Materials and Energy Research CenterInternational Journal of Engineering1025-249528320150301Ultrasonic and Microwave Pretreatment for Hydrothermal Synthesis of Nanosized SAPO-34 and Their Catalytic Performance in MTO Reaction (RESEARCH NOTE)33033772461ENMajid TaghizadehChemical Engineering, Babol Noshirvani University of TechnologyHassan Sharifi PajaieChemical Engineering, Babol University of TechnologyJournal Article19700101In order to enhance the catalytic performance of SAPO-34 catalyst for the reaction of methanol to olefins (MTO), ultrasonic and microwave-assisted aging method were employed in static hydrothermal method to synthesize nano-sized SAPO-34. The effects of the application of this method on the chemical composition, morphology, surface area and total acidity of SAPO-34 were characterized by XRD, FE-SEM, nitrogen adsorption–desorption and NH3-TPD techniques. The catalytic performance of synthesized SAPO-34 was investigated for MTO reaction in a fixed-bed reactor under the same operating conditions (T = 450 °C, P =1 atm, and WHSV = 4 h−1). Comparing with the SAPO-34 synthesized with conventional hydrothermal method, sample synthesized with simultaneous use of US and MW-assisted aging methods possesses larger surface area and small crystal size and exhibits higher selectivity to light olefins (C˭2-C˭4) and longer lifetime. Materials and Energy Research CenterInternational Journal of Engineering1025-249528320150301A Continuum Shell-beam Finite Element Modeling of Buried Pipes with 90-degree Elbow Subjected to Earthquake Excitations33834972462ENM. VafaeianCivil Engineering, Isfahan University of TechnologyMiad SaberiCivil Engineering, Isfahan University of TechnologyJournal Article19700101 In the current work, the seismic analysis of bent region in buried pipes is performed, and effects of soil properties and modeling methods on pipe’s response are investigated. To do this task Beam, Beam-Shell Finite Element modeling and a Continuum shell FE models of a 90 degrees elbow are employed. In the Beam model, the pipe is simulated by beam elements while combined shell-beam elements are used for the Continuum shell finite element model. The surrounding soil is simulated by nonlinear spring and solid elements; moreover, soil hardening behavior and soil-pipe slippage are considered in the models. In addition, an equivalent boundary condition has been employed at the end of each elbow leg to simulate far field effects more closely. From these analyses, it can be revealed that axial strain at bends is larger in stiffer soil due to smaller slippage. In addition, a full three dimensional soil-pipe interaction using Continuum Shell FE model causes a substantial increase of elbow strain.Materials and Energy Research CenterInternational Journal of Engineering1025-249528320150301Ultimate Unbonded Tendon Stress in CFRP Strengthened Post-Tensioned Indeterminate I-Beams Cast with HSCs35035972463ENAli MaghsoudiCivil Engineering, University of KermanYousef Askari D.Department of Civil Engineering, Shahid Bahonar UniversityJournal Article19700101Based on the bending experiment for two-span continuous post-tension beams with unbounded tendons and externally applied CFRP sheets, the analysis of the stress increment of unbonded tendons is monitored in the loading process. Since self-compacting concrete (SCC) is a suitable innovation,, understanding the implementation of this type of concrete on the ultimate unbonded tendon stress is critical. For these aims, results of four continuous un-bonded post-tensioned I-beams in two groups were cast and monitored by electrical strain gauges andare presented here. In the first group, the beams (UPN1-12, SUPN1-12) consisted of high strength normal concrete (HSNC), while in the second group (UPS1-12, SUPS1-12) high strength self-compacting concrete (HSSCC) were tested. The beams are made which are compared with the theory proposed by different codes, and a preliminary modification is given for each code equation. The results of standard error of estimate Sy/x , indicates that for two types of HSCs (strengthened and non-strengthened beams), the ACI 318-2011 provides better estimates than AASHTO-2010 model, whereas this model provides better estimates as compared toBS 8110-97.Comparison of increase in experimental ultimate tendon stress of beams indicates that the increase in tendon stress at ultimate state in strengthened beams is lower than that in non-strengthened beams cast with HSCs.Materials and Energy Research CenterInternational Journal of Engineering1025-249528320150301Predicting Shear Stress Distribution in Rectangular Channels Using Entropy Concept36036772464ENHossein BonakdariCivil Engieering, Razi UniversityMohtaram TooshmalaniCivil Engieering, Razi UniversityJournal Article19700101This study makes use of the Tsallis entropy to predict the shear stress distribution. Given a definition of the Tsallis entropy, it is maximized by using the probability density function, which then is used to attain a novel shear stress equation. This is then employed for calculating the shear stress distribution in rectangular channels in different aspect ratios and finally, for viability, these calculations are compared with some relevant experimental results. This derived shear stress equation is capable of describing the variation of shear stress in both the wall and the bed of channels. The comparison shows that this equation appears to be efficient for predicting the shear stress distribution in rectangular open channels. Mean values of the bed and wall shear stress calculated by the proposed equation have good agreement with the experiments. The shear force percentage calculated from the equation is in good accordance with the experimental measurements.Materials and Energy Research CenterInternational Journal of Engineering1025-249528320150301Experimental Investigation of the Effect of Splitter Plate Angle on the Under-Scouring of Submarine Pipeline Due to Steady Current and Clear Water Condition36837772465ENMohammad Javad EmamgholizadehCivil Engieering, Sahand University of TechnologyAhmadreza Mostafa GharabaghiCivil Engieering, Sahand University of TechnologyKarim AbediCivil Engieering, Sahand University of TechnologyMohammad Hossein SedaaghiElectrical Engieering, Sahand University of TechnologyJournal Article19700101Submarine pipelines are appropriate method for transmission of oil and gas from sea bed. Free spans may occur due to the natural uneven seabed or by under-scouring. Vortex Induced Vibration (VIV) can happen in such free spans at high Reynolds number. Resonance occurs if the frequency of vortex shedding is close to the pipeline’s natural frequency leading to its fatigue that can break the pipeline causing economical and environmental losses. In literature, there are different methods for suppressing the vortex shedding and pipeline vibration and consequent scouring under the pipe such as the usage of splitter plates. In this paper, the effect of splitter plate’s angle on the scouring under the pipeline is studied experimentally. For this purpose, a new experimental setup is designed and constructed in order to allow for the cylinder to vibrate in both in-line and cross flow directions over an erodible bed. The reduced velocity for the experiments is in the range of 2.45-5.06 and gap ratio is zero. Experimental results indicate that the relative scour depth is reduced with increasing the ratio of gap to pipe diameter. By comparing between relative frequency and reduce velocity, we can conclude that the relative frequency gives a constant value for a large air gap ratio ( ) and also, the pipe has not more effect on the bed. Finally, the scouring depth below the mean location of vibration related to the pipes with a splitter plate and angles 0-30 degrees are less than those without a splitter plate. While, inversely, the scouring depth related to the pipes with a splitter plate and an angle between 60-90 is more than those without a splitter plate.Materials and Energy Research CenterInternational Journal of Engineering1025-249528320150301Free Vibration Analysis of a Sloping-frame: Closed-form Solution versus Finite Element Solution and Modification of the Characteristic Matrices (TECHNICAL NOTE)37838672466ENAhmad Aftabi SaniCivil Engineering, Islamic Azad Univesity of MashhadDavoud NezamolmolkiCivil Engieering, Ferdowsi University of MashhadJournal Article19700101This article deals with the free vibration analysis and determination of the seismic parameters of a sloping-frame which consists of three members; a horizontal, a vertical, and an inclined member. The both ends of the frame are clamped, and the members are rigidly connected at joint points. The individual members of the frame are assumed to be governed by the transverse vibration theory of an Euler-Bernoulli beam. To solve this classical problem, a closed-form solution is firstly proposed and then, a numerical analysis is performed for some verification purposes. The closed-form solution is developed by solving the frame equations of motion, directly. For this reason, some mathematical techniques are utilized, such as Fourier transform and the well-known complementary solutions. In this way, some differential equations must be solved, and several boundary conditions should be satisfied. Herein, the more accurate derivation of the last boundary condition is the most important challenge of this paper. This boundary condition is expressed as three distinctive versions, and the free vibration parameters of the frame for the three versions are attained. Moreover, these results are obtained by the use of the finite element method. In this comparison process, some differences are observed between the closed-form and the numerical results. This fact motivated us to propose some modifications in the characteristic matrices of the finite element model of the frame. This modification makes the results of the Finite element method similar to the results of the first version of the closed-form solution. Finally, the natural frequencies and mode shapes are presented for a wide range of angles of the sloping member. Also, two particular cases are discussed and their boundary conditions are presented.Materials and Energy Research CenterInternational Journal of Engineering1025-249528320150301Application of Interval-valued Fuzzy Analytic Hierarchy Process Approach in Selection Cargo Terminals, a Case Study38739572467ENHossein BonakdariCivil Engieering, Razi UniversityAkbar JavadiYasser MinatourEbrahim MirzaeiJournal Article19700101Cargo terminals are the gateways for entrance of commodities into the transportation network. Therefore, locating them in optimal location could have a major impact on the cost effectiveness and efficiency of transport, traffic safety and reduction in environmental pollutions. Due to the presence of a large number of parameters involved and the existing uncertainties, decision making in this field is a complex task. If the decision makers cannot reach an agreement on the method of defining linguistic variables based on the fuzzy sets, favorable results and more accurate modeling can be achieved by using the interval-valued fuzzy sets (IVFSs), which provide an additional degree of freedom to represent the uncertainty and fuzziness in the real world. This study presents a group fuzzy analytic hierarchy process (AHP) based on IVFSs (IVF-AHP), and its application to find the optimal location for the Ghaen (Qayenat) cargo terminal in Ghaen City, Iran. The results show that the proposed method is a reliable method in selecting the optimal location for cargo terminals.Materials and Energy Research CenterInternational Journal of Engineering1025-249528320150301Active Suspension System Control Using Adaptive Neuro Fuzzy (ANFIS) Controller39640172468ENFarshad SamadiFaculty of Electrical and Computer Engineering, University of Tabriz, Tabriz-IRANHamid Moghadam-FardFaculty of Electrical and Computer Engineering, University of Tabriz, Tabriz-IRANJournal Article19700101The purpose of designing the active suspension systems is providing comfort riding and good handling in different road disturbances. In this paper a novel control method based on adaptive neuro fuzzy system in active suspension system is proposed. Choosing the proper data base to train the ANFIS has an important role in increasing the suspension system’s performance. The data base which is used to train the proposed ANFIS system is extracted from the outputs of fuzzy, LQR and sliding mode controllers. A quarter-car model is considered to study the performance of the proposed controller. Performance of this controller is compared with the passive system, and active suspension systems with fuzzy and LQR controllers. The results demonstrate that proposed ANFIS controller is better than passive suspension system and active fuzzy and LQR based suspension systems in suspension deflection, body acceleration, settling time and also control force.Materials and Energy Research CenterInternational Journal of Engineering1025-249528320150301Optimal Placement and Sizing of Fault Current Limiter in a Real Network: a Case Study (TECHNICAL NOTE)40240972469ENArman Golzarfar, Yazd Regional Electric CompanyAli Reza SedighiElectrical Engineering, Yazd University0000-0002-1699-2871Abolfazl Asadi, Yazd Regional Electric CompanyJournal Article19700101In this paper, the effect of number and fault current limiter(FCL) location has been investigated in order to have maximum reduction of short circuit current level in all buses in a real network. To do so, the faulty buses were identified in terms of short circuit current level by computing short circuits on the desired network. Then, while the fault current limit was modeled, its optimal location and amount for the greatest reduction in the fault current level of the whole critical buses was determined. Optimization computations have been done using the genetic algorithm and method of reducing the search space and all implementation stages of the proposed algorithm and reduction of search space has been conducted in DIgSILENT software using programming language DPL. The obtained results indicate the high efficiency of the proposed method in reducing the short circuit current level of faulty buses and simultaneous improving the power quality.Materials and Energy Research CenterInternational Journal of Engineering1025-249528320150301Discrete Multi Objective Particle Swarm Optimization Algorithm for FPGA Placement (RESEARCH NOTE)41041872470ENHosna AkbarpourElecctrical, Razi UniversityGholamreza Karimi2Electrical Engineering Department, Razi University of Kermanshah, IranArash SadeghzadehElecctrical, Razi UniversityJournal Article19700101Placement process is one of the vital stages in physical design. In this stage, modules and elements of circuit are placed in distinct locations according to optimization basis. So that, each placement process tries to influence on one or more optimization factor. In the other hand, it can be told unequivocally that FPGA is one of the most important and applicable devices in our electronic world. So, it is vital to spend time to better learning its structure. VLSI science looks for new techniques for minimizing expense of FPGA in order to gain better performance. Diverse algorithms are used for running FPGA placement procedures. It is known that particle swarm optimization (PSO) is one of the practical evolutionary algorithms for this kind of applications. So this algorithm is used for solving placement problem. In this work, a novel method for optimized FPGA placement has been used. According to this process, the goal is to optimize two objectives defined as wire length and overlap removal functions. Consequently, we are forced to use multi-objective particle swarm optimization (MOPSO) in the algorithm. Structure of MOPSO is in a way that introduces set of answers, we have tried to find a unique answer with minimum overlap. This is worth noting that discrete nature of FPGA blocks forced us to use a discrete version of PSO. In fact, we need a combination of multi-objective PSO and discrete PSO for achieving our goals in optimization process. Tested results on some of FPGA benchmark (MCNC benchmark) are shown in “experimental results” section, compared with popular method “VPR”. These results show that proper selection of FPGA’s size and reasonable number of blocks can get us good response.Materials and Energy Research CenterInternational Journal of Engineering1025-249528320150301Low Settling Time All Digital DLL For VHF Application41942572471ENGholamreza ArdeshirElect & Computer Engineering, Babol Nooshirvani University of TechnologyMohammad GholamiElectrical & Electronic Engineering, University of Mazandaran0000-0003-4696-5900Hamid RahimpourElectrical & Computer Engineering, University of Tehran, College of Engineering0000-0003-2096-3536H. MiarNaimiComputer & Electrical Engineering, Babol Noshiravani University of TechnologyJournal Article19700101Settling time is one of the most important parameter in design of DLLs. In this paper we propose a new high speed with low settling time Delay Locked Loop (DLL) in which a digital signal processor (DSP) is used instead of using phase-frequency detector, charge pump and loop filter in conventional DLL. To have better settling time, PRP conjugate gradient algorithm is used to optimize delay of each delay cells. Since this novel architecture has removed phase detector, charge pump and loop filter, the proposed structure shown occupy smaller chip area and has less settling time than conventional DLLs. This method could be implemented in a real system by means a digital signal processor device. Simulation has been done for 15 delay cells and fREF is chosen 14MHz to have output frequency 14×15=210MHz. fOUT=210 MHz is one of the channels in Iran VHF frequency band. As shown with simulations, the proposed architecture has locking time approximately 286nsec which is equal to 4 clock cycles of reference clock.Materials and Energy Research CenterInternational Journal of Engineering1025-249528320150301Fuzzy Approximation Model-based Robust Controller Design for Speed Control of BLDC Motor42643272472ENMahdi ZolfaghariElecrtical Enginnering, Amir Kabir Univ. of Tech.Seyed Abbas TaherElecrtical and Computer Enginnering, Kashan UniversityJournal Article19700101This paper presents a new controller for speed control problem of the BLDC motors. The nonlinear model of the motor is approximated by implementation of fuzzy rules. The uncertainties are considered in the fuzzy system. Using this model and linear matrix inequality (LMI) optimization, a robust controller for purpose of speed control of the motor has been designed and applied to it. The effectiveness of the designed controls demonstrated through simulation results.Materials and Energy Research CenterInternational Journal of Engineering1025-249528320150301A Continuum Model For Stone-wales Defected Carbon Nanotubes43343972473ENBehnam SabooriSchool of Mechanical Engineering, Iran University of Science and Technology (IUST)Hadi Moshrefzadeh-saniSchool of Mechanical Engineering, Iran University of Science and Technology (IUST)Journal Article19700101In this paper, a continuum model is proposed so that a Stone-Wales (SW) defected carbon nanotube (CNT) is replaced by an initial circumferential crack in a continuum cylindrical shell. For this purpose, the critical energy release rate and then the fracture toughness of a defected CNT are calculated using the results of an existing atomistic-based continuum finite element simulation. Finally, the equivalent crack length is obtained from the fracture toughness. The proposed model can be applicable tovarious kinds of continuum-based simulations of nano-structures like nano-composites and nano-probes where the fracture resistance studies become important. It is concluded for a case study that the armchair (12, 12) CNT containing a SW defect could be replaced with a continuum cylindrical shell with a circumferential crack length of 0.83 nm. Furthermore, the damage variable is discussed to achieve a method for estimating the effective Young's modulus of defected nanotubes with numerous defects subjected to the progressive damage. This estimation method is evaluated by the atomistic based FE simulation of a double defected CNT.Materials and Energy Research CenterInternational Journal of Engineering1025-249528320150301A Numerical Analysis for the Effect of Slip Velocity and Stenosis Shape on Non-Newtonian Flow of Blood (TECHNICAL NOTE)44044672474ENAmit SinghMATHEMATICS, RBS COLLEGE AGRAhttps://orcid.org/0R.K. ShrivastavDepartment of Mathematics, Agra College AgraAmit BhatnagarDepartment of Applied Sciences (Mathematics), Faculty of Engg and Tech, Agra College AgraJournal Article19700101The aim of this paper is to study the effect of slip velocity and shape of stenosis on non-Newtonian flow of blood through a stenosed arterial segment. Blood is modeled as Bingham-Plastic fluid in a uniform circular tube with a radially non-symmetric stenosis. The problem is investigated by a joint effort of analytical and numerical techniques. The influence of stenosis shape parameter, slip velocity, stenosis height and yield stress on blood flow through a stenosed artery has been examined. The variations of wall shear stress, resistance to flow, volumetric flow rate and axial velocity with stenosis shape parameter, yield stress and slip velocity have been shown graphically. It is noticed that axial velocity and volumetric flow rate increase with slip but decrease with yield stress. This information of blood could be useful in the development of new diagnosis tools for many diseases.Materials and Energy Research CenterInternational Journal of Engineering1025-249528320150301Experimental Analysis of Effects of Ultrasonic Welding on Weld Strength of Polypropylene Composite Samples44745372475ENAliakbar GhaderiFaculty of Mechanical Eng., Shahid Rajaee Teacher Training UniversityNasrollah Bani Mostafa ArabMechanical Engineering, Shahid Rajaee Teacher Training UniversityMohammad Morad SheikhiMechanical Engineering, Shahid Rajaee Teacher Training UniversityReza NikoiFaculty of Mechanical Eng, Shahid Rajaee Teacher Training UniversityAbas Arham NmaziMechanical Engineering, Shahid Rajaee Teacher Training UniversityJournal Article19700101In the present study, method of ultrasonic welding of plastics is used to join the overlap of Polypropylene composites reinforced with glass fiber. The effects of process parameters, including time, pressure, vibration amplitude and amount of glass in composite on strength of welds. To reduce the number of tests and cost, the effect of changing parameters on strength was examined through Box-Behnken test by considering four factors at three levels and parameters were optimized to obtain the highest level of strength. The results of present study showed that maximum failure force is about 2.30 KN, and it is observed when air pressure is 1.5 times more, and amplitude is close to more than 32 micron (more than average), length of welding is 0.4 second and amount of glass used is about 10 percent.Materials and Energy Research CenterInternational Journal of Engineering1025-249528320150301Effect of Heat Recirculation in Biomass Flame Stability within a Cylindrical Micro-Combustor (TECHNICAL NOTE)45445972476ENMohammad Javad NorooziFactuly of Engineering, Ayatollah Borujerdi University0000-0003-3448-7518Journal Article19700101Flame stability inside a cylindrical micro-combustor was studied. Considering occurrence of heat recirculation, the respective relations were written and with parameters such as motion speed of reactants, flame propagation speed and thermal conductivity of the combustor’s wall, flame stability and its location inside micro-combustor were studied. It was found that for each thermal conductivity of the combustor’s wall, there is only one point inside the micro-combustor that if flame is formed in that point, it will be able to remain stable inside micro-combustor. It was also found that for each thermal conductivity of the combustor’s wall, flame inside the combustor remains stable only in one specified range of motion speed of reactants. In addition, blow-off limits were obtained for high and low speeds of reactants inside the combustor for different values of thermal conductivity of the combustor’s wall.Materials and Energy Research CenterInternational Journal of Engineering1025-249528320150301Study of Degradation of Dry Cooling Tower Performance under Wind Conditions and Method for Tower Efficiency Enhancement (RESEARCH NOTE)46046672477ENM.A. ArdekaniMechanical Engineering, Iranian Research Organization for Science & TechnoMohsen Mazidi SharfabadiMechanical Engineering, Islamic azad University, Bafgh BranchF. FarhaniMechainical Engineering, Iranian Research Organization for Science & TechnoJournal Article19700101Wind affects adversely the cooling tower thermal performance. A field investigation was carried out to study the thermal performance of Heller cooling towers under wind conditions, involving measurement of wind velocity and its direction around the cooling tower, and obtaining water flow rates and temperatures at the cooling tower inlet and outlet. Results show that air suction at the tower top prevents flow separation at tower periphery. Additionally, due to better airflow distribution over the front cooling sectors, perpendicular to wind direction, the thermal efficiency is improved compared to the sectors on the tower periphery, parallel to wind direction, resulting in about 20% more heat transfer. Moreover, the thermal performance of the front sectors improves with increase in the wind velocity, while it decreases with increase in the wind velocity for the periphery sectors and those at the back of the tower.Materials and Energy Research CenterInternational Journal of Engineering1025-249528320150301Effect of Deflected Membrane Electrode Assembly on Species Distribution in PEMFC46747572478ENIraj Mirzaeemechanical engineering, urmia universityFarzin RaminMechanic, TabrizMorteza Khalilianmechanic, universityS. Mehdi Pesteeimechanic, universityAshkan Torkavannejadmechanic, universityJournal Article19700101This article presents the results of a numerical study, using computational fluid dynamics (CFD) analysis to investigate the species distribution of proton exchange membrane fuel cells (PEMFCs) with deflected membrane electrode assembly (MEA). These new geometry were examined while employing three-dimensional, single phase, non-isothermal and parallel flow for model of a PEM fuel cell. This numerical research has concentrated on the effect of new kind of deflected MEA while maintaining the same inlet and boundary condition. Initially the CFD result of polarization curve has been validated with the available experimental data and shown good concord then studied deflected and flatted MEA at cathode and anode side. Investigation showed better results for the PEMFC with having both flatted and deflected MEA at cathode side than base model because of having more reacting area, uniform distribution of reactants, better oxygen transportation to the GDL at shoulder region and having less Cathode Overpotential (COP) which is the main causes of losses. Materials and Energy Research CenterInternational Journal of Engineering1025-249528320150301Investigation of Thermo-hydraulic Performance of Circular Tube Fitted with Center-cleared Twisted Tape Using CFD Modeling (RESEARCH NOTE)47648272479ENMojtaba Aghajani DelavarMechanic Engineering Dept, Babol Noshirvani University of TechnologyYousef VazifeshenasMechanical Engineering, Babol University of TechnologyJournal Article19700101The article presents a practical technique for enhancing thermo-hydraulic performance of a circular tube. In this way, numerical method focusing on laminar tubular flow is used to compare the effectiveness of utilizing center-cleared twisted tapes instead of typical shape of short width tapes. Numerical analysis represented that using both center-cleared and typical shape of twisted tapes, Re enhancement reduces the flow resistance. Studying short width twisted tapes showed that decreasing the width of twisted tape, reduces the heat transfer and hydraulic performance. Contrarily, using sufficient clearance for center-cleared twisted tapes can increase the heat transfer. Hence, applying center-cleared twisted tape as a tool of enhancing heat transfer can be a promising and practical idea.Materials and Energy Research CenterInternational Journal of Engineering1025-249528320150301The Research on the Biggest Borehole Curvature that Allowed through for the Rotating Casing (RESEARCH NOTE)48348972480ENHuimin YuanPetroleum Engineering Institute, China University of Petroleum (east China)Chunhao WanPetroleum Engineering Institute, China University of Petroleum (east China)Liu YilingPetroleum Engineering Institute, China University of Petroleum (east China)Yuhuan BuPetroleum Engineering Institute, China University of Petroleum (east China)Longlong GePetroleum Engineering Institute, China University of Petroleum (east China)Journal Article19700101With the development of highly-deviated well cementing techniques, rotating casing cementing technology has got more and more attention. The rotating casing technique can improve the displacement efficiency of cement paste, and then enhance the quality of well cementation. In the stuck section, the rotating casing can redress the well to make the casing run sequentially. The casing endures shear stress in rotating, besides axial stress, bending stress, circumferential stress and radial stress are produced by inside and outside casing pressure stress. These forces make it more complicated when calculate the maximum curvature in rotating condition than that without rotation. The paper, by analyzing the casing stresses in rotating condition, assumes a stress model of the casing infinitesimal for rotating casing, puts forward the calculation method for the maximum allowable borehole curvature in casing bucking deformation, or when casing couplings and thread seal fail under rotating condition and determines the biggest borehole curvature that allowed though, laying a base for the design and construction of the highly-deviated well casing.