Shahid Rajaee Teacher Training University (SRTTU)Journal of Computational & Applied Research in Mechanical Engineering (JCARME)2228-79222220130303Heat generation and radiation effects on steady MHD free convection flow of micropolar fluid past a moving surface1104810.22061/jcarme.2013.48ENM.Gnaneswara ReddyDepartment of Mathematics, Acharya Nagarjuna University, Ongole Campus,Ongole 523 001, IndiaJournal Article20111003This paper was concerned with studying the magnetohydrodynamic steady laminar free convection flow of a micropolar fluid past a continuously moving surface in the presence of heat generation and thermal radiation. Similarity transformation was employed to transform the governing partial differential equations into ordinary ones, which were then solved numerically using the finite element method. Numerical results for the dimensionless velocity, microrotation and temperature profiles were obtained and displayed graphically for pertinent parameters to show interesting aspects of the solution. The skin friction and the rate of heat transfer were also computed and presented through tables. Favorable comparison with previously published work was performed.https://jcarme.sru.ac.ir/article_48_849091d084b844acecfc25c13889c932.pdfShahid Rajaee Teacher Training University (SRTTU)Journal of Computational & Applied Research in Mechanical Engineering (JCARME)2228-79222220130303Experimental investigations on the softening and ratcheting behaviors of steel cylindrical shell under cyclic axial loading11224910.22061/jcarme.2013.49ENM.ShariatiMechanical Engineering Faculty, Shahrood University of Technology, Shahrood, Semnan, IranDepartment of Mechanical Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad,
IranH.HatamiMechanical Engineering Faculty, Semnan University, Semnan, IranM.Damghani NouriMechanical Engineering Faculty, Semnan University, Semnan, IranJournal Article20120524In this research, softening and ratcheting behaviors of Ck20 alloy steel cylindrical shells were studied under displacement-control and force-control cyclic axial loading and the behavior of hysteresis curves of specimens was also investigated. Experimental tests were performed by a servo-hydraulic INSTRON 8802 machine. The mechanical properties of specimens were determined according to ASTM E8 standard. Under force-control loading with non-zero mean force, ratcheting behavior occurred on cylindrical shell and plastic strain accumulation continued up to the collapse point of cylindrical shell. The rate of ratcheting strain became higher using the higher force amplitude. Softening behavior was observed under displacement control loading and, due to the occurred buckling in compression zone, this behavior became more extreme. The behavior of hysteresis curves of this alloy was not symmetrical under tensile and compressive loads. Moreover, the influence of loading history was studied on the behavior of hysteresis curves of the specimens under various types of loadings.https://jcarme.sru.ac.ir/article_49_263a91bdaed289ecc2789748f2c6c817.pdfShahid Rajaee Teacher Training University (SRTTU)Journal of Computational & Applied Research in Mechanical Engineering (JCARME)2228-79222220130303Generalized solution of functionally graded hollow cylinder under torsional load23325010.22061/jcarme.2013.50ENY.BayatYoung Researchers Club, Mashhad Branch, Islamic Azad University, Mashhad, IranM.AlizadehDepartment of Mechanical Engineering, Iran University of Science & Technology, Tehran, IranA.BayatDepartment of Mechanical Engineering Isfahan University of Technology, Isfahan, IranJournal Article20120607In this paper, a general solution for torsion of hollow cylinders made of functionally graded materials (FGM) was investigated. The problem was formulated in terms of Prandtl’s stress and, in general, the shear stress and angle of twist were derived. Variations in the material properties such as Young’s modulus and Poisson’s ratio might be arbitrary functions of the radial coordinate. Various material models from the literature were also used and the corresponding shear stress and angle of twist were individually computed. Moreover, by employing ABAQUS simulations, finite element results were compared with the analytical ones.https://jcarme.sru.ac.ir/article_50_395593cb2e9607c2c10a35359c2a2a78.pdfShahid Rajaee Teacher Training University (SRTTU)Journal of Computational & Applied Research in Mechanical Engineering (JCARME)2228-79222220130303Influence of varying timing angle on performance of an SI engine: An experimental and numerical study33435110.22061/jcarme.2013.51ENA. H.KakaeeDepartment of Automotive Engineering, Iran University of Science and Technology, IranJ.ZareeiEngineering Center for Technical Drawing, Sharif University of Technology, IranJournal Article20120929Engine performance depends on two main factors of engine speed and ignition time. Ignition timing can affect engine life, fuel economy and engine power. In this paper, to study engine performance of Peugeot 206 TU3A with comparison ratio of 10.5:1 and displacement of 1361CC in MATLAB software, a two-zone burned/unburned model with the fuel burning rate described by aWiebe function was used for modeling in-cylinder combustion. For studying this issue, thermodynamic models such as Woshni, Isentropic, etc. were used. Then, the experiments were carried out to validate the calculated data. The objective of the present work was to examine effect of ignition timing on the performance of an SI engine. For achieving this goal, at the speed of 3400 rpm, ignition timing was changed in the range of 41 degrees before the top dead centre to 10 degrees after TDC. By changing the ignition timing, the results of some characteristics such as power, torque, indicatory pressure, exhaust emission and efficiency were obtained and compared. The results demonstrated that optimal power and torque and the maximum efficiency were achieved at 31 degrees before the top dead centre and engine performance was improved by changing timing angle. It was also indicated that the maximum thermal efficiency could be accomplished while peak pressure occurred between 5 and 15 degrees of ATDC. The amounts of O<sub>2</sub>, CO<sub>2</sub> and CO were almost constant but HC increased with increase of ignition timing.https://jcarme.sru.ac.ir/article_51_0636b99806ddcb14acc59bfe6937c7e0.pdfShahid Rajaee Teacher Training University (SRTTU)Journal of Computational & Applied Research in Mechanical Engineering (JCARME)2228-79222220130303Approximate solution of laminar thermal boundary layer over a thin plate heated from below by convection45575210.22061/jcarme.2013.52ENAminrezaNoghrehabadiDepartment of Mechanical Engineering, Shahid Chamran University of Ahvaz, Ahvaz, IranMohammadGhalambazDepartment of Mechanical Engineering, Shahid Chamran University of Ahvaz, Ahvaz, IranAminSamimiDepartment of Mechanical Engineering, Shahid Chamran University of Ahvaz, Ahvaz, IranJournal Article20120430In this paper, an integration of a symbolic power series method - Padé approximation technique (PS - Padé), was utilized to solve a system of nonlinear differential equations arising from the similarity solution of laminar thermal boundary layer over a flat plate subjected to a convective surface boundary condition. As both boundary conditions tended to infinity, the combination of series solutions with the Padé approximants was used for handling boundary conditions on the semi-infinite domain of solution. The combination of power series and Padé proposed an alternative approach of solution which did not require small parameters and avoided linearization and physically unrealistic assumptions. The results of the present approach were compared with numerical results as well as those of previous works reported in the literature. The obtained results represented remarkable accuracy in comparison with the numerical ones. Finally, reduced Nusselt number, as an important parameter in heat transfer, was calculated by the obtained analytical solution. The present power series-Padé technique was very simple and effective, which could develop a simple analytic solution for flow and heat transfer over the flat plate. The results of the present study could be easily used in practical applications.https://jcarme.sru.ac.ir/article_52_d7ea1a756aa2bf6593c2c1742c13af87.pdfShahid Rajaee Teacher Training University (SRTTU)Journal of Computational & Applied Research in Mechanical Engineering (JCARME)2228-79222220130303Construction of solitary solution and compacton-like solution by the variational iteration method using He's polynomials59685310.22061/jcarme.2013.53ENM.MatinfarFaculty of Mathematics Science, Department of Mathematics, Mazandaran University,
P.O.Box 47415-95447, Babolsar, IranM.GhasemiFaculty of Mathematics Science, Department of Mathematics, Mazandaran University,
P.O.Box 47415-95447, Babolsar, IranJournal Article20120105Variational Iteration method using He's polynomials can be used to construct solitary solution and compacton-like solution for nonlinear dispersive equatioons. The chosen initial solution can be determined in compacton-like form or in solitary form with some compacton-like or solitary forms with some unknown parameters, which can be determined in the solution procedure. The compacton-like solution and solitary solution can be converted into each other.https://jcarme.sru.ac.ir/article_53_7f50d006dc04795e664138da2aefb5f9.pdfShahid Rajaee Teacher Training University (SRTTU)Journal of Computational & Applied Research in Mechanical Engineering (JCARME)2228-79222220130303Finite element comparison of single, bi-layered and three-layered tube hydroforming processes69805410.22061/jcarme.2013.54ENGh.PayganehDepartment of Mechanical Engineering, Shahid Rajaee Teacher Training University (SRTTU), Tehran, IranJ.Shahbazi KaramiDepartment of Mechanical Engineering, Shahid Rajaee Teacher Training University (SRTTU), Tehran, IranK.Malekzadeh FardSpace research institute, 26th Kilometer of Expressway of Tehran-Karaj, Tehran, IranJournal Article20120911In this paper, single, bi-layered and three-layered tube hydroforming processes were numerically simulated using the finite element method. It was found that the final bulges heights resulted from the models were in good agreement with the experimental results. Three types of modeling were kept with the same geometry, tube material and process parameters to be compared between the obtained hydroformed products (branch height, thickness reduction and wrinkling) using different loading path types. The results were also discussed.https://jcarme.sru.ac.ir/article_54_1421a1e7a10a80041783100ee307258f.pdf