Mahmoud Salimi

• PhD
• Professor (Full) at Isfahan University of Technology

Sand control screens are necessary for steam-assisted gravity drainage (SAGD) wells drilled into oil sands to prevent sand production. However, the accumulation of mobilized fine particles near the wellbore can result in screen plugging, adversely affecting the well’s flow performance. This research assesses the effects of formation water salinity...

This paper assessed and ranked several alternatives to control sand production in a well recompletion effort of offshore gas wells that have experienced massive sanding. The aim was to select an appropriate thru‐liner sand control system to increase well productivity. Four different screen types were evaluated, including a wire‐wrapped screen (WWS)...

Granular flow is a scientific problem with applications in many engineering problems such as sinkholes, ground surface collapse, and soil loss into a defective pipe. In most previous studies, however, only single size grain has been considered in mass flow rate calculations for simplicity. In nature, most granular materials have different sizes of...

The sand retention and the retained permeability or flow performance of sand control screens in unconsolidated formations are usually evaluated through the pre-packed sand retention testing (SRT) procedures. These procedures attempt to address a complex process of fines migration which influences the flow performance of screens in formations with r...

Erosion has been recognized as one of the major threats for industries involving multiphase transportation pipelines. Within the last decades, effective parameters on wear pattern have been identified. As a result, the (famous) V-shaped erosion profile has been detected for the pipes' elbow section. In this study, CFD is employed to investigate the...

Slotted liners have been widely used in steam-assisted gravity drainage (SAGD) wells owing to their low cost and superior mechanical integrity. Multiple factors affect the performance of slotted liners, such as particle size distribution (PSD) of formation sands, aperture size, slot density, fluid flow rate, and wellbore operational conditions. Cur...

In this paper, micromechanical simulations are employed to evaluate the performance of the Tsai–Wu and Hashin failure criteria for fiber-reinforced composites, especially in stress states whose experimental reproduction is complicated. Micromechanical responses are generated using a finite element model of a representative volume element, in which...

Profile and shape control is utilized to maintain the dimensional quality of a rolled strip. Prediction of work roll thermal expansion is an important element in controlling the strip profile and flatness in a modern, high-speed rolling mill. In this study, a full three-dimensional analytical model “based on the finite difference method under trans...

When two bodies slide on each other, friction is created. By superposing ultrasonic oscillation to one of the bodies, the friction force is reduced .This phenomenon is widely used in metal forming and metal cutting. For the production and transmission of ultrasonic vibrations to a target it is required to use an ultrasonic system the components of...

The formability of the clad metal sheets is influenced by many factors such as mechanical properties of the component metals, so that producing clad cups with high formability free of defects is not easily possible. The behavior of clad sheet, vis-à-vis single-layer sheets, is comprehensively studied through experimental as well as numerical method...

In this study, an artificial neural network model is proposed to predict the flow stress variations during the hot rolling process. Optimization of the proposed neural network with respect to number of neurons within the hidden layer, different training methods and transfer functions of the neural network is performed. The results of the optimal ne...

In this paper, a new theory is introduced to explain chatter mechanism based on wave propagation in elastic solids. It is believed that previous theories in chatter are based on a static analysis and normally are consistent just for low-frequency vibrations such as forced vibration. But chatter phenomenon is a dynamic high-frequency event and requi...

In this paper, the chattering phenomenon in cold rolling is investigated in reference to the finite element method (FEM). The structure of the mill stand is modeled as a system of linear springs and lumped masses while the rolling process is modeled utilizing an implicit FEM. Assembling the two models makes it possible to detect the chatter during...

Many experimental observations have shown that in most nanostructures such as nanocomposites, carbon nanotubes (CNTs) are often characterized by a certain degree of waviness along their axial dimension. This geometrical imperfection has a profound effect on the mechanical behavior of CNTs. In the present work, the effects of initial curvature, shea...

This work is an attempt towards employing ductile damage criterion and finite element simulations for prediction of fracture initiation and evolution in deep drawing of copper/stainless steel clad sheets. The material mechanical properties and ductile damage parameters were determined through standard and notched tensile tests. The effect of some i...

When two bodies slide on each other the asperities are engaged and deformed which causes the dynamic friction. By superposing ‎ultrasonic oscillation to one of the bodies, the friction force is reduced . The experiments show that the friction force may be reduced by ‎about 60 percent depending on material properties and the kinetics of the two bodi...

In this paper, an inverse analysis technique is used to obtain the flow curve of materials in a hot rolling finishing mill. This technique is based on minimization of the differences between the experimental and computed values. The flow curves and the friction coefficients at roll/work-piece interface are derived from two different models. Model I...

A theoretical model based on slab method is proposed to analyze asymmetrical rolling of bonded two-layer sheets where the ingoing sheet is forced to horizontally enter the roll gap. Separate equilibrium equations as well as yield relations are derived for each layer by considering different stress fields for the two layers of any slab within the ro...

In this study, an artificial neural network model is proposed to predict the flow stress variations during the hot rolling process. Optimization of the proposed neural network with respect to number of neurons within the hidden layer, different training methods and transfer functions of the neural network is performed. The results of the optimal ne...

In rolling of wide strip, longitudinal compressive stresses develop as a result of nonuniform deformation along the plate width, which enhance long-shape wave. Theoretical assessment of these stresses and factors affecting their magnitude and distributions are not emphasized in existing solutions, since most of the solutions are based on the assump...

A new multi-pass hot shape rolling was designed based on a three-dimensional analysis of channel section beams in hot rolling by the finite element method. A complete production line in industry containing 13 passes in forming the section including break-down, intermediate, and finishing sequences is modeled. The output geometry and power consumpti...

In this paper, the effects of inclusion waviness and its distribution to the effective carbon nanotubes (CNTs)/shape memory polymer (SMP) composites stiffness is investigated. A micro mechanical model is developed to take into account the waviness effect of nanotubes, which are assumed as solid short fibers with a circular cross-section and exhibit...

In this investigation, explosive welding and heat treatment processes provided an effective method for manufacturing high-strength and high-ductility copper/ austenitic stainless steel couple. In order to improve diffusion in the interface of copper/stainless steel, first the tensile samples were provided from the welded part, then they were subjec...

In rolling of wide strip, longitudinal compressive stresses develop as a result of non-uniform deformation along the plate width, which enhance long-shape wave. Different reduction as a result of uneven geometrical factor along the plate width considered as a main cause of such non-uniform deformation in flat rolling. In order to investigate the no...

In this paper, asymmetrical rolling of bonded two-layer clad sheets is studied using the slab method of analysis. It is assumed that the ingoing sheet is guided to horizontally enter the roll gap and that the work rolls may have different pressure distributions. Unlike the existing slab models, the slabs are not divided into two parts with differen...

This article focused on three-dimensional analyses of a functionally graded material plate which contains a semi-elliptical surface crack and subjected to transient thermal loading. Strain singularity around the crack front is simulated using collapsed 20 - node quarter - point brick elements. Three-dimensional displacement correlation technique is...

Chatter is the most important limitation in high speed rolling of thin strips in modern industrial cold rolling mills. To study chatter in rolling, it is necessary to set up models for the rolling process as well as the mill stand. Existing models of the rolling process are analytic and are based on many simplifying assumptions. In current work Arb...

Mechanical and thermal properties significantly affect many aspects of machining, such as chip formation, cutting forces, cutting temperatures, and surface integrity of machined products. One of the most important mechanical properties is the material flow stress, which is governed by the field variables including the strain, strain rate, and tempe...

A theoretical method based on slab method of analysis is presented to give an account to the developed curvature in asymmetrical sheet rolling where the work rolls radii, their speeds, and the interfacial frictions may be different. In this model the ingoing sheet is considered to be guided to enter the roll gap horizontally and the work rolls may...

In this article, the small-scale effect on buckling analysis of radially compressed nanorings is investigated. The effect of small length scale is taken into account using nonlocal elasticity theory. The principle of virtual displacement is implemented to circular nanorings to derive the governing differential equations which are solved analyticall...

Chatter in high speed tandem mills affects the quality of the product and the production rate of the rolling mill. It may also cause damage to mill components and strip rupture. To monitor chatter generation within the rolling mill, it is highly recommended to use online chatter detecting systems. This paper presents a set of guidelines to optimal...

In present study, spinning process of clad sheets composed of Copper and Stainless steel 304L is investigated experimentally. To achieve the Copper-Steel 304L clad sheet the explosive welding method is used. In order to smooth the surface of clad sheets, a cold roll forming process was carried out. The clad sheets were heat treated to improve the m...

Export Date: 18 October 2014

Enhancement of blood fibrinogen or factor VII increases cardiovascular diseases. Allium hirtifolium Boiss (Mosir) has been shown to have cardioprotective effect. This study, therefore, aimed to evaluate the effects of Allium hirtifolium Boiss on factor VII and fibrinogen blood levels. Its radical scavenging property was also measured. Twenty four N...

In this article, an analytic solution for ring rolling process based on the slab method theory is presented, in which the non-uniformity of the normal and shear stresses across the section of the deforming material throughout the plastic region is considered. The friction factor multiplied by the shear yield strength (τ=mk) is used to present frict...

This paper investigates the asymmetrical rolling process using the Modified Slab Method. Elastic-plastic and linear work hardening material was assumed. In solving the equilibrium equations, the difference in roll pressure distribution was assumed linear. Using this model rolling parameters such rolling force, torque and the developed curvature wer...

Finite element method is a commonly used method in the simulation of plate and shell deformation. Usually, researchers in this field establish elements based on displacements of nodes and gradients of displacements with respect to a reference configuration as nodal variables. Recently, a new formulation, absolute nodal coordinate formulation (ANCF)...

This paper appraises two major chip formation techniques in finite element (FE) simulation of machining. The first one considers chip formation as a wedge indentation process, while the second one considers chip separation due to ductile fracture. The first technique has been implemented in an Arbitrary Lagrangian–Eulerian (ALE) simulation of machi...

In this research, polishing flat surfaces has been done by using a completely new and innovative method. In this method, rotary magnetic tool that carry magnetic abrasive powders, is placed in a very strong thermal induction field, and magnetic rotary tool frequently change its direction from clockwise (CW) to counterclockwise (CCW) and CCW to CW....

In this research work, polishing inside, outside and over the cylindrical parts has been done by using a completely new and innovative method. The work-pieces have been placed on a two-axis Cartesian CNC Table for polishing operations. The Magnetic Rotary Head continuously changes its rotation direction from CW to CCW and CCW to CW and meanwhile th...

Chatter is one of the most encountered vibration problems in high-speed rolling of thin steel sheets in tandem mills. Due to its negative cause on product quality and maintenance costs, chatter is a technical and economical problem in rolling mills. To study chatter in rolling, it is necessary to set up models for the rolling process as well as the...

In this paper, a numerical simulation of stress development within the air plasma-sprayed thermal barrier coating system incorporating nonlinear behavior under compression for the top coat ceramic layer is presented. The nonlinear behavior as well as its evolution with sintering at high temperature is simulated using a microstructure based model. T...

Slab method analysis of asymmetrical sheet rolling is presented to evaluate the outgoing curvature especially when the horizontal entry condition is maintained. Considering large bite angle, and assuming linear normal stress and parabolic shear stress distributions through the thickness direction, equilibrium relations as well as yield criterion ar...

Modelling of the strip profile and flatness with improved efficiency and accuracy is a matter of interest in achieving high quality flat-rolled products. There exists a high degree of non-linearity between the strip shape characteristics and process parameters. In this work, an Artificial Neural Network (ANN) model is presented which considers elas...

Chatter is usually one of the most difficult tasks to overcome in a rolling mill. Chatter is often associated with high rolling speeds and high reductions, conditions that are generally desirable in order to increase mill productivity. This paper presents the combination of various methods to optimize the 5-stands rolling process parameters in orde...

A group of 3-D finite element simulations using ABAQUS/Explicit is performed to study the parameters affecting the spread of working material in shape rolling processes. The results are verified by other analytical researches and available experimental findings. In the next step, a sample caliber design process to achieve a certain cross section is...

Several leading commercial FEM codes offer a number of fracture options without giving any guidance to the users in determining the fracture parameters for different materials. A modification is implemented to Johnson and Cook’s calibration method to provide simultaneous consideration of both active failure mechanisms in actual domain of the field...

Plasma sprayed ceramics have nonlinear behavior under compression in small deformations due to partially closing of microcracks existing in the microstructures. Their tangent modulus increases up to a certain value with an increase in compressive stress and indicate a stiffer response. In this paper, the nonlinear behavior of such materials is mode...

In this study, a three-dimensional (3D) model of a yarn pullout test for plain woven fabrics is introduced. The main focus of the study is on the realization of a 3D fabric geometrical model, the incorporation of anisotropic material properties and the validation of yarn and fabric finite element meso-models using experimental results. The material...

This paper presents a three dimensional analysis for hot rolling of channel section beams by the finite element method using ABAQUS/Explicit. A complete production line containing 13 passes for forming the section including breakdown , intermediate and finishing sequences are modeled, and the exit section of each pass is imported as the entering ma...

In this paper, modeling of physical behavior of plain-woven fabrics under the condition of yarn pullout test is investigated. An analytical model called “the oscillation model” is represented to estimate the required force of yarn pullout test for the plain-woven fabrics. The main idea of this model is based on a combined approach of friction in in...

Pullout test is a conventional and suitable method to investigate the effects of yarn properties and the structural characteristics of weave on fabric mechanical behavior. Frictional specifications of the fabric yarns influence the fabric strength and efficiency and its ability to absorb energy. This paper is concerned with formulating an analytica...

This paper deals with the modeling of the physical behaviour of plain-woven fabricss under the condition of yarn pullout test, and the investigation on an analytical model which is called "Oscillation Model", represented to estimate the required pullout force of yarn pullout test for plain woven fabrics. The main idea of this model is based on a co...

In the present work, influential parameters affecting the work roll wear are investigated. Essential theories related to work roll wear predictions are explained. The wear profile prediction after a rolling program is related to the material tonnage rolled. The roll barrel was divided into a number of equal segments and for each segment, the passed...

A fully coupled Electro-Thermo-Mechanical model is proposed in which the governing equations are derived within a continuum mechanics framework. This 1-D model is able to take into account shape memory effect and the pseudoelasticity as well as changes in length affecting the dynamic response of SMA wires. Firstly, zero-stress condition of an SMA w...

In this paper, a three-dimensional microplane model based on the formulation with static constraint using the volumetric-deviatoric split for thin walled shape memory alloy torque tubes is presented. The model is capable of predicting the behavior of an SMA torque tube in term of recovery shear stress at a fixed shear strain while the tube undergoe...

In this paper the crushing behavior of thin-walled tubes under static and dynamic loading is investigated. First, a finite element (FE) model for empty thin-walled tube was constructed and validated by available experimental and numerical data. The comparison between the FE results and the existing numerical solutions as well as the available exper...

پدیده ارتعاشات خود تحریک در قفسه های نورد سرد که در کل به عنوان چتر1 شناخته می¬شود نه تنها اجزاء مکانیکی قفسه را تحت بار بیش از حد قرار می¬دهد، بلکه به علت عیوب ظاهری به جای گذاشته بر روی ورق و تغییر ضخامت در آن ضررهاي بسيار زيادي را نيز به كارخانه هاي توليد فولاد وارد مي¬نمايد. در این مقاله دو مدل ریاضی برای فرآیند نورد و سازه نورد ساخته شده و با...

A three-dimensional microplane constitutive model utilizing statically constrained formulation with volumetric—deviatoric split is presented for shape memory alloys (SMAs). Shear stress within each microplane is described by resultant shear component on the plane. One-dimensional stress—strain laws are used for normal and shear stresses on micropla...

Pullout test is a conventional and suitable method to investigate the effects of yarn properties and the structural characteristics of weave on fabric mechanical behaviour. Frictional specifications of the fabric yarns influence the fabric strength and efficiency and its ability to absorb energy. This paper is concerned with formulating an analytic...

This paper concerns with simulation of foam-filled double, triple tapered and frusta thin-walled tubes under oblique loading. The main aim of this study is to quantify the dynamic crush load and energy absorption response of empty and foam-filled tapered thin-walled rectangular tubes under oblique loading. A finite element model was constructed ini...

In cold rolling of foils the deformations of rolls in comparison to the reduction in thickness of the work piece is large and cannot be ignored. It is possible to evaluate this deformation by considering the rolls and the work piece as elastic elements of varying stiffness in the working zone and by using the Hertezian contact stresses. Lubricants...

Tension levelling is a process used in steel industry in order to remove any shape defects present in temper rolled strip. Although strip undesired shapes come into sight as edge waves, centre buckles and quarter buckles may be corrected giving the strip a suitable amount of elongation in work rolls cassette, such defects of so-called crossbow and...

English Version is available under the conference proceeding.

Chatter is a particular case of self-excited vibrations which arise in rolling operations as a consequence of interactions between the structural dynamics of the mill stand and the rolling process. Dynamic forces generated in the rolling process deflect the structure of the mill, leading to variations at the roll gap and the roll speed. In such a c...

Self-exciting vibration of mills with constant or rising amplitude is called chatter vibration. Chatter limits the rolling speed, degrades product quality, and sometimes damages the mill. In this paper, a new parameter, namely, System Equivalent Damping (SED) is defined to quantitatively determine the stand potential of chattering. SED values less...

Dynamic phenomena in rolling mills, generally known as chatter, not only overloads the mechanical components of the rolling mill structure but also give rise to variations in gauge or to shape defects in the rolled strip. A complete study on chatter analysis in cold rolling mills was carried out in the current work. It considers an innovative idea...

In this paper the newly introduced parameter in part I, i.e., System Equivalent Damping (SED) is employed to determine the optimum rolling condition of a three-stand mill. For any stand, SED presents a quantitative measure that shows mill tendency to chatter. The ultimate goal is to maximize the velocity of the rolling mill. The method presented he...

A three-dimensional (3D) constitutive model based on a statically constrained microplane theory with volumetric–deviatoric split is proposed for polycrystalline shape memory alloys (SMAs) under multiaxial loading paths. Microplane governing equations are 1D stress–strain relations for normal and shear stresses on each microplane, in which suitable...

Dynamic phenomena in rolling mills, generally known as chatter, not only overloaded the mechanical components of the rolling mill structure but also give rise to variations in gauge or to a shape defect in the rolled strip. In this paper, first, two mathematical models have been proposed to represent the rolling process and rolling structure. Secon...

A one-dimensional coupled thermomechanical model is presented for shape memory alloys (SMAs) under non quasi-static loading by defining a Helmholtz free-energy function consisting of strain energy, thermal energy, and the energy of phase transformation. The first law of thermodynamics is used to address the thermomechanical coupling due to the infl...

Slab analysis of asymmetrical sheet rolling is presented by considering non-uniform normal and shear stress profiles across the section of product. An important phenomenon considered in this paper is the deflection of plate at entry to the deformation zone and the amount of which is predicted by using a genetic algorithm (GA). In the utilized GA, t...

A cold rolling model based on asperity flattening and von Mises homogenous deformation for mixed regime is developed. The variations of the yield stress with strain and strain rate are considered in this model. Reynolds accurate “second order” equation was used to obtain the hydrodynamic pressure of the lubricant film. A more accurate relation for...

Asymmetric sheet rolling is simulated by using an elastic–plastic arbitrary Lagrangian–Eulerian (ALE) finite element method. The ALE finite element approach easily predicts the curvature development due to inequality in work roll/plate surface finish (interface friction) and speed mismatch. An isotropic work hardening material is assumed. Reasonabl...

In this paper the energy consumption related to the roll pass design is studied. Three different types of passes that are commonly used in early stages of many hot rolling products known as break-down sequences (square–oval–square, square–box–square and square–diamond–square) were investigated by the energy consumption criteria. The geometrical par...

Axisymmetrical forging simulation of ring rolling is a shortcut to this process by the FE analysis. The method has been proposed using the conventional Lagrangian formulation. In this paper this method is applied to simulate T-section rings using ALE formulation. It is shown by this method that axisymmetrical forging idea applying the ALE technique...

In this paper, a theoretical model based on slab method of analysis for plane strain asymmetrical rolling is presented. In this model the non-uniformity of the normal and shear stresses in deriving of the governing equations are considered. This model can predict the required external loading to the plate at entry to keep the plate horizontal. The...

In this paper asymmetric plane strain rolling is analyzed by using an elastic-plastic ALE finite element method. Results of the ALE finite element investigation of curvature development due to inequality in work rolls/plate surface finish (interface friction) and speed mismatch are presented. Reasonable agreements were found between the numerical m...

This paper investigates the performance of the “Thermal Spokes Method” in modeling the effect of the guide rolls on the ring rolling process. If the guide rolls are not included FE, simulation encounters problems such as tilting of the ring and process instability. Thermal spokes are introduced to withstand any unwanted moment of the resultant roll...

A new method (thermal spokes) has been proposed to simulate the guide roll effect in FE analysis of the ring rolling process. The method is simple to use with existing FE formulations, does not introduce further nonlinearities, and results in more stable and faster solution to ring rolling simulations. The method has been successfully employed in a...

In this paper a new numerical method is presented in which the slit beam model is employed and further developed to include the surface elastic deformation of rolls due to the rolling load/roll separating force in a four high mill. Mathematical analysis and finite element method in calculating surface coefficients were used. Then the surface coeffi...

In this paper the general case of asymmetrical plane strain rolling due to unequal roll diameter, unequal surface speed of the rolls and different contact friction is considered. An analytical model based on the slab method of analysis was used and further developed to obtain the characteristics of asymmetrical sheet rolling and to predict strip cu...

In this paper, a theoretical model for plane strain deformation based on a slip line field (SLF) solution is developed to provide the strain distribution across a section of a product in plane strain drawing. The results obtained from the SLF solutions were compared to those of the finite element method. From both solutions, it is shown that the sh...

An account is given of the development of a ring rolling process for the manufacture of V-sectioned rings from thin-walled plain cylinders. The rings were required in different diameters and sectional dimensions for a specific application, and in the absence of any design information an analysis of the forming process was made to provide guidance o...

Tension leveling is a process used in steel industry in order to remove any shape defects present in temper rolled strip. Although strip bad shapes come into sight as edge waves, centre buckles and quarter buckles can be corrected giving the strip a suitable amount of elongation in work rolls cassette, such defects of so-called crossbow and coil se...