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Elastic analysis of polymeric cylinders reinforced with carbon nanotubes

Hosseini H., Kolahchi R., Heydari M.

Journal of Applied Mathematics and Computational Mechanics

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2016

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Vol. 15, nr 2

31--39

EN

In this work, stress analysis of a polymeric cylinder’s cylindrical shell reinforced with carbon nanotubes (CNTs) is investigated. The cylinder is subjected to mechanical and thermal loadings. All the equivalent mechanical and thermal properties of nano-composite cylinder are obtained using Mori-Tanaka model. Based on equilibrium, the governing equation is derived. Using an exact solution, the stresses and radial displacement distributions in the structure are calculated. The effects of CNTs volume percent on the stresses and radial displacement for internal and external pressure cylinder are the main discussion of this study. Numerical results indicate that with increasing CNTs volume percent, the stresses decrease. However, this shows the important effect of nanotechnology in stress reduction of cylinder which may be useful in sensors and actuators.

2

Continuous model for flexural vibration analysis of a Timoshenko cracked beam

Heydari M., Ebrahimi A., Behzad M.

Archives of Mechanics

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2013

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Vol. 65, nr 4

265–-288

EN

In this paper, a continuous model for vibration analysis of a beam with an open edge crack including the effects of shear deformation and rotary inertia is presented. A displacement field is suggested for the beam and the strain, and stress fields are calculated. The governing equation of motion for the beam has been obtained using Hamilton’s principle. The equation of motion is solved with a modified Galerkin method and the natural frequencies and mode shapes are obtained. A good agreement has been observed between the results of this research and the results of previous work done in this fiels. The results are also compared to results of a similar model with Euler-Bernoulli assumptions to confirm the advantages of the proposed model in the case of short beams.

3

An ellipsoidal model for studying response of head impacts

Heydari M., Jani S.

Acta of Bioengineering and Biomechanics

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2010

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Vol. 12, no. 1

47-53

EN

The objective of this study was to propose a new analytical model for studying response of head impacts. Head is modeled by fluidfilled ellipsoidal shell of inconstant thickness impacted by a solid elastic sphere. Modeling the head as an ellipsoid is more realistic than modeling it as a sphere, the previous model existing in the literature [3]–[8]. In this model, the effect of Hertzian contact stiffness and local shell stiffness are combined to derive explicit equations for impact duration, the peak force transmitted to head, and the head injury criterion. One of the advantages of the model presented is sensitivity to the site of impact. A comparison between the present analytical results with the analytical data from spherical model [8] has been done to verify the validation of the present model.