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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

Power transmission through double-walled laminated composite panels considering porous layer-air gap insulation

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Applied Mathematics and Mechanics(English Edition) 2014年第11期35卷 1447-1466页

作者： M.H.SHOJAEIFArD r.talebitooti B.rANJBAr r.AHMADI School of Mechanical Engineering Iran University of Science & Technology School of Automotive Engineering Iran University of Science & Technology

The acoustic behavior of double-walled laminated composite panels consisting of two porous and air gap middle layers is studied within the classical laminated plate theory （CLPT）. Thus, viscous and inertia coupling in a dynamic equation, as well as stress transfer, thermal and elastic coupling of porous material ave based on the Biot theory. In addition, the wave equations are extracted according to the vibration equation of composite layers. The transmission loss （TL） of the structure is then calculated by solving these equations simultaneously. Statistical energy analysis （SEA） is developed to divide the structure into specific subsystems, and power transmission is extracted with balancing power flow equations of the subsystems. Comparison between the present work and the results reported elsewhere shows excellent agreement. The results also indicate that, although favorable enhancement is seen in noise control particularly at high frequencies, the corresponding parameters associated with fluid phase and solid phase of the porous layer are important on TL according to the boundary condition interfaces. Finally, the influence of composite material and stacking sequence on power transmission is discussed.

关键词： laminated composite plate double panel sound transmission loss porousmaterial statistical energy analysis (SEA)

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

BENDING BEHAVIOr OF EMPTY AND FOAM-FILLED ALUMINUM TUBES WITH DIFFErENT CrOSS-SECTIONS

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Acta Mechanica Solida Sinica 2012年第6期25卷 616-626页

作者： M. H. Shojaeifard H. r. Zarei r. talebitooti M. Mehdikhanlo School of Automotive Engineering Iran University of Science and Technology Faculty of Aerospace Engineering Aeronautical University of Science and Technology

In this paper, the energy absorption mechanism of empty and foam-filled aluminum tubes with different cross-sections （circular, square and elliptic） under bending load is investigated numerically. The load-displacement curves of the present simulations are in very good agreement with those of published experimental data. Here, the existing analytical formulations are reviewed and compared with experimental results. In addition, the effects of different cross-sections and wall thicknesses on the energy absorption capacity and specific energy absorption of these tubes are fully investigated. The results indicate that the energy absorption of an elliptic foam-filled tube with 1.5 mm and 2 mm thicknesses increases about 45% and 73% in comparison with a square one, respectively.

关键词： plastic bending foam filled energy absorption