Shahid Chamran University of AhvazJournal of Applied and Computational Mechanics2383-45361120140601Nonlinear transversely vibrating beams by the homotopy perturbation method with an auxiliary term191054510.22055/jacm.2014.10545ENHamid M.SedighiShahid Chamran University, Faculty of Engineering, Mechanical Engineering Department, Ahvaz, Iran0000-0002-3852-5473FarhangDaneshmandDepartment of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2K6Journal Article20140318This paper presents the high order frequency-amplitude relationship for nonlinear transversely vibrating beams with odd and even nonlinearities, using Homotopy Perturbation Method with an auxiliary term (HPMAT). The governing equations of vibrating buckled beam, beam carrying an intermediate lumped mass, and quintic nonlinear beam are investigated to exhibit the reliability and ability of the proposed asymptotic approach. It is demonstrated that two terms in series expansions are sufficient to obtain a highly accurate periodic solutions. The integrity of the analytical solutions is verified by numerical results.https://jacm.scu.ac.ir/article_10545_cdeea4bb07f2a3db61cf4e9502de142e.pdfShahid Chamran University of AhvazJournal of Applied and Computational Mechanics2383-45361120140601Optimal Roll Center Height of Front McPherson Suspension System for a Conceptual Class A Vehicle10161057810.22055/jacm.2014.10578ENJavadMeshkatifarMaster Student, Department of Mechanical Engineering, Isfahan University of TechnologyMohsenEsfahanianAssociate Professor, Department of Mechanical Engineering, Isfahan University of TechnologyJournal Article20140421In this paper, the effects of roll center height of McPherson suspension mechanism on dynamic behaviour of a vehicle are first studied, and then the optimum location of roll center of this suspension system is determined for a conceptual Class A vehicle. ADAMS/Car software was used for the analysis of vehicle dynamic behaviour in different positions of suspension roll center. Next, optimization process has been done using ADAMS/Insight. Results show significant effects of roll center location on body roll angle, body roll rate and steering response. Also, the contradiction between body roll and steering response can be observed.https://jacm.scu.ac.ir/article_10578_3cdaf7097bd9f98624ec26e839b070d2.pdfShahid Chamran University of AhvazJournal of Applied and Computational Mechanics2383-45361120140601Pull-in behavior analysis of vibrating functionally graded micro-cantilevers under suddenly DC voltage17251055210.22055/jacm.2014.10552ENJamalZareNational Iranian South Oil Company (NISOC), Ahvaz, IranJournal Article20140203The present research attempts to explain dynamic pull-in instability of functionally graded micro-cantilevers actuated by step DC voltage while the fringing-field effect is taken into account in the vibrational equation of motion. By employing modern asymptotic approach namely Homotopy Perturbation Method with an auxiliary term, high-order frequency-amplitude relation is obtained, then the influences of material properties and actuation voltage on dynamic pull-in behavior are investigated. It is demonstrated that the auxiliary term in the homotopy perturbation method is extremely effective for higher order approximation and two terms in series expansions are sufficient to produce an acceptable solution. The strength of this analytical procedure is verified through comparison with numerical results.https://jacm.scu.ac.ir/article_10552_dc1efb081b26fc82c7ab2c8edeb51aa1.pdfShahid Chamran University of AhvazJournal of Applied and Computational Mechanics2383-45361120140601Global Finite Time Synchronization of Two Nonlinear Chaotic Gyros Using High Order Sliding Mode Control26341054910.22055/jacm.2014.10549ENMohammad RezaBehjamehFaculty of Electrical and Electronic Engineering, Department of Control Engineering, Malek Ashtar University of TechnologyHadiDelavariAssistant Professor, Department of Electrical and Electronic Engineering, Hamedan University of TechnologyAhmadrezaValiAssistant Professor, Faculty of Electrical and Electronic Engineering, Department of Control Engineering, Malek Ashtar University of TechnologyJournal Article20140427In this paper, under the existence of system uncertainties, external disturbances, and input nonlinearity, global finite time synchronization between two identical attractors which belong to a class of second-order chaotic nonlinear gyros are achieved by considering a method of continuous smooth second-order sliding mode control (HOAMSC). It is proved that the proposed controller is robust to mismatch parametric uncertainties. Also it is shown that the method have excellent performance and more accuracy in comparison with conventional sliding mode control. Based on Lyapunov stability theory, the proposed controller and some generic sufficient conditions for global finite time synchronization are designed such that the errors dynamic of two chaotic behaviour satisfy stability in the Lyapunov sense. The numerical results demonstrate the efficiency of the proposed scheme to synchronize the chaotic gyro systems using a single control input.https://jacm.scu.ac.ir/article_10549_077192115381693b0d840d62b92b3586.pdfShahid Chamran University of AhvazJournal of Applied and Computational Mechanics2383-45361120140601Bearing Fault Detection Based on Maximum Likelihood Estimation and Optimized ANN Using the Bees Algorithm35431054710.22055/jacm.2014.10547ENBehroozAttaranMSc., Mechanical Engineering, Shahid Chamran University of Ahvaz0000-0002-2323-4673AfshinGhanbarzadehAssistant Professor, Mechanical Engineering Department, Shahid Chamran University of Ahvaz0000-0002-5197-9752Journal Article20140505Rotating machinery is the most common machinery in industry. The root of the faults in rotating machinery is often faulty rolling element bearings. This paper presents a technique using optimized artificial neural network by the Bees Algorithm for automated diagnosis of localized faults in rolling element bearings. The inputs of this technique are a number of features (maximum likelihood estimation values), which are derived from the vibration signals of test data. The results show that the performance of the proposed optimized system is better than most previous studies, even though it uses only two features. Effectiveness of the above method is illustrated using obtained bearing vibration data.https://jacm.scu.ac.ir/article_10547_decbdc01b7f1970b36a9b83382e1f020.pdfShahid Chamran University of AhvazJournal of Applied and Computational Mechanics2383-45361120140601Determination of Periodic Solution for Tapered Beams with Modified Iteration Perturbation Method44511072910.22055/jacm.2014.10729ENMohammad MehdiMashinchi JoubariDept. of Mechanical Engineering, Babol University of Technology, Babol, IranDavood DomiriGanjiAssistant Professor, Department of Mechanical Engineering, Babol University of Technology, Babol, IranHamidJavanian JouybariDepartment of Mechanical Engineering, Semnan University, IranJournal Article20140616In this paper, we implemented the Modified Iteration Perturbation Method (MIPM) for approximating the periodic behavior of a tapered beam. This problem is formulated as a nonlinear ordinary differential equation with linear and nonlinear terms. The solution is quickly convergent and does not need complicated calculations. Comparing the results of the MIPM with the exact solution shows that this method is effective and convenient. Also, it is predicated that MIPM can be potentially used in the analysis of strongly nonlinear oscillation problems accurately. https://jacm.scu.ac.ir/article_10729_d9d4b6eb88c9bf486ec1ad1fad40136f.pdf