Materials and Energy Research CenterInternational Journal of Engineering1025-249524320110901Static and dynamic nonlinear analysis of steel frame with semi-rigid connections20322271913ENMohsen BambaeecheeCivil Engineering Department, Engineering Faculty, Quchan University of Advanced Technology0000-0002-9970-6868M. Rezaiee Pajand0000-0002-8808-0011S.R. SarafraziCivil Engineering Department, Birjand UniversityJournal Article19700101One of the important issues in the study of steel frames is to find a suitable formulation for semi-rigid connections. In this paper, the explicit stiffness matrix for a two-dimensional beam-column element having end-flexibilities is derived. The effects of the lateral uniformly distributed load on the deflection are considered. Both tensile and compressive axial loads are also taken into account by one formula. By using the proposed stiffness matrix, some first-order, second-order, buckling, and dynamic analyses for semi-rigid frames are performed. The plastic analysis is also carried out using the plastic hinge approach. Comparing the calculated results with other references shows the accuracy and capabilities of the new element. Furthermore, the influences of the semi-rigid connections on the static and dynamic responses are investigated.Materials and Energy Research CenterInternational Journal of Engineering1025-249524320110901Nonlinear sensitivity Analysis of RCMRF Considering Both Axial and Flexure Effects (RESEARCH NOTE)22323871915ENAlireza HabibiCivil Engineering, University of KurdistanJournal Article19700101 Sensitivity analysis of structures considering their nonlinear behavior has recently been an important process in optimal design of them based on new design concepts such as Performance-Based Design (PBD). The main objective of this research is to develop an efficient and applicable method for nonlinear sensitivity analysis of Reinforcement Concrete Moment Resisting Frames (RCMRF) accounting for both axial and flexure effects under seismic loading. For this purpose, sensitivity equations are firstly derived based on pushover method, which is a powerful tool for nonlinear analysis of structures in the PBD context, and then a procedure for nonlinear sensitivity analysis is proposed. The results of the method are compared with nonlinear sensitivity results considering only flexural effect and those of Finite Difference Method (FDM). It is shown that existence of axial forces can affect sensitivity coefficients with respect to some design variables.Materials and Energy Research CenterInternational Journal of Engineering1025-249524320110901Performance Modeling of Power Generation System of a Thermal Plant23924871918ENSORABH GUPTAADMINISTRATION, RPIIT KARNALP.C Tewari, National Institute of Technology, Kurukshetra.Journal Article19700101The present paper discusses the development of a performance model of power generation system of a thermal plant for performance evaluation using Markov technique and probabilistic approach. The study covers two areas: development of a predictive model and evaluation of performance with the help of developed model. The present system of thermal plant under study consists of four subsystems with three possible states: full working, reduced capacity working and failed. Failure and repair rates for all the subsystems are assumed to be constant. A transition diagram represents the operational behavior of the system. A probabilistic model has been developed, considering some assumptions. Data in feasible range are selected from a survey of thermal plant and the effect of each subsystem on the system availability is tabulated in the form of availability matrix, which provides various performance/availability levels for different combinations of failure and repair rates of all subsystems.Materials and Energy Research CenterInternational Journal of Engineering1025-249524320110901Solving a new bi-objective model for a cell formation problem considering labor allocation by multi-objective particle swarm optimization24925871919ENMohammad KhazaeiDepartment of Industrial Engineering, University of Pyam NoorA. MakuiDepartment of Industrial Engineering, Iran University of Science and Technology (IUST)Reza Tavakkoli-MoghaddamIndustrial Engineering, University of Tehran0000-0002-6757-926XAli GhodratnamaIndustrial Engineering, Kharazmi UniversityJournal Article19700101Mathematical programming and artificial intelligence (AI) methods are known as the most effective and applicable procedures to form manufacturing cells in designing a cellular manufacturing system (CMS). In this paper, a bi-objective programming model is presented to consider the cell formation problem that is solved by a proposed multi-objective particle swarm optimization (MOPSO). The model contains two conflicting objectives, namely optimal labor allocation and maximization of cell utilization. The related results of the proposed MOPSO are compared with the results obtained by a well-known evolutionary procedure, called NSGA-II, in order to verify its effectiveness.Materials and Energy Research CenterInternational Journal of Engineering1025-249524320110901Minimizing the supplying cost of leverage items: a mathematical approach25927471921ENJ. RazmiIndustrial Engineering, University of TehranA. KeramatiIndustrial Engineering, University of TehranJournal Article19700101In the new competitive environment, selecting and planning of the supply chain is very crucial and involves evaluation of many factors. Different approaches have been applied to assess the supplier/s. Most of these studies are based upon the supplier/s' capabilities. It may be neither rational nor economical to deal with each item via a generic material control system. Furthermore, supplier/s selection not only depends on suppliers' capability, but also depends on the nature and characteristics of the parts. Little attention is given to decisions on the appropriate selecting of supplier/s, and assigning order quantities to them, especially, in case of multiple sources considering their performance and materials’ characteristics. In this paper two models are presented which locate the optimal supplier/s regarding supplier/s' capabilities and materials’ characteristics for leverage items based on references [1 and 2]. The first one is a G.P. model which considers constraints of lead-time, quality, demand, supplier/s capacity and budgets in a dynamic condition. The second one considers the problem in a contingent environment and considers criteria with normal distributions. Each model follows by an illustrative numerical example and sensitivity analysis which demonstrate the effectiveness and validation of the modelMaterials and Energy Research CenterInternational Journal of Engineering1025-249524320110901Side Effects of Shot Peening on Fatigue Crack Initiation Life27528071924ENS.M. H-GangarajMech Eng, Sharif Univ. of TechnologyG. H. FarrahiSchool of Mechanical Engineering, Sharif University of Technologyhttps://orcid.org/00Journal Article19700101Shot peening beneficial effects on fatigue life of mechanical components are well known. However, there are some reports in the literature that indicate inappropriate shot peening parameters tend to reduce the fatigue life. It is therefore, the purpose of this study to find a logical quantitative justification for these observations. Using finite element method, a dynamic elastic-plastic simulation of shot peening was presented. Effect of shot velocity and size on surface morphology after shot peening were examined. Fatigue crack initiation life calculation of shot peened specimens revealed that beneficial effect of shot peening significantly vanishes in the case of high velocities and bigger shots.Materials and Energy Research CenterInternational Journal of Engineering1025-249524320110901Effects of Geometric Nonlinearity on Stress Analysis in Large Amplitude Vibration of thin Circular Functionally Graded Plates With Rigid Core28129071926ENM. H. PashaeiDepartment of solid Mechanics, Babol Noshirvani University of TechnologyFarshad FotrosMechanical Engineering, Babol Noshirvani University of TechnologyM.H. NaeiMechanical Engineering, University of TehranJournal Article19700101Abstract In this paper , the nonlinear the nonlinear free and forced axisymmetric vibration of a thin circular functionally graded plate with rigid core is formulated in terms of von-Karman’s dynamic equation , and a semi-analytical approach is developed.Functionally graded material (FGM) properties vary through the thickness of the plate.FGM s are spatial composites within which material properties vary continuously and inhomogeneously.This problem is solved with MATLAB code.The mass of the core respect to the mass of plate is negligible. For verification, a solved coreless FGM circular plate has been solved by this code. The results show a good approximation. The results reveal that vibration amplitude and volume fraction have significant effects on the resultant stresses in large amplitude vibration of the functionally graded plate with rigid core.Materials and Energy Research CenterInternational Journal of Engineering1025-249524320110901Pareto Optimization of a Two-degree of Freedom Passive Linear Suspension Using a New Multi-objective Genetic Algorithm (TECHNICAL NOTE)29130071927ENHamid RostamiMech Eng, Azad University-Takestan BranchAhmad BagheriMechanical Engineering, University of GuilanMohammad Javad MahmoodabadiMechanical Engineering, Sirjan University of TechnologyShahram KheybariIndustrial Engineering, Khatam universityJournal Article19700101The primary function of a suspension system of a vehicle is to isolate the road excitations experienced by the tires from being transmitted to the passengers. In this paper, we formulate an optimal vehicle suspension design problem with the quarter-car vehicle dynamic model. A new multi-objective genetic algorithm is used for Pareto optimization of a two-degree of freedom vehicle vibration model considering the two conflicting functions simultaneously. The important conflicting objective functions that have been considered in this work are, namely, sprung mass acceleration and relative displacement between sprung mass and tire. The comparison of the obtained results with those in the literature demonstrates the superiority of the results of this work. It is shown that the results of 2-objective optimization provide more non-dominated choices for designers to select appropriate choices regarding the condition and purpose of using a vehicle in order to optimal design of a product.Materials and Energy Research CenterInternational Journal of Engineering1025-249524320110901Numerical simulation of a three-layered radiant porous heat exchanger including lattice Boltzmann simulation of fluid flow30131971929ENSaeed JafariMechanics, Shahid Bahonar UniversityS.A. Gandjalikhan NassabMechanical Engineering, Shahid Bahonar University of KermanEbrahim JahanshahiMechanics, Shahid Bahonar UniversityJournal Article19700101This paper deals with the hydrodynamic and thermal analysis of a new type of porous heat exchanger (PHE). This system operates based on energy conversion between gas enthalpy and thermal radiation. The proposed PHE has one high temperature (HT) and two heat recovery (HR1 and HR2) sections. In HT section, the enthalpy of flowing high temperature gas flow that is converted to thermal radiation emitted towards the two heat recovery sections in which the reverse energy conversion from thermal radiation to gas enthalpy takes place. In each section, a 2-D rectangular porous segment which is assumed to be absorbing, emitting and scattering is presented. For theoretical analysis of the PHE, the gas and solid are considered in non-local thermal equilibrium and separate energy equations are used for the two phases. Besides, in the gas flow simulation, the lattice Boltzmann method (LBM) is applied to obtain the velocity distribution through the porous segments. For the purpose of thermal analysis of the proposed PHE, volume-averaged velocities through the porous matrix obtained by LBM are used in the gas energy equation and then the coupled energy equations for gas and porous medium of each section are numerically solved using finite difference method. The radiative transfer equation is solved by discrete ordinates method to calculate the distribution of radiative heat flux in the porous medium. The numerical results consist of the gas and porous temperature distributions and also the variation of radiative heat flux are presented. Furthermore, the effects of scattering albedo, optical thickness and inlet gas temperature on the efficiency of the proposed PHE are investigated. It is revealed that this type of heat exchanger has high efficiency in comparison to conventional one. Also, the present numerical results for a porous radiant burner are compared with theoretical finding by the other investigator and good agreement is found.