توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱OPTIMUM DESIGN OF FUNCTIONALLY GRADED PIEZOELECTRIC CYLINDER USING COMPLEX VARIABLES METHOD
اطلاعات انتشار: کنفرانس ملی مهندسی مکانیک ایران، سال
تعداد صفحات: ۱۳
In this study, thermo–elastic behavior of cylinder made of functionally graded piezoelectric materials (FGPM) under multi–physical fields is investigated. The mechanical, thermal and electric properties, except Poisson’s ratio, are assumed to depend on variable and they are expressed as a power functions in radial direction of the cylinder using mathematical modelling. Temperature distribution is obtained using a steady–state two dimensional heat equation as a complex variables method. Stress and displacement correlations, including mechanical and thermal terms are defined based on elasticity theory. Using obtained governing equations, physical characteristics including displacement, temperature, electric potential and distribution of radial, circumferential and effective stresses are investigated graphically for a range of non–homogeneous parameters. Hence, the effect of non–homogeneity on the stresses, displacement, temperature and magnetic potential are demonstrated. Results of this investigation could be applied for optimum design of FGPM cylinder<\div>

۲VIBRATION ANALYSIS OF COUPLED PROTEIN MICROTUBULES BASED ON NONLOCAL EULER–BERNOULLI AND TIMOSHENKO BEAM THEORIES
اطلاعات انتشار: کنفرانس ملی مهندسی مکانیک ایران، سال
تعداد صفحات: ۱۲
In the present research, Euler–Bernoulli (EB) and Timoshenko beam (TB) models are developed to investigate vibrational behavior of coupled protein microtubules (MTs). MTs are hollow cylindrical filaments in the eukaryotic cytoskeleton which surrounded by filament network. Bio–medium surrounding the MTs is simulated by Winkler–Riley Model. To enhance the accuracy of results, nonlocal theory is utilized, and the motion equations as well as the boundary conditions are derived based on Hamilton’s principle.Considering surface traction of the cytosol, effects of various parameters such as environmental conditions, aspect ration of MTs and small scale on vibration characteristics of coupled MTs are obtained. Results revealed that stability of coupled MTs are strongly dependent on the ratio of length to radius so that increasing aspect ratio leads to decrease frequency of coupled MTs. The results may provide a useful reference for explaining the main role in the ultrasonic examine of microtubule organization in biomedical clinical application.<\div>

۳Prediction of elastic modulus of rectangular composite platereinforced by aligned carbon nanotubes (CNTs) by threedimensional finite element method
نویسنده(ها): ، ،
اطلاعات انتشار: کنفرانس دو سالانه بین المللی مکانیک جامدات تجربی، سال
تعداد صفحات: ۹
In this article, the elastic modulus of rectangular composite plate reinforced by aligned carbon nanotubes (CNTs) are computed by three dimensional finite element method (3D–FEM). A small slice of composite plate including the matrix and fiber is chosen for this approach. Various shapes of this slice such as square, rectangular, circular and hexagonal are considered and two cases of fiber settlement in matrix (center and corner) are examined. Compression between experimental and FEM results showed that the center cylindrical FE model has the lowest error for longitude modulus. Then, FEM results for elastic modulus of rectangular composite plate reinforced by CNTs are compared bydifferent theoretical approaches such as the extended mixture role, Halpin–Tsai and Eshelby–Mori–Tanaka approaches. This compression showed that results of Eshelby–Mori–Tanaka approach have a good agreement with the obtained FEM results for the elastic modulus of rectangular composite plate.<\div>

۴The effect of small scale on the vibrational response of nano–column based on differential quadrature method
نویسنده(ها): ، ،
اطلاعات انتشار: Journal of Transport Phenomena in Nano and Micro Scales، چهارم،شماره۲، ۲۰۱۶، سال
تعداد صفحات: ۵
The present paper deals with the dynamic behavior of nano–column subjected to follower force using the nonlocal elasticity theory. The nonlocal elasticity theory is used to analyze the mechanical behavior of nanoscale materials. The used method of solution is the Differential Quadrature Method (DQM). It is shown that the nonlocal effect plays an important role in the vibrational behavior of nano–columns. The results can provide useful guidance for the study and design of the next generation of nanodevices and could be useful in biomedical and bioengineering applications as well as in other fields related with the nanotechnology.

۵Modified Couple Stress Theory for Vibration of Embedded Bioliquid–Filled Microtubules under Walking a Motor Protein Including Surface Effects
اطلاعات انتشار: Journal of Solid Mechanics، هفتم،شماره۴، Autumn ۲۰۱۵، سال
تعداد صفحات: ۱۹
Microtubules (MTs) are fibrous and tube–like cell substructures exist in cytoplasm of cells which play a vital role in many cellular processes. Surface effects on the vibration of bioliquid MTs surrounded by cytoplasm is investigated in this study. The emphasis is placed on the effect of the motor protein motion on the MTs. The MT is modeled as an orthotropic beam and the surrounded cytoplasm is assumed as an elastic media which is simulated by Pasternak foundation. In order to consider the small scale effects, the modified couple stress theory (MCST) is taken into account. An analytical method is employed to solve the motion equations obtained by energy method and Hamilton’s principle. The influence of surface layers, bioliquid, surrounding elastic medium, motor proteins motion, and small scale parameter are shown graphically. Results demonstrate that the speed of motor proteins is an effective parameter on the vibration characteristics of MTs. It is interesting that increasing the motor proteins speed does not change the maximum and minimum values of MTs dynamic deflection. The presented results might be useful in biomedical and biomechanical principles and applications.

۶Nonlocal Vibration of Y–SWCNT Conveying Fluid Considering a General Nonlocal Elastic Medium
اطلاعات انتشار: Journal of Solid Mechanics، هشتم،شماره۲، Spring ۲۰۱۶، سال
تعداد صفحات: ۱۵
In this paper, a nonlocal foundation model is proposed to analyze the vibration and instability of a Y–shaped single–walled carbon nanotube (Y–SWCNT) conveying fluid. In order to achieve more accurate results, fourth order beam theory is utilized to obtain strain–displacement relations. For the first time, a nonlocal model is presented based on nonlocal elasticity and the effects of nonlocal forces from adjacent and non–adjacent elements on deflection are considered. The Eringen’s theory is utilized due to its capability to consider the size effect. Based on Hamilton’s principle, motion equations as well as boundary conditions are derived and solved by means of hybrid analytical–numerical method. It is believed that the presented general foundation model offers an exact and effective new approach to investigate vibration characteristics of this kind of structures embedded in an elastic medium. The results of this investigation may provide a useful reference in controlling systems in nano–scale.

۷Smart Vibration Control of Magnetostrictive Nano–Plate Using Nonlocal Continuum Theory
اطلاعات انتشار: Journal of Solid Mechanics، هشتم،شماره۲، Spring ۲۰۱۶، سال
تعداد صفحات: ۱۵
In this research, a control feedback system is used to study the free vibration response of rectangular plate made of magnetostrictive material (MsM) for the first time. A new trigonometric higher order shear deformation plate theory are utilized and the results of them are compared with two theories in order to clarify their accuracy and errors. Pasternak foundation is selected to modelling of elastic medium due to considering both normal and shears modulus. Also in–plane forces are uniformly applied on magnetostrictive nano–plate (MsNP) in x and y directions. Nonlocal motion equations are derived using Hamilton’s principle and solved by differential quadrature method (DQM) considering different boundary conditions. Results indicate the effect of various parameters such as aspect ratio, thickness ratio, elastic medium, compression and tension loads and small scale effect on vibration behaviour of MsNP especially the controller effect of velocity feedback gain to minimizing the frequency. These finding can be used to active noise and vibration cancellation systems in micro and nano smart structures.
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