---

The effective design of structures resistant to seismic vibrations is one of the main concerns of structural engineers to deal with damages caused by earthquakes, which can withstand more earthquake forces with methods such as energy dissipation. Recent earthquake records show that the earthquake record characteristic of the near area differs from the earthquake records of the far area. Among these characteristics, it can be mentioned that the pulse-type state of these records, as well as the high maximum speed and ground displacements. For this reason, these types of records increase the seismic requirements of the structure compared to normal earthquakes. The map of faults and seismic zoning of Iran shows that important urban points such as Tehran, Tabriz, etc. have high seismicity and are located near the fault. Therefore, it is necessary to design and build structures that can properly withstand the features of near-fault earthquakes, this issue reveals the understanding and recognition of the behavior of structural systems and the structure's response to the special features of near-fault earthquakes. This article first investigated the seismic evaluation of three existing 4, 8, and 12-story steel structures with lateral load-resisting systems. Then the desired structure was strengthened using a friction damper, and finally, the acceleration recorder was applied to the structure in the near- and far-fault earthquake zone case study. The seismic demand of the retrofitted structure was investigated in ANSYS Workbench finite element software, which was done in the form of modal analysis, floor drift displacement, structure acceleration response, and von Mises stress. For seismic validation, a two-story, single-span steel frame has been used. The dynamic load used was 0.5g based on the north-south component of the El Centro earthquake (1940) with a maximum acceleration scaled to 50 cm/s. To validate the numerical results, the horizontal displacement of two points on the first and second floor was compared with experimental data, and an acceptable accuracy was obtained. The results of the maximum acceleration at the highest point of the building showed that in a far-fault earthquake zone, the best effect of dampers was on 8-story buildings with a 77% decrease, and in a near-fault earthquake zone, it was related to a 4-story building with a 66.4% decrease in acceleration. Stress in near- and far-fault earthquake zones, the best effect of dampers was on 4-story buildings with 83% and 84% reduction, respectively. In a far-fault earthquake zone, the best effect of dampers was on 8-story buildings with a 44% reduction in maximum displacement, and in a near-fault earthquake zone, it was related to a 4-story building with a 61% reduction in acceleration.
 

---

Low Intensity Magnetic Separators (LIMS) are widely used in research and industry. The design of this separator is based on drum rotation inside a tank media, so that a permanent magnets placing inside the drum as an angle form, produces a magnetic field. In this study, the behavior of magnetic and none-magnetic particles of a pulp, flowing through a magnetic field in the wet LIMS, was simulated and validated by experimental results. The magnetic field variables were calculated in an FEM based simulator (COMSOL Multiphysics); while particles’ tracking was done applying CFD numerical method, enhanced by discrete phase model (DPM). The difference between the results of the simulation and the magnetic separation experimental test (recovery of magnetic particles in the concentrate product) was 16.4%. In order to quantify the results of the simulation, magnetic separation simulation was performed by changing two variables affecting the magnetic separation process (variables of particle size of the input pulp feed particles and solid percentage of input pulp) and corresponding experiments. Comparison of laboratory and simulation results showed that the trend of simulation results is consistent with laboratory results of the weight recovery (in both variables under study), so that the maximum simulation error is related to the size of 125 microns (16.5 %) and the lowest simulation error was in 180 microns (11.4 %). Also, the lowest simulation error in the weight recovery prediction was related to the pulp feed solid percentage of 15% (equivalent to 14%) and the highest simulation error was in 30% pulp feed solid percentage (16.9 %). This proposes that FEM-DPM-CFD coupling model, can be applied for simulation, optimization, design and construct 

---

In this research behavior of bubble due to under water explosion and it’s effects on ship structure have been studied. For determination of these effects field equations must be derived and solved them by mathematical simulation. Mathematical model is com in follow, it show physical rules on impression of bubble oscillation on body ship. This model is solved by combination of Euler method, 5 step Adams-Beshforse method and 4 step Adams-Moltone method for explaining the response of ship structure due to oscillation bubble. In order to agreement of solution way, stress-strain curves that obtained in this paper, is compared with experimental results. Also this results compared with FEMA results. Ship structure is modeled in ANSYS software in free beam form with variable mass and stiffness elements. Internal ship’s equipments and buoyancy are modeled by local mass and spring. The effect of explosion depth and explosive mass on stress in ship structure is studied. These result show when explosion depth is increased, stress is decreased and when explosive mass is increased, stress is increased.

---

In this paper comparison of finite element results and experimental observations of the hydroforming deep drawing is considered in which fluid pressure is used instead of die. Effects of hydroforming parameters during the process are studied, and a comparison with conventional method in deep drawing of aluminum alloys sheets with different blank diameters is presented. Large strain effects, anisotropic material properties, and the Coulomb friction theory in contact surfaces have been considered. ABAQUS code was used for simulation of process. In the first step, the numerical results have been verified by available experimental results, which showed a good agreement. These results contain force-punch travel and thickness strain. In the next step, the effects of initial pressure, friction, and punch radius on wrinkling, tearing, earring, and thickness strain have been studied. The results showed the range of pressure container for the hydroforming deep drawing. A comparison between some of the common deep drawing methods has been presented based on two main failure criteria and thickness strain criteria. Finally it is concluded that the hydroforming process is a more efficient method for achieving the higher drawing rate with respect to the conventional methods.

---

In this paper comparison of finite element results and experimental observations of the hydroforming deep drawing is considered in which fluid pressure is used instead of die. Effects of hydroforming parameters during the process are studied, and a comparison with conventional method in deep drawing of aluminum alloys sheets with different blank diameters is presented. Large strain effects, anisotropic material properties, and the Coulomb friction theory in contact surfaces have been considered. ABAQUS code was used for simulation of process. In the first step, the numerical results have been verified by available experimental results, which showed a good agreement. These results contain force-punch travel and thickness strain. In the next step, the effects of initial pressure, friction, and punch radius on wrinkling, tearing, earring, and thickness strain have been studied. The results showed the range of pressure container for the hydroforming deep drawing. A comparison between some of the common deep drawing methods has been presented based on two main failure criteria and thickness strain criteria. Finally it is concluded that the hydroforming process is a more efficient method for achieving the higher drawing rate with respect to the conventional methods.

---

A non-linear finite element model could be a useful tool in the development of a method of predicting soil pressure-sinkage behaviour, and can be used to investigate and analyze soil compaction. This study was undertaken to emphasize that the finite element method (FEM) is a proper technique to model soil pressure-sinkage behaviour. For this purpose, the finite element method was used to model soil pressure-sinkage behaviour and a two-dimensional finite element program was developed to perform the required numerical calculations. This program was written in FORTRAN. The soil material was considered as an elastoplastic material and the Mohr-Coulomb elastoplastic material model was adopted with the flow rule of associated plasticity. In order to deal with material non-linearity, incremental method was adopted to gradually load the soil and a total Lagran-gian formulation was used to allow for the geometric non-linear behaviour in this study. The FEM model was verified against previously developed models for one circular footing problem and one strip footing problem and the finite element program was used to pre-dict the pressure-sinkage behaviour of the footing surfaces. Statistical analysis of the veri-fication confirmed the validity of the finite element model and demonstrated the potential use of the FEM in predicting soil pressure-sinkage behaviour. However, experimental verification of the model is necessary before the method can be recommended for exten-sive use.

---

Fine-blanking is an effective and economical shearing process which offers a precise and clean cutting edge finish, eliminates unnecessary secondary operations and increases quality. Fine-blanking process utilizes triple-action tools: a punch, a stripper with an indented V-ring and a Counter punch (ejector) to generate a highly compressive stress state. The deformation is more violent and localized than that of any other metal forming operations. Therefore it is difficult to fully understand the mechanism of the process. This study investigates the effect of V-ring indenter, clearance of die, Force of holder and Counter punch, etc on state of stress, quality and accuracy of production. Some parameters have both positive and negative effect on quality of production and the life of the tool. Utilizing V-Ring indenter in Die will increase quality of production and life of the tool. Also Artificial Neural Networks was used to simulate Fine-Blanking process. It has been shown that booth of FEM and ANN is suitable for simulating and forecast of effect of the parameters on production.

---

Tubular components, such as stepped tubes, conical tubes and box-shape tubes, are mainly produced by tube hydroforming process. Obtaining a sharp corner is the main goal in some of these components. In this paper, corner filling in stepped tubes is studied using a new multistage hydroforming die. The proposed die was simulated and filling of the die cavity was investigated. The finite element software, ABAQUS 6.4, has been used for simulation. In order to verify the simulation results, the new die of stepped tube was manufactured and then experiments have been performed on it. The results of the experiments verified the simulation results. It was shown that by using the new die, parts with sharp corners could be produced. The simplicity of the die and the low internal pressure are among the advantages of this die.Thickness distribution was also examined by FE simulation and via experiments and it is shown that a better distribution could be obtained by the proposed die set.

---

Condition monitoring of BLDC motors due to their important applications is gaining more and more significance. Rotor eccentricity is one of the most important sources of faults in these motors. Up to now, detection methods of this fault under nonstationary conditions are limited to complicated and time-consuming methods using wavelets and Cohen class algorithms which are difficult to implement and need heavy computations to run. In this paper a novel method based on the modified Motor Current Signature Analysis method is proposed to detect the rotor eccentricity fault of BLDC motor operating under varying speed conditions. Stator current of healthy and faulty motor which are modeled by the Finite Element Method are simulated. By changing the representation of stator current from time basis to angle basis, the current signal will become stationary. Thus there is no need for methods using time-frequency analysis. Afterwards the Order Analysis Method is applied to the simulated healthy and faulty angle-based current signal and the results are compared with each other. Finally, the fault is detected by this comparison.

---

Residual stress measurement is one of the most interesting research areas in experimental mechanics. Residual stress is introduced to material due to plastic deformation of parts and can be one of the most effective parameters on design and operation of parts. ASTM E837-01 standard studies residual stress determination in parts by hole drilling method and represent calibration coefficients for flat sheets with constant stress profile. However, there is no certain standard on the residual stress measurement by Incremental Hole Drilling Method (IHDM) which is the subject of this study. IHDM can obtain stress profile by using two modified stress calibration coefficients. In this article, the stress calibration coefficients have been extracted for incremental hole drilling by using finite element analysis (FEA). FEA contains both biaxial tension test and pure shear test which a hole has been drilled step by step in the parts by removing elements and the strains changes were determined at three strain gauge positions on the surface. At last, the calibration coefficients are determined for each step and the accuracy of coefficients have been verified by a set of experimental test and a FE analysis. The experimental test contains four-point bending of an AA5056 flat aluminum sheet. The numerical analysis contains four-point bending of a flat sheet. In both cases, the stress profile can be determined easily by using analytical equations. Average analytical stress in each increment has been calculated and compared with the result of numerical incremental hole drilling method. The comparisons show that numerical and experimental results have no significant differences in first six steps but in the last four steps show an increasing errors due to the change in stress profile and hole geometry. Results presents that the calibration coefficients have suitable accuracy in stress profile determination.

---

In this paper torque ripple in switched reluctance motor is studied. The presented method in this paper for minimization of torque ripple is based on suitable machine structure obtained from the genetic algorithm (GA) and suitable machine driver. In the presented paper, the parameters of one machine are chosen as the reference machine parameters. Then some parameters of machine are chosen, which have no effects on the characteristics of mechanical, power and volume of reference machine. The desirable machine is simulated by finite element software, and then the torque characteristics are obtained for different machine structure with various machine parameters. Finally, with GA the best parameters for the design of machine with minimum torque ripple are chosen. So this paper presented for the first time an accurate method by finite element method in the process of machine design by GA. The finite element method used in the previously studies in the design of machine only for machine analysis, but in this paper finite element method is used in the process of machine design. So this method of machine design can be replaced to a conventional method. In this paper, the design of SRM driver is presented based on the best machine structure which is chosen from GA. So, the profile of machine torque for this structure has minimum deviation from the ideal torque without the ripple

---

Drying is an important operational step in pistachio processing. There is a decrease in moisture content of pistachio nuts from 56-57% (d.b.) to 5-6% during the drying process. Drying conditions affect the quality of dried pistachio nuts, therefore, this calls for an accurate description of the drying trend in the process. In this study finite element formulation and solution of diffusive moisture transfer equation was presented to improve the drying simulation of nut as an axisymmetric body. The Fick’s diffusive model was solved with effective moisture diffusivity of 5.24×10-10 m2 s-1 for 55C and 7.01×10-10 m2 s-1 for 70C. For experimentation, thin layers of pistachio nut, ‘Ohadi’ variety, were dried at high drying air temperatures (55 and 70°C), three replications for each treatment, along with drying air velocity and relative humidity of 0.5 m s-1 and 20%, respectively. Good agreement was observed when the output of model was compared with the experimental data. Mean Relative Deviation (MRD) calculated for the model and the experimental data for the air temperatures 55 and 70C, were found to be 6.2% and 8.1%, respectively.

---

Steel shear walls has been noticed against wind and earthquake lateral loads about high buildings in the last three decades. This modern phenomenon is growing rapidly worldwide so that system have been employed highly in construction of new buildings and seismic upgrading of existing buildings in some countries such as USA and JAPAN. That is a very simple system from viewpoint of implementing and there isn’t particular complexity. High strength and ductility are main advantages of these systems. Current paper has investigated comparatively behavior of steel shear walls made of smooth and corrugated sheets. Also the paper has assessed push-over curves and cyclic binding. According to this result of the research, corrugated steel shear walls have lower ductility than smooth shear walls. The research also founded that despite the high strength of corrugated sheets in low displacement, behavior of flat shear walls is more stable than corrugated shear walls. On the other hand flat steel shear walls attract energy more than corrugated shear walls. Therefore using of flat shear walls is recommended in high seismic regions. In this research, 18 samples of flat steel shear walls and corrugated shear walls were modulated. In all models, panels height were 3 m and panels span were 3, 4 and 5 m. the thickness of sheets in the samples were 3, 4 and 5mm. According to results of the research: 1- Corrugated sheets are unstable and unpredictable in high thinness. In the low displacements occurs a mutation state, so it distinguishes the corrugated and flat shear walls behavior. 2- At low displacement, a corrugated sheet bears greater load than a flat sheet. 3- In a constant thickness for thinner corrugated sheets is increased the mutation rate and its behavior becomes more non-uniform. 4- Despite of the fact, pynchyng phenomenon appears in all samples, but all samples behavior is stable and significant energy attraction is observed.

---

Abstract- This paper reports the finite element modeling of axial crack growth in a thin aluminum tube under gaseous detonation loading. The finite element method was used to handle the moving load and also the nonlinear characteristics of the problem. The simulation results were compared with the experimental results reported in the literature and also with the results obtained from an analytical model. Moreover, the cohesive element with traction-separation law was used for the crack growth modeling. The final part of the paper is devoted to comparisons between the numerical crack growth simulations obtained from the current work and the numerical results based on the CTOA criteria that were previously reported in the literature. The very good agreement between the two methods was indicative of the robustness of the implemented procedures. (this abstract seems a good description for this paper from the author point of view. please consider above text as abstract of this paper.)

---

The design of the structural supports has always been practically important in engineering applications. In addition to holding a structure properly, supports can also be utilized to improve the structural performances. In this study, by using modified finite element method (MFEM) and Imperialist Competitive Algorithm (ICA), the maximum of bending moment was minimized. In this paper both elastic and rigid supports are taken into account. As compared to other design optimization methods, ICA is robust, more efficient, and requiring fewer number of function evaluations, while leading to better quality of results. Appling the modified finite element method not only reduces computational cost and increases convergence rate, but also reach the global optimum position of supports. Three classical examples are given to demonstrate the validity and capability of the proposed optimization procedure for finding the global support positions. Results show that support position optimization by using present method, can reduce the maximal moment significantly, and deserves more investigation.

---

Since there are struggles with CNTs dispersion in the resin and production costs, synthesis and test of epoxy/carbon nanotube (CNT) nanocomposites is not economical. For this reason, simulation methods are proper techniques to predict mechanical properties of these nanocomposites. But the actual dimensions of CNTs and their length to diameter (aspect) ratio is a cause for concern in nano and micro scale finite element modeling. In this paper, different arrangements of CNTs in epoxy matrix have been presented using a beam element as a CNT and creating representative volume element of nanocomposite in micro scale. Effects of volume fraction, aspect ratio and wave effects of CNTs on nanocmposite effective elastic moduli have been investigated. The results show that this method eliminates the limitation of both micro and nano molding and simulates the real conditions of nanocomposites and can be used to examine the effects of geometric parameters in the effective moduli. On the other hand, the simulation results have a good agreement with experimental results.

---

In the present work, creep buckling of linear viscoelastic plate was studied. Pseudo-transient or Dynamic Relaxation method with finite element discritization was used for solving the nonlinear governing equations of the plate. The displacements were based on first order shear deformation theory. Von Karman assumptions were considered for strains, including initial imperfection of the plate. Central deflections of the rectangular PMMA plate as well as end-shortenings were obtained during the loading of the plates with simply supported and clamped edges. The results compared well with commercial finite element code ANSYS.

---

In this paper, the eXtended Finite Element Method is implemented to model the effect of the mechanical and thermal shocks on a cracked 2D orthotropic media. The uncoupled thermoelasticity equations are considered. Isoparametric four-node and eight-node rectangular elements are used to discrete governing equations. The dynamical stress intensity factors are computed by the interaction integral method. The Newmark and the Crank–Nicolson time integration schemes are used to numerical solve the spatial-discretized elastodynamic and thermal equations, respectively. A MATLAB code is developed to carry out all stages of the calculations from mesh generation to post-processing. Several elastic and thermoelastic numerical examples are implemented, to check the accuracy of the results and to investigate the effect of the orthotropic direction on the stress intensity factors.

---

In this study, an analytical solution is presented to calculate interlaminar stresses in long symmetric cross-ply composite laminates subjected to uniform axial strain and thermal loading. At first, the most general form of layerwise-based displacement field is extracted by a successive integration of elastic strain–displacement relations and imposing the physical restrictions based on deformation patterns of these laminates. The equilibrium equations are then derived by using the principle of minimum total potential energy and solved analytically in order to obtain three-dimensional stress field in the laminated plate. Finally, various numerical examples are investigated in order to validate the efficiency and accuracy of the layerwise theory in predicting the interlaminar stresses. For the assessment of the accuracy of the proposed method, the interlaminar stresses are also calculated within the framework of a 3D finite element analysis using the Abaqus software. The corresponding numerical results are in good agreement with those obtained through the layerwise theory. All results indicate that the presented approaches have a good prediction capability of interlaminar stresses in interior regions of the laminate and theirs high stress concentration near its free edges that can cause delamination failure.

---

The Incremental Sheet Metal Forming (ISMF) process is a new and flexible method that is well suited for small batch production or prototyping. In this study, after the process simulation with ABAQUS software and verification of results through experimental tests, the effects of three parameters including friction coefficient, tool diameter and vertical step size on three objectives including vertical force, minimum thickness of deformed sheet and amount of spring-back are investigated. A neural-network model is developed based on simulation data and the effects of parameters are studied on each objective. Also multi-objective genetic algorithm is performed to get the Pareto front of optimum points.