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Applied Mathematics and Mechanics(English Edition) 2013年第4期34卷 437-456页

作者： k.daneshjou M.TALEBITOOTI R.TALEBITOOTI School of Mechanical Engineering Iran University of Science and Technology School of Automotive Engineering Iran University of Science and Technology

The generalized differential quadrature method （GDQM） is employed to con- sider the free vibration and critical speed of moderately thick rotating laminated compos- ite conical shells with different boundary conditions developed from the first-order shear deformation theory （FSDT）. The equations of motion are obtained applying Hamilton＇s concept, which contain the influence of the centrifugal force, the Coriolis acceleration, and the preliminary hoop stress. In addition, the axial load is applied to the conical shell as a ratio of the global critical buckling load. The governing partial differential equations are given in the expressions of five components of displacement related to the points ly- ing on the reference surface of the shell. Afterward, the governing differential equations are converted into a group of algebraic equations by using the GDQM. The outcomes are achieved considering the effects of stacking sequences, thickness of the shell, rotating velocities, half-vertex cone angle, and boundary conditions. Furthermore, the outcomes indicate that the rate of the convergence of frequencies is swift, and the numerical tech- nique is superior stable. Three comparisons between the selected outcomes and those of other research are accomplished, and excellent agreement is achieved.

关键词： generalized differential quadrature method (GDQM) natural frequency,rotating conical shell first-order shear deformation theory (FSDT) critical speed

Wave transmission through laminated composite double-walled cylindrical shell lined with porous materials

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Applied Mathematics and Mechanics(English Edition) 2011年第6期32卷 701-718页

作者： k.daneshjou H.RAMEZANI R.TALEBITOOTI Department of Mechanical Engineering Iran University of Science and Technology Department of Automotive Engineering Iran University of Science and Technology

A study on free harmonic wave propagation in a double-walled cylindrical shell, whose walls sandwich a layer of porous materials, is presented within the framework of the classic theory for laminated composite shells. One of the most effective components of the wave propagation through the porous core is estimated with the aid of a flat panel with the same geometrical properties. By considering the effective wave component, the porous layer is modeled as a fluid with equivalent properties. Thus, the model is simplified as a double-walled cylindrical shell trapping the fluid media. Finally, the transmission loss （TL） of the structure is estimated in a broadband frequency, and then the results are compared.

关键词： transmission loss porous media cylindrical laminated composite shell

Long-term effects of main-body's obliquity on satellite formation perturbed by third-body gravity in elliptical and inclined orbit

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Research in Astronomy and Astrophysics 2017年第4期17卷 81-96页

作者： Majid Bakhtiari kamran daneshjou Mahdi Fakoor Department of Mechanical Engineering Iran University of Science and Technology Department of Aerospace Engineering Faculty of New Sciences and TechnologiesUniversity of Tehran

A new non-simplified model of formation flying is derived in the presence of an oblate main- body and third-body perturbation. In the proposed model, considering the perturbation of the third- body in an inclined orbit, the effect of obliquity （axial tilt） of the main-body is becoming important and has been propounded in the absolute motion of a reference satellite and the relative motion of a follower satellite. From a new point of view, J2 perturbed relative motion equations and considering a disturbing body in an elliptic inclined three dimensional orbit, are derived using Lagrangian mechanics based on accurate introduced perturbed reference satellite motion. To validate the accuracy of the model presented in this study, an auxiliary model was constructed as the Main-body Center based Relative Motion （MCRM） model. Finally, the importance of the main-body＇s obliquity is demonstrated by several examples related to the Earth-Moon system in relative motion and lunar satellite formation keeping. The main-body＇s obliquity has a remarkable effect on formation keeping in the examined in-track and projected circular orbit （PCO） formations.

关键词： space vehicles - celestial mechanics - Moon - planets and satellites - formation -obliquity

Analytical model of sound transmission through laminated composite cylindrical shells considering transverse shear deformation

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Applied Mathematics and Mechanics(English Edition) 2008年第9期29卷 1165-1177页

作者： kamran daneshjou Ali Nouri Roohollah Talebitooti Department of Mechanical Engineering Iran University of Science and TechnologyNarmak

Composite structures are often used in the aerospace industry due to the advantages offered by a high strength to weight ratio. Sound transmission through an infinite laminated composite cylindrical shell is studied in the context of the transmission of airborne sound into the aircraft interior. The shell is immersed in an external fluid medium and contains internal fluid. Airflow in the external fluid medium moves with a constant velocity. An exact solution is obtained by simultaneously solving the first-order shear deformation theory （FSDT） of a laminated composite shell and the acoustic wave equations. Transmission losses （TL） obtained from numerical solutions are compared with those of other authors. The effects of structural properties and flight conditions on TL are studied for a range of values, especially, the Mach number, stack sequences, and the angle of warp. Additionally, comparisons of the transmission losses are made between the classical thin shell theory （CST） and FSDT for laminated composite and isotropic cylindrical shells.

关键词： plane wave transmission loss laminated composite shell first-order