@article{ author = {Yousefpour, amin and Safikhani, Mohammad and HairiYazdi, Mohammad Reza and bahrami, arash}, title = {Piezomagnetoelastic vibration energy harvesting with superharmonic resonance}, abstract ={Nonlinearities give rise to secondary resonances such as superharmonic and subharmonic resonances. The superharmonic resonance can activate large-amplitude responses when the excitation frequency is a fraction of the fundamental frequency of the system. These low frequency excitations are very beneficial for energy harvesting systems. This paper presents an analytical investigation of vibrational energy harvesters with superharmonic excitation in a pietzomagnetoelastic configuration. A piezomagnetoelastic power generator is assumed to operate in the monostable and bistable modes. Nonlinear differential equations governing the oscillations of the system is solved using the method of multiple scales. System responses to the superharmonic resonance including the cantilever tip displacement and the output voltage are determined. It is found that employing the superharmonic resonance can increase the amount of harvested energy in the system. The root mean square value of the output voltage is obtained for several cases in both monostable and bistable modes. The power generated in monostable and bistable modes is then compared through numerical simulations. It is observed that the bistable mode is more convenient for harvesting energy. In addition, a Rung-Kutta numerical scheme is used to solve the differential equations. It is shown that the perturbation solution is in a close agreement with the numerical solution.}, Keywords = {Energy harvesting,piezomagnetoelastic,superharmonic resonance,method of multiple scales,}, volume = {18}, Number = {7}, pages = {1-4}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-14113-en.html}, eprint = {http://mme.modares.ac.ir/article-15-14113-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} } @article{ author = {moradi, hosein and Shafaee, Maziar and Sabour, Mohammad Hossei}, title = {Evaporation behavior of R-600a considering exergy losses in horizontal smooth and enhanced tubes}, abstract ={In the present study, evaporation heat transfer and frictional pressure drops of refrigerant R-600a (iso-butane) inside a helically dimpled tube and a plain tube of internal diameter 8.3mm were measured and analyzed. All tests were performed at different vapor qualities up to 0.8 and average saturation temperatures ranging between 38 and 42℃. Refrigerant mass fluxes varied in the range of 114-368 kg/m2s. The inner surface of the helically dimpled tube has been designed and reshaped through three-dimensional material surface modifications consists of both shallow and deep protrusions which is placed evenly in helical directions on the tube wall. The experimental results show that the heat transfer coefficients of the dimpled tube are 1.29-2 times larger than a smooth tube with a pressure drop penalty just ranging between 7% and 103% larger than the smooth tube. Moreover, Performance Evaluation Criteria (PEC) dubbed Penalty Factor (PF) and Total Temperature Penalization (TTP) boiling inside a helically dimpled tube and a smooth tube were analyzed which are a convenient way to relate the two penalization components and provides a rational method to compare the exergy losses associated with frictional pressure drop and heat transfer coefficient.}, Keywords = {R-600a,evaporation,Performance Criterion,Exergy,}, volume = {18}, Number = {7}, pages = {5-9}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-15849-en.html}, eprint = {http://mme.modares.ac.ir/article-15-15849-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} } @article{ author = {Fouladi, Nematollah}, title = {Numerical investigation of flow transient phase of motor burnout in an altitude test simulator}, abstract ={In this research, the performance study of an altitude test simulator at transient phase of motor burnout is conducted by numerical approach. Using a time dependent pressure profile of a motor in burnout phase, the unsteady exhaust flow is simulated in the main sections of the altitude test simulator, i.e. high expansion ratio nozzle, second throat exhaust diffuser, and vacuum chamber. Present investigation shows that in spite of the high pressure starting condition of the altitude simulator, the supersonic flow in the diffuser tends to breakdown at relatively low combustion pressure in the motor terminating phase. At the breakdown condition, the nozzle exhaust hot gases directed into the vacuum chamber through the annular gap between nozzle and diffuser walls. Present simulation shows that the overall temperature of fluid in vacuum chamber is reached up to 2000 K after the motor burnout. Really, It is potentially dangerous for measurement instruments inside the vacuum chamber. Furthermore; in this research, the influences of backflow arrester (BFA) in variations of vacuum chamber temperature are studied at this transient terminating phase. It has been shown that, the BFA can decrease the exhaust streaming into the chamber in initial breakdown periods. Results show that utilizing a suitable BFA size, the safe temperature condition could be established in vacuum chamber during and after the transient terminating phase of motor.}, Keywords = {Altitude test simulator,supersonic diffuser,motor burnout,numerical simulation,backflow arrester,}, volume = {18}, Number = {7}, pages = {10-19}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-14973-en.html}, eprint = {http://mme.modares.ac.ir/article-15-14973-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} } @article{ author = {Fasihi, Farhad and Noori, Sahar and EidiAttarzadeh, Masou}, title = {Investigation of radiative heat transfer effect on the SM1 flame structure with steady flamelet method}, abstract ={Abstract Thermal radiation plays a key role in the heat transfer between the flame and its surroundings. It is essential to provide a reliable method for measurement of flame radiation in the combustion study. Also, it is challenging to measure the radiation flux from the flame in the chamber due to the effect of the walls. The radiation emitted from the walls and the reflection of the flame radiation from the walls interferes with the measurement of the flame radiation. High temperature or high reflection walls can increase the error in the measurement of flame radiation. In this paper, various parameters affecting the flame radiation have been investigated. These studies are based on the wall incident radiation and the wall radiation heat flux. To calculate the flame radiation, a theoretical method is presented which is compared with the CFD simulation results to confirm its correctness. To simulate the flame SM1 of the University of Sydney, a steady flamelet combustion model has been used with the k-ε modified turbulence model. Due to the low optical thickness of the model, the DO radiation model is used to simulate CFD. The CFD results are in good agreement with theoretical results, and the estimation of flame emission are accurately acceptable. The results show that the flame radiation differs from the wall radiation by more than 25%, when the wall radiation coefficient will be smaller than 0.8 or the wall temperature will be more than 330k.}, Keywords = {Flame radiation,Radiative heat flux,Wall incident radiation,SM1 Burner,DO radiation model,}, volume = {18}, Number = {7}, pages = {20-29}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-13841-en.html}, eprint = {http://mme.modares.ac.ir/article-15-13841-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} } @article{ author = {}, title = {Thermodynamic transient modeling of tank pressurization by combustion}, abstract ={Main tank injection (MTI) is a pressurization method which employs through combustion inside a reservoir. MTI is simpler and lighter as compared with the common pressurization methods, hence make in suitable for mission launching applications. In this study we evaluated the MTI pressurization system based on unsteady-thermodynamics approach. We used a numerical code which can be performed for the vessels with diameter in the range of 13inch to 60 inch. The proper model for regent injection into the tank in order to provide the demand pressure of the tank is acquired through transient thermodynamics equations. Composition and properties of the pressurizing gas and rate of ullage saturation with propellant vapors are reported based on extensive mass spectrometer gas analysis, an investigation of propellant-degradation due to the reaction process and dilution by condensate is also-Included. The algorithm also obtains the ullage gas temperature and the wall temperature of the tank by using the heat transfer between the ullage gas, the liquid inside the tank, and tank wall. Finally the numerical results are compared with the experimental data, while shows a good agreement between.}, Keywords = {Pressurization,Main tank injection,Thermodynamic,Transient,}, volume = {18}, Number = {7}, pages = {30-40}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-16200-en.html}, eprint = {http://mme.modares.ac.ir/article-15-16200-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} } @article{ author = {Bozorgi, Mehran and Karami, Maryam and Delfani, Shahram}, title = {Energy and exergy analysis of direct absorption solar collector by using silver nanofluid}, abstract ={In this study, energy and exergy efficiency of residential-type direct absorption solar collector using PVP-coated silver nanofluid has been evaluated experimentally. First, stability and thermophysical and optical properties of nanofluid have been considered using the theoretical and experimental methods. Then, outdoor thermal performance of collector is investigated using the experimental setup based on EN12975-2. Results of energy analysis show that the collector efficiency is increased by increase of flowrate and concentration of nanofluid asymptotically. It is observed that exergy efficiency is firstly increased by nanofluid concentration and then, decreased after reaching the optimum value. The optimum concentration was 500 ppm for all flowrates. The variation of exergy efficiency by reduced temperature difference is similar to volume fraction. The optimum exergy efficiency is obtained at 0.01 m2K/W. The decrease of exergy efficiency by flowrate indicated that exergy losses due to pressure drop have the significant effect on the collector performance.}, Keywords = {Direct Absorption Solar collector,Silver Nanofluid,Extinction Coefficient,Exergy Efficiency,}, volume = {18}, Number = {7}, pages = {41-49}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-15710-en.html}, eprint = {http://mme.modares.ac.ir/article-15-15710-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} } @article{ author = {Hamisi, Mohammad and MoussaviTorshizi, Seyed Ebrahim}, title = {Experimental study of aging effect on mechanical and vibrational properties on carbon steel SA516}, abstract ={In long-terms of overheating conditions, structural changes are the most important cause of mechanical deterioration and reduce the life of hot components. Given the difficulty or costliness of tests needed to assess the remaining life, searching for a non-destructive, simpler and more accurate way to estimate the remaining life of hot components and assess their remaining life is essential and have many economic benefits. The purpose of this study is to investigate the effect of structural changes on natural frequencies and damping coefficients of samples of carbon steel SA516-Grade55 so that, if there are significant effects, this method will be developed for other metals, in particular hot power plant parts. In this research, severe structural changes were observed on the samples by performing heat treatment of aging. As perlite decompose into ferrite and spheroidal carbides in the boundaries. With increasing structural changes, it was found that the natural frequencies of the first to sixth modes and the elastic modulus are decreased and the coefficients of damping and logarithmic decrease are increased significantly. These promising results are the elaboration of a non-destructive new method for estimating the remaining life for components of different types under long-term overheated operation conditions.}, Keywords = {Life estimation,Carbon steel,Aging,Microstructural change,Mechanical and Vibrational properties,}, volume = {18}, Number = {7}, pages = {50-55}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-15947-en.html}, eprint = {http://mme.modares.ac.ir/article-15-15947-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} } @article{ author = {Maleki, Sattar and Andakhshideh, Atieh and Malaeen, Mehdi}, title = {A Novel procedure for experimental determination of Mode I strain energy release rate in unlike double cantilever beam}, abstract ={Dual laminate pipes made of thermoset polymer composite structure and thermoplastic liner are the only alternative in pipelines conveying high temperature corrosive fluids. Investigating the bonding between thermoset composite and thermoplastic liner is very important in these pipelines. Calculating the strain energy release rate of first mode of failure is very important criteria in bonding strength and failure of doulas pips. ASTM-D5528 is the standard for experimental test procedure of strain energy release rate of symmetric double cantilever beam. In this study, using the classical laminates theory, the general equation for determination the laminates thicknesses in unlike double cantilever beam is presented, for the first time. To study the validity of the equation, in unlike double cantilever beam samples consists of laminates with different thicknesses are manufactured for the experimental tests. Upper, lower and bonding regions consist of composite made of unidirectional fiberglass/Vinylester resin, PVCU and epoxy or Vinylester primers, respectively. The samples of this study are manufactured base on the practical case studies of chemical fluid pipelines with chlor-alkali process like Arvand Petrochemical units. The main aim of this work is to help manufacturers of these unites equipment to have practical guideline. To qualify the efficiency of the proposed equation, finite element simulation base on the virtual crack closure technique is presented. Good agreement is achieved in comparing the numerical and experimental results that shows the efficiency and accuracy of the proposed equation.}, Keywords = {Strain energy release rate,First mode of failureI,Unlike double cantilever beam,Thermoplastic liner,}, volume = {18}, Number = {7}, pages = {56-67}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-14828-en.html}, eprint = {http://mme.modares.ac.ir/article-15-14828-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} } @article{ author = {Khorrambakht, Ehsan and Roshanian, Jafar and Khodabakhsh, Amir Hossei}, title = {Performance Study of Distributed Control Algorithm for Cooperative Search using Multi-Agent System}, abstract ={Vastness of operation airspace and uncertain environment in aerial search missions, makes utilizing multiple intelligent agents more preferable to integrated centralized systems due to robustness, parallel computing structure, scalability, and cost optimality of distributed systems. Cooperative search missions require the search space to be divided properly between agents. In order to minimize the uncertainty, the agents will calculate the best path in the assigned space partition. According to the communication topology, environmental information and the near-future decisions are shared between agents. In this paper, cooperative search using multiple UAVs has been considered. First, mathematical representation of the search space, kinematic and sensor model of UAVs, and communication topology have been presented. Then, an approach has been proposed to update and share information using the Bayes’ rule. Afterwards, path planning problem has been solved using different optimization algorithms namely First-order Gradient, Conjugate Gradient, Sequential Quadratic Programming, and Interior Point Algorithm. Finally, the performance of these algorithms have been compared according to mean uncertainty reduction and target detection time.}, Keywords = {Multi-Agent System,Cooperative Search,Distributed Control,Optimization Algorithms,Bayes Rule,}, volume = {18}, Number = {7}, pages = {68-78}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-14870-en.html}, eprint = {http://mme.modares.ac.ir/article-15-14870-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} } @article{ author = {Fasaeiyan1, Niloofar and Soltani, Madjid and Ta’atizadeh, Erf}, title = {Image-based computational modeling of the FDG tracer in a solid tumor with a consideration of capillaries network}, abstract ={In a computational modeling of drug delivery and PET tracers to cancer tissues, the most difficult part is a consideration of a complexity of capillaries network. Because of the key role of blood flow in tumor feeding and growth that also carrying radiotracer into both normal and cancerous tissues, there are various studies have been done on the formation of new blood vessels and blood flow around a tumor. In this work, we used an image of a complex capillaries network to simulate FGD tracer distribution within both normal and cancerous tissues. Firstly, one RGB image was imported as an input image which consisted of the capillaries network and has been processed and made ready for creating 2D geometry from it. The creation of 2D geometry from the input image is consisted two areas: Pre-processing and Post-Processing the input image for preparation of it for the creation geometry by capturing the capillaries from a background of whole of the picture. In the next stage, with a usage of the achieved geometry and by coupling blood flow and interstitial flow, pressure and velocity distribution in the capillaries and both tumor and normal tissues were accomplished. Finally, by applying CDR (Convection-Diffusion-Reaction) equations for FDG tracer, distribution of it was acquired within the whole normal and cancerous domain. Observing FDG tracer CDR modeling helped us find tracer distribution with both time and space.}, Keywords = {PET tracer,FDG tracer,Solid tumor,Capillaries network,Image processing,Convection-Diffusion-Reaction equations.,}, volume = {18}, Number = {7}, pages = {88-96}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-16233-en.html}, eprint = {http://mme.modares.ac.ir/article-15-16233-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} } @article{ author = {Gholipoor, Ahad and Mohammadpourfard, Mous}, title = {Study of the effect of tools ultrasonic vibrations and external magnetic field on machined surface integrity at EDM process}, abstract ={Despite the unique usage of electrical discharge machining process at machining in small dimensions, machining complex shapes and machining of high-strength parts such as ceramics and heat treated steels, which can’t be machined by traditional machining methods, low machined surface integrity achieved by electrical discharge machining process is one of the most important limitations of this process. In this investigation the machined surface integrity will be improved by applying ultrasonic vibrations to tool electrode and external magnetic field around gap distance of electrical discharge machining process, simultaneously. So several experiments were designed and performed based on full factorial method by selecting pulse current and pulse duration as the most important input parameters, in order to study the effects of pulse current and duration on surface integrity of workpiec machined by this hybrid process and to investigate the effects of tools ultrasonic vibrations and external magnetic field on machined surface roughness and integrity of machined surface. According the results, machined surfaces roughness is increased by applying ultrasonic vibrations to tool electrode and external magnetic field around gap distance of electrical discharge machining process, simultaneously, while the SEM pictures of machined surfaces showed that the, amount of created surface cracks, blowholes, globules and beads of debris are decreased and integrity of machined surfaces by EDM process is improved by applying ultrasonic vibrations to tool electrode and external magnetic field around gap distance, simultaneously.}, Keywords = {Electrical Discharge Machining,External Magnetic Field,Tools Ultrasonic Vibrations,Machined Surface Integrity,}, volume = {18}, Number = {7}, pages = {97-107}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-16818-en.html}, eprint = {http://mme.modares.ac.ir/article-15-16818-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} } @article{ author = {nazari, ali and naderi, ali asghar}, title = {Free vibration analysis of designed FML circular cylindrical shell based on optimum fiber orientation}, abstract ={The big deformation of composite structures under dynamic loads is one of the most disadvantages of these structures that cause to loss of stiffness of them. The using of fiber metal laminated shell that named FML in abbreviation is one of the ways to decrease the adverse effect of dynamic load. In this study the optimum fiber orientation of composite layers of the FML circular cylindrical shells are determined to more decrease the adverse effect of dynamic loads. For this purpose the fiber orientation of composite layers of the FML circular cylindrical shells are changed frequently and each cases being subjected to axial compressive load and with use of ABAQUS program the tension of all composite layers are calculated for all cases. Then with use of MATLAB program the fiber orientation that cause to maximum stiffness based on maximum tension fracture criterion is selected. The free vibration analysis is used for determination the accuracy and performance of design process. The results of free vibration analyses show that determination of the optimum fiber orientation cause to improvement of the FML shell natural frequency. Energy method and high order shear deformation theory is used to define the equation of motion. Full Calculus method is used for optimization in order to apply the exact result.}, Keywords = {Free vibration,fiber metal laminated shell,fracture criterion,fiber orientation,}, volume = {18}, Number = {7}, pages = {108-118}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-16084-en.html}, eprint = {http://mme.modares.ac.ir/article-15-16084-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} } @article{ author = {aghazadeh, naghi and Khalilarya, Shahram and Jafarmadar, samad and ChitsazKhoyi, At}, title = {Thermoeconomic analysis of a novel trigeneration system based on solid oxide fuel cell and gas turbine with hydrogen fuel}, abstract ={In this article, a new power, cooling and heating cogeneration system consisting of a solid oxide fuel cell (SOFC) - gas turbine (GT), a heat recovery steam generator (HRSG), Generator-Absorber-heat eXchange (GAX) absorption refrigeration cycle and a heat exchanger for heat recovery (HR) has been studied from a thermodynamic and economic perspective. The modeling of this cycle was done by solving the electrochemical, thermodynamic and exergoeconomic equations for fuel cell and system components, simultaneously. The results showed that the exergy of our proposed combined cycle is 14.9% more and the irreversibility rate of this cycle is 10.6% less than that of the combined SOFC-GT-GAX systems in the same conditions. Also, the fuel cell and the afterburner have the highest rate of exergy destruction among other components due to irreversibility. Exergoeconomic analysis showed that the sum of uint cost of products (SUCP), the exergoeconomic factor, the capital cost rate and the exergy destruction cost rate for the overall system is equal to 331.1 $/GJ, 29.3%, 10.47 $/h and 25.32 $/h, respectively. Parametric studies showed that increasing the current density will increase the net electrical power, heating capacity of HRSG and HR heat exchanger, cooling capacity and total irreversibility. Also, with increasing of the current density, both the exergy efficiency and SUCP decrease.}, Keywords = {Solid oxide fuel cell,GAX,HRSG,Cogeneration,Thermodynamic and Exergoeconomics,}, volume = {18}, Number = {7}, pages = {119-130}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-14159-en.html}, eprint = {http://mme.modares.ac.ir/article-15-14159-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} } @article{ author = {nazemosadatarsanjani, sayed mahmoud and badrossamay, mohsen and Foroozmehr, Ehs}, title = {Preparation of Alumina Particles Coated with a Thin Layer of Amorphous Thermoplastic via Phase Inversion Process for Indirect SLS Applications}, abstract ={Additive manufacturing or 3D printing processes through which applicable complicated parts are directly made based on 3D model of the part has been extensively addressed in numerous research and development tasks for the past years. Certain merits such as decline of time, cost of design and manufacturing of product, processing different engineering materials, manufacturing parts with highly complicated geometries, and manufacturing customized parts should be noted in the case of adopting these methods. Indirect selective laser sintering is one of the interesting methods of integrated manufacturing which could be used for manufacturing of complicated pieces and certain materials such as ceramics with a high melting point and difficult manufacturing process through typical methods. In the present study, indirect SLS of spherical alumina powder particles with a thin layer of amorphous thermoplastic (PMMA and PS). In order to coat alumina particles with different weight percent of thermoplastic, the new method of phase Inversion process was used. Due to significance of geometry and dimensions of the final part, the least probable thickness of thermoplastic was used for manufacturing of parts based on SLS method. In the present study, evaluation of coating and method of coating have been discussed. The evaluative techniques include assessment through scanning electron microscopy, analytical results of Fourier transform infrared spectroscopy and thermogravimetric analysis and differential scanning calorimetry. Finally, green parts where produced based SLS method and through optimal values of laser parameters and selection of alumina powder particles with thinnest thermoplastic coating.}, Keywords = {Coating,Alumina,Laser Sintering,Polystyrene,Polymethyl methacrylate.,}, volume = {18}, Number = {7}, pages = {131-141}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-16825-en.html}, eprint = {http://mme.modares.ac.ir/article-15-16825-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} } @article{ author = {safikhanimahmoudi, mohammad and yousefpour, amin and bahrami, arash}, title = {Higher-mode Excitation in The Non-contact Atomic force Microscopy}, abstract ={In the present research, higher resonance frequencies are employed to improve the performance of the atomic force microscopy in the non-contact mode. Conventional models already used in the literature to study AFM microcantilever dynamics such as point-mass approach are not only incapable of modeling higher vibrational modes but also fail to predict microcantilever complicated dynamics with a sufficient accuracy. In this paper, the Hamilton’s extended principle is used to obtain equations governing the nonlinear oscillations of the AFM probe. Euler-Bernoulli beam assumptions and small deflection theory are assumed. The resulting partial differential equation is often converted to a set of ordinary differential equations and then this set is solved either numerically or based on perturbation methods. In the present research, however, the partial differential equation is attacked directly by a special perturbation technique. The accuracy of the present method is then verified by a combination of the Galerkin discretization scheme and a Rung - Kutta numerical solution. Finally, different behaviors of the AFM probe including static behavior, linear mode shapes and frequency response curves are investigated through several numerical simulations. It is found out that higher vibrational modes have smaller frequency shift. It is also found out that higher modes are faster in gathering surface information and also more sensitive to the excitation.}, Keywords = {AFM,higher -mode excitation,non-contact mode,perturbation theory,Galerkin discretization,}, volume = {18}, Number = {7}, pages = {149-158}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-16187-en.html}, eprint = {http://mme.modares.ac.ir/article-15-16187-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} } @article{ author = {Gholami, Y. and Ansari, Rez}, title = {Three dimensional analysis of temperature-dependent nonlinear mechanical behaviors of functionally graded rectangular plates resting on Winkler–Pasternak elastic foundation}, abstract ={The temperature-dependent nonlinear mechanical behaviors of functionally graded rectangular plates in the thickness direction resting on Winkler–Pasternak elastic foundation are investigated using the three-dimensional theory of elasticity. The material properties are temperature-dependent and varied in the thickness direction based on a power-law. Considering the nonlinear Green-Lagrange strain relation, the geometric nonlinearity is taken into account. After obtaining the potential strain, kinetic energies, taking into account the effects of the temperature and the elastic foundation, the Hamilton’s principle is used to derive the nonlinear three-dimensional governing equations and corresponding boundary conditions. To solve the nonlinear free vibration problem, first, the generalized differential quadrature (GDQ) method is used to discretize the nonlinear coupled governing equations in the space domain. Then, the obtained equations are converted to the time-dependent ordinary differential equations using the numerical-based Galerkin scheme and the time periodic discretization (TPD) are used to discretize them in the time domain. Finally, the arc-length method is employed to find the frequency-response of system. Also, to solve the nonlinear bending problem, by neglecting the effect of inertia and using the arc length algorithm, the maximum deflection versus the applied load is obtained. The effects of different parameters such as length-to-thickness ratio, Winkler–Pasternak elastic foundation coefficients, uniform and linear temperature rises and volume fraction index on the frequency response and maximum deflection of functionally graded plates with various edge conditions are studied.}, Keywords = {Functionally graded plate,Nonlinear mechanical behaviors,3D theory of elasticity,Numerical solution procedure,}, volume = {18}, Number = {7}, pages = {159-169}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-15725-en.html}, eprint = {http://mme.modares.ac.ir/article-15-15725-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} } @article{ author = {ShahbaziGandomkari, Rahmat and DarvishGohari, Hame}, title = {Passive control of acoustic wave transmitted through a doubly curved shell by piezoelectric material}, abstract ={In this work, transmitted sound power control through a doubly curved laminated shell by the aid of RL-shunt is investigated. Therefore, vibration equations of a doubly curved shell with piezoelectric layers are firstly derived utilizing Hamilton’s principle. Then, the obtained equations are verified considering the results reported by other researchers. In addition, by applying a shunt circuit, which is parallel to the piezoelectric layer, the effect of resonant shunt method in passive control of the sound transmission loss of the shell is explored. It is indicated that with applying the shunt circuit, and then tuning the circuit with the resonance frequency, the amplitude of sound transmission loss has been significantly reduced. In next step, by applying three shunt circuits, parallel with one piezoelectric layer, it is found that passive control of this doubly curved structure can decrease the sound transmitted in resonant frequency. Finally, performance of these circuits is improved by using genetic algorithm to optimize RL-shunt circuit parameters. As a prominent result, it is shown that this method has an excellent effect on improvement of sound transmission loss up to 80dB.}, Keywords = {Passive control,doubly curved shell,shunt circuit,genetic algorithm,}, volume = {18}, Number = {7}, pages = {170-176}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-16465-en.html}, eprint = {http://mme.modares.ac.ir/article-15-16465-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} } @article{ author = {Ghanati, Golsa and Azadi, Shahram}, title = {Active control of vehicle’s interior sound field with considering acoustic structural coupling}, abstract ={The sound level inside the automobile cabin plays a major role on passengers’ comfort. The sound field inside the vehicle cabin depends on acoustical and structural characteristics and also interaction of acoustical and structural domains. In this paper, a coupled acoustic structural modal and harmonic analysis of simple automobile is performed with the methods of direct coupling (with finite element tool) and modal coupling. So with comparison of results from these two methods, the accuracy of modal coupling method is investigated. Also the optimal MIMO controller is designed to reduce sound level at occupants’ ear positions. The results of coupled and uncoupled modal analysis show that the contribution of uncoupled acoustical and structural modes on coupled response could be estimated and used to understand booming phenomena. Also the presented state space model, which is constructed based on uncoupled modes, shows a good accuracy and reduces computational costs significantly. The results of time and frequency response of sound pressure level at occupants’ ear positions show that the designed controller is attained to attenuate sound field at desired frequency range and the area of quiet zone inside the cabin consists of all occupants’ hearing positions and therefore controller acts globally successful in desired frequency range.}, Keywords = {Acoustic structural coupling,Modal coupling,Finite Element Method,Active Sound Control,MIMO optimal control,}, volume = {18}, Number = {7}, pages = {177-186}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-16066-en.html}, eprint = {http://mme.modares.ac.ir/article-15-16066-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} } @article{ author = {Aaraj Khodaii, Seied Javad and Barazandeh, Farshad and Adibi, Hamed and Sarhan, Ahme}, title = {Optimization of Grinding partially stabilized zirconia (PSZ) for dental Implant application}, abstract ={Titanium is currently widely used as dental implant, but it may cause allergic problems. For this reason, the use of partially stabilized zirconia (PSZ) in dental applications has increased in recent years. Because of extreme hardness and brittleness of ceramic (PSZ) and in order to achieve dimensional and geometrical accuracy, grinding is necessary. In this research, a comprehensive study was carried out to investigate the effect of the grinding parameters of PSZ on surface roughness, grinding cost and PSZ phase transformation. It was observed that, increasing both depth of cut and feed rate results in an increase on tetragonal to monoclinic phase transformation. It was also observed that using a metal bond grinding wheel with higher concentration and larger abrasive size results in lower grinding cost. It was observed that using resin bond grinding wheels instead of metal bond grinding wheels, results in average 8% lower surface roughness. However, an increase in grinding wheel concentration results in a decrease in the surface roughness. Response surface method (RSM) was used to find an optimum condition and create a mathematical model between inputs and outputs and it was shown that the average R-square of the model was more than 0.90. PSZ microstructure and surface roughness could be controlled by controlling the grinding parameters. Using a metal bond grinding wheel with higher concentration and larger abrasive size results in lower grinding cost.}, Keywords = {Implant,Zirconia,Grinding,Surface roughness,grinding cost,}, volume = {18}, Number = {7}, pages = {187-194}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-16796-en.html}, eprint = {http://mme.modares.ac.ir/article-15-16796-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} } @article{ author = {ahmadkhah, anvar and Arvin, Iman and davoudinik, Alirez}, title = {Effect of dynamic behavior of fins in natural convection in a square cavity}, abstract ={The effect of the dynamic behavior of fins on the natural convection heat transfer inside a square cavity was studied numerically. Attachment of conductive thin and flexible fins with length equal to 0.2, positioned at 9 locations on both hot and cold wall was examined. The top and the bottom horizontal walls of the cavity were insulated while their left and the right vertical walls were maintained at a constant temperature T_h and T_c. The numerical scheme is based on the finite element method adapted to triangular non-uniform mesh element by a non-linear parametric solution algorithm. Furthermore, the dimensionless equations of flexible parts of the cavity were solved using the Newton-Raphson method. Based on our results, the dynamic behavior of the fins leads to decrease the rate of heat transfer in compared to the rigid fin. It also found the shape of the fins and its positions play an important role in decrease or increase of heat rate inside the cavity.}, Keywords = {Natural convection,elastic fin,dynamic mesh,Lagrangian-Eulerian.,}, volume = {18}, Number = {7}, pages = {195-204}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-16793-en.html}, eprint = {http://mme.modares.ac.ir/article-15-16793-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} } @article{ author = {shojaeefard, mohammad hassan and hosseini, seyed ehsan and zare, jav}, title = {Numerical simulation and multi-objective optimization of the centrifugal pump inducer}, abstract ={Inducers are important devices which are mounted upstream of the inlet to the main impeller of the centrifugal pump to achieve higher suction performance and rotate with the same speed as the impeller. Inducers improve the hydraulic performance and lifespan of the pump through increasing the inlet pressure, but the quantity of the improvement is dependent on the geometrical parameters of the inducer. Therefore, the optimization of these parameters is crucial. In the present study, the performance of an inducer is optimized by considering the inlet tip blade angle, the outlet tip blade angle and the ratio of the outlet hub radius to inlet hub radius as design variables and the head coefficient, the hydraulic efficiency and the required net positive suction head as objective functions. The inducer performance is simulated using 3-D computational fluid dynamics and compared with experimental data which shows the validity of the used method and assumptions. The artificial neural network is used to relate between design variables and objective functions. Then, the Pareto fronts are plotted using the modified non-dominated sorting genetic algorithm II and the proposed optimum points are presented using nearest point to the ideal point method. Using multi objective optimization, the head coefficient, the hydraulic efficiency and the net positive suction head are improved 14.3%, 0.3% and 30.2%, respectively. Recommended design points unveil important optimal design principles that would not have been obtained without the use of a multi objective optimization approach.}, Keywords = {Inducer,Centrifugal pump,Artificial neural network,Multi-objective optimization,}, volume = {18}, Number = {7}, pages = {205-216}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-15078-en.html}, eprint = {http://mme.modares.ac.ir/article-15-15078-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} } @article{ author = {Mousavion, Mohammad and Mashayekhi, Mohammad and Jamshidian, Mostafa and Badnava, Hojjat}, title = {Implementation of the phase-field method for brittle fracture and application to porous structures}, abstract ={Recently, the phase field approach has gained popularity as a versatile tool for simulating crack propagation. The purpose of this study is to employ the capabilities of the phase field method for crack growth modeling in complex structures such as porous media. The phase field method does not need predefined cracks and it can simulate curvilinear crack path. This goal is accomplished by replacing the sharp discontinuities with a scalar damage phase field parameter representing the diffuse crack topology. To simulate brittle fracture in this study, the equations of elastic displacement field and fracture phase field are first introduced. Afterwards, using the weak form of the equations, the staggered solution of the equations is performed. To implement the equations in the finite element method, the Abaqus software with User Element Subroutine (UEL) is used. Given that the bone structure is somehow a porous structure, a representative volume element of the bone is selected for phase field simulation. In order to verify the developed model, the tensile test of the single edge notched specimen has been simulated. Subsequently, crack propagation in a porous media with different porosities under tensile loading was simulated. The simulation results illustrate the capability of the phase field method in predicting crack growth in geometrically complex structures. In addition, the load-carrying capacity or the strength of the porous structure continuously decreases with increasing porosity and noteworthy is that such a strength is suddenly decreased around a critical porosity value.}, Keywords = {Phase field method,Brittle fracture,Porous structures,Finite element method.,}, volume = {18}, Number = {7}, pages = {217-225}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-14371-en.html}, eprint = {http://mme.modares.ac.ir/article-15-14371-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} } @article{ author = {Sabokrouh, Majid and Farahani, Mohammadrez}, title = {Mathematical modeling of residual stress distribution in girth welding of high strength low alloy steel gas pipelines}, abstract ={In this paper, the numerical distribution of residual stresses in the girth weld were determined in two (hoop an axial) direction. Two API X70 steel pipes of 56 inch outside diameter were girth welded first. Hole drilling strain gage test were conducted for strain measurement on the external surface of the pipes. The values of residual stresses were determined then from strain data using ASTM 837 standard. The values of residual stresses were determined. Next, distribution of residual stresses were assessed using spline and approximating polynomials. The well-behaved spline and polynomials, confirm the accuracy of residual stress results from experiment. The result showed lower-order polynomials have more suitable behavior in residual stress distribution. Noting to impossibility of using semi-destructive hole drilling strain gage test in project’s real situations, we can make use of these curves in assessing and estimating residual stresses distribution of similar welding. The most stable polynomial estimation curves for evaluating hoop and axial residual stress distribution are respectively third and second order. The closeness and uniformity of axial residual stress distribution curve compared to the hoop residual stress distribution curve is representative of more balanced behavior of these stresses distribution.}, Keywords = {Residual stress,Pipe girth welding,Hole drilling strain gage test,HSLA,Spline and approximating polynomials,}, volume = {18}, Number = {7}, pages = {226-232}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-13231-en.html}, eprint = {http://mme.modares.ac.ir/article-15-13231-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} } @article{ author = {Honarmand, Mehrdad and Moradi, Mehr}, title = {Investigation of mechanical behavior of perfect nano-garphene sheets and defected ones by Scaled boundary finite element method}, abstract ={For the first time in this paper, by using semi-analytical scaled boundary finite element method (SBFM), a perfect nano garphene sheet or defected ones were simulated and their mechanical behavior had been investigated. In this analysis, the atomic carbon bonds were modeled by simple bar elements with circular cross- sections and then the scaled boundary finite element relations were formulated based on the geometry of the model. The obtained results from SBFM were compared to those obtained from molecular dynamic method which showed that the SBFM can be used as a continuum mechanics model with high accuracy in mechanical analysis of both perfect and defected nano graphene sheets. Existence of structural defects in nano grapheme sheets decrease the strength as well as fracture strain in a considerable manner. It can be noted that in a defected nano grapheme sheet, the fracture stress decreases more than 34% while fracture strain decreases more than 50%. In the cases that instead of using bar elements, whole area is considered as a continuum sheet and in order to obtain a similar geometry to those problems have bar elements, no material zone be modeled by zero elastic properties, the results show considerable errors.}, Keywords = {Scaled boundary finite element,Nano graghene sheets,Defected,Mechanical behavior,Molecular dynamics,}, volume = {18}, Number = {7}, pages = {233-239}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-16743-en.html}, eprint = {http://mme.modares.ac.ir/article-15-16743-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} } @article{ author = {damadipour, majid and Tarinejad, Reza and Aminfar, Mohammad Hossei}, title = {Operational modal analysis based on the power spectral density transmissibility matrix obtained from the short seismic records with different noise levels}, abstract ={In recent years, a new approach called transmissibility based operational modal analysis has been propounded.The new approach is able to identify the modal parameters of structural systems based on the transmissibility functions, where, unlike conventional methods of operational modal analysis, there is no limiting assumption about the input excitations. In this paper, an effective form of transmissibility called power spectral density transmissibility is used in order to identify the dynamic characteristics of a 5DOF system. The dynamic system that is modeled using MATLAB/Simulink is excited by the different earthquakes such as El Centro, Northridge and Loma Prieta, and white Gaussian noise is also added to its responses with different signal to noise ratios. The modal parameters (natural frequencies and mode shapes) of the numerical model are calculated and extracted based on the singular values and vectors obtained from singular value decomposition of the power spectral density transmissibility matrix. This matrix, unlike the Fourier spectral transmissibility matrix, can be created based on the transferring outputs obtained from just one loading condition; therefore, there is no need to use the outputs of multiple loading conditions, so that it is possible to identify the dynamic characteristics with only one dynamic test. In this research, the modal identification results are evaluated through comparison with the values obtained from exact solution of the system. The comparison shows that the modal parameters extracted from the system responses with different noise levels have a good agreement with the exact values.}, Keywords = {Transmissibility based operational modal analysis,Power spectral density transmissibility,white Gaussian noise,Singular value decomposition,Fourier spectral transmissibility,}, volume = {18}, Number = {7}, pages = {240-250}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-16771-en.html}, eprint = {http://mme.modares.ac.ir/article-15-16771-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} } @article{ author = {Kazeminia, Sarang and AbdiBehnagh, Reza and Kalabkhani, Mil}, title = {Design and Manufacturing of a Low-Power Dual-Axis Sun Tracker Based on Novel Mechanical and Electrical Detectors}, abstract ={In this paper the conventional structure of dual-axis sun tracker is modified based on new mechanical and electrical detectors which are proposed to reduce both the angular error and power consumption. Automatic adjustment of the azimuth, latitude and altitude angle for the photovoltaic panels improves the performance of converting solar energy to the electrical energy, throughout all the seasons. In other words, both the north-worth and east-west angular error is continuously minimized until that the panel’s surface is solarized with the maximum energy. Post-Fabrication results show that the proposed control circuit and two actuators consume the average power of less than 10mWatt alongside the 13-hour of a summer day. The external power source is no longer required because the received power is saved in a battery in order to provide the power of the control circuit. The ratio of the required energy to the saved energy is optimized to around 0.13%. Measurement results confirm that the total Watt-hour during a summer day is improved around 60 percent in comparison to the case that a fixed panel is used. Design of the mechanical objects are performed using CATIA software such that endure up to 1200Watt panel array.}, Keywords = {Mechatronic Systems,Sun Tracker,Dual-Axis Sun Tracker,Green Energies,Renewable Energies,}, volume = {18}, Number = {7}, pages = {251-259}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-16101-en.html}, eprint = {http://mme.modares.ac.ir/article-15-16101-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} } @article{ author = {Khayyami, Mohammad Javad and ShateriNajafAbadi, Alireza and doustdar, mohammadmahdi}, title = {Evaluation the Effect of Using Two Fuel Nozzles on Droplet Diameter in Cross Flow}, abstract ={The purpose of this study is to investigate the effect of the simultaneous use of fuel injection injectors in an air cross flow. Nowadays, several methods are proposed for optimizing fuel injection in internal combustion engines. These optimizations are due to the high impact of this variable on engine performance and reduction of emissions. The method proposed in this study is to use two fuel injectors instead of a single injector in the air inlet manifold. The uses of two injectors in order to impingement two fuel sprays and increase the turbulent and collision of droplets, and so break them up faster. Also, the use of two injectors can provide more control over spatial and temporal distribution. Simulations are performed numerically using the generalized Kiva code. These simulations are similar to the fuel injection conditions in the manifold of the spark ignition internal combustion engine. The results indicate that the placement of two injectors in a longitudinal distance, the installation of two injectors at a 70 ° angle with the duct, placing two injectors in 180° or 90° relative angles and a 15° conical angle reduces the average diameter of the droplets. The results of this study can be used to design an internal combustion engine fuel injection system.}, Keywords = {Internal combustion engine,Fuel injection,Injector,Fuel spray simulation,Cross flow,}, volume = {18}, Number = {7}, pages = {260-266}, publisher = {Tarbiat Modares University}, url = {http://mme.modares.ac.ir/article-15-15494-en.html}, eprint = {http://mme.modares.ac.ir/article-15-15494-en.pdf}, journal = {Modares Mechanical Engineering}, issn = {1027-5940}, eissn = {2476-6909}, year = {2018} }