Campus,
34349, Besiktas, Istanbul, Turkey; Institute of Mathematics and Mechanics of the National Academy of Sciences of Azerbaijan, AZ1141, Baku, Azerbaijan
Hatam H. Guliyev: Institute of Geology and Geophysics of the National Academy of Sciences of Azerbaijan, AZ1073, Baku, Azerbaijan
Nazmiye Yahnioglu: Department of Mathematical Engineering, Yildiz Technical University, Davutpasa Campus, 34220, Esenler Istanbul, Turkey
 

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