Majid Ghoreishi | K.N.Toosi University of Technology (original) (raw)

Papers by Majid Ghoreishi

Research paper thumbnail of ‫بررسي‬ ‫ماشينکار‬ ‫کمپرسور‬ ‫پره‬ ‫ريشه‬ ‫ي‬ ‫موتور‬ ‫گاز‬ ‫توربين‬ ‫ي‬ ‫فر‬ ‫با‬ ‫آ‬ ‫الکتريک‬ ‫تخليه‬ ‫يند‬ ‫ي‬ ‫سيم‬ ‫ي‬ ‫قريشي‬ ‫مجيد‬ Investigation of Machining of Compressor Blade Root using Wire Electrical Discharge Process

Manufacturing of blades in air turbine motors according to complicated shape and critical working... more Manufacturing of blades in air turbine motors according to complicated shape and critical working conditions needs a high technology. The root of blade under applied forces should have high surface quality and dimensional accuracy in comparison with the other blade components. In this study, the surface quality due to different types of available wire-cut machines for machining of compressor blade root has been investigated. To this end some samples has been machined by different wire-cut machines. Afterwards the different components of surface integrity (such as surface roughness, surface topography, hardness, thickness of affected surface layers, microcrackes and pits, residual stresses) has been studied. Finally, the machining of the root of compressor blade with this process has been discussed and concluded.

Research paper thumbnail of Sensitivity analysis of material removal rate in dry electro-discharge machining process

Dry electro discharge machining is one of the newest machining processes on which studies are rem... more Dry electro discharge machining is one of the newest machining processes on which studies are remarkably expanding. Its advantages include being environment friendly, low process costs, simple tools and equipment, optimized machining parameters and cheap dielectric. Considering fast expansion of this machining process, its optimized performance is desirable. Considering the material removal rate and the addition of the gas pressure and electrode rotational speed comparing to the conventional spark machining makes the analysis of effective parameters on material removal rate necessary for improving the process performance. In this study, the effect of different parameters such as machining gap voltage, electro discharge current, pulse on-time, pulse on-time to pulse off time ratio, dielectric gas pressure and tool rotational speed on material removal rate were studied using Sobol statistical sensitivity analysis method. In comparison with the other methods, it possesses the advantage...

Research paper thumbnail of Experimental Modelling of Nd:YAG Laser Percussion Drilling Process of Ti6Al4V Alloy

Research paper thumbnail of Numerical Investigation and Enhancement of Flushing Performance in the Micro-Electro Discharge Machining by Considering the Hole Depth and Dielectric Fluid

flushing of machining gap is one of the most crucial issues in the micro-EDM that not only remove... more flushing of machining gap is one of the most crucial issues in the micro-EDM that not only removes debris from the machining gap, but it also increases the machining efficiency. Identification of dielectric flow pattern provides a good perspective for its user to enhance the flushing performance. In this paper, the effects of the hole depth and dielectric fluid parameters on the flushing in micro-EDM are studied on the flushing in micro-EDM. Three different levels of 5, 10 and 15 mm for depth are considered, while deionized water, kerosene, and EDM-30 oil are chosen as dielectrics. To find out the effect of these parameters on flushing, computational fluid dynamics (CFD) based on boundary volume method is applied to solve the fluid flow in the flushing gap. To verify the numerical simulation model, a comparison was conducted between the results obtained in this work and the experimental and numerical results of the available literatures. The maximum difference between the results of...

Research paper thumbnail of Modelling and optimisation of temperature and force behaviour in high-speed bone drilling

Biotechnology & Biotechnological Equipment

Bone drilling and implantation are important in orthopaedic surgery, dentistry and also fracture ... more Bone drilling and implantation are important in orthopaedic surgery, dentistry and also fracture treatment. In many cases, due to the rise in temperature during bone drilling (higher than 47 C) and low conductivity of bone, thermal necrosis occurs. There is also risk of drill fracture due to the excessive thrust force. Despite many studies on the effect of different parameters on bone drilling temperature and force, there is still no clarity about the influence of the tool rotational speed and feed rate on the temperature and force responses. The aim of this study was to test and optimise the conditions in high-speed bone drilling, process force and temperature simultaneously. The results demonstrated that high-speed drilling is a suitable method for decreasing process temperature and force, and the rotational speed, feed rate and tool diameter were the most important factors in the high-speed bone drilling processes. Using a statistical method to model and optimise the process, a second-order model was developed to predict the behaviour of process temperature and thrust force in high-speed drilling. The optimised values were a rotational speed of 11778 rpm, feed rate of 50 mm/min and tool diameter of 2 mm, where the process force and temperature were 15.85 N and 33.4 C, respectively. Therefore, in high-speed bone drilling, the process thrust force and temperature decline, and the low effect of feed rate on temperature enables an increase in the speed of operation in robotic surgery.

Research paper thumbnail of Optimum design of vibratory electrode in micro-EDM process

The International Journal of Advanced Manufacturing Technology

Micro-electro discharge machining (EDM) has a crucial role in fabrication of parts such as molds.... more Micro-electro discharge machining (EDM) has a crucial role in fabrication of parts such as molds. One of the most challenging aspects of EDM process relates to flushing of debris. Increasing the material removal rate causes significant enhancement in EDM process. In this study, new numerical approach for enhancing flushing is proposed. A model of vibratory electrode and dielectric flow pattern is validated with theoretical and experimental results. Next, the effect of vibratory electrode geometry and its material properties on flushing of debris is investigated. To this end, design of experiment method is applied to find optimum vibratory electrode shape and material. At first step, vibrational analysis is performed for electrodes to find mode shapes and their corresponding frequency utilizing the finite element method. Vibrational results have good agreement with theoretical ones that are presented in literatures. Next, frequency response function analysis is done for vertical excitation force to find out displacements of electrodes in longitudinal modes. The results of these simulations are utilized to construct 3D computational fluid dynamic (CFD) models to find velocity distribution on gap space between electrode and work piece. Full factorial design is used to evaluate electrode’s parameters. The results from these simulations are studied to achieve best electrode shape that is able to flush the gap flow significantly. Finally, dielectric flow regime for optimum electrode shape is surveyed.

Research paper thumbnail of Sensitivity analysis of temperature and force in robotic bone drilling process using Sobol statistical method

Biotechnology & Biotechnological Equipment

The bone drilling process is indispensable in orthopaedic surgeries and treating bone breakages. ... more The bone drilling process is indispensable in orthopaedic surgeries and treating bone breakages. It is also very important in dentistry and bone sampling operations. Bone is a very complex material and the process of drilling is very sensitive. Thus, bone drilling is one of the most important, common in the field of biomedical engineering. The bone drilling process can be promoted using automatic drilling machines and surgery-assisting robots. The problematic issue during operation is the high increase in drilling process temperature (higher than 47 C) which leads to the so-called 'thermal necrosis' or cell death, and local burn in bone tissue. Furthermore, imposing higher forces to bone might yield to breaking or cracking, and consequently causes serious damages in bone. In this paper, the tool rotational speed, feed ratio and tool diameter were taken into account as process input parameters, and process temperature and thrust force were taken as output parameters. Design of experiments using response surface methodology was followed. Then, second linear governing equation was assigned to the model and its accuracy was evaluated. Later, Sobol statistical sensitivity analysis was used to ascertain the effect of process input parameters on process temperature and force. The results showed that among all effective input parameters, the tool rotational speed, feed rate and tool diameter have the highest influence respectively on process temperature and force. The behaviour of each output parameter with variation in each input parameter was further investigated.

Research paper thumbnail of Analytical and experimental study of effective parameters on process temperature during cortical bone drilling

Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine

Bone drilling process is a prominent step of internal fixation in orthopedic surgeries. Process f... more Bone drilling process is a prominent step of internal fixation in orthopedic surgeries. Process forces, leading to chip production, produce heat in the vicinity of the drilled bore and increase the probability of necrosis phenomenon. In this article, an analytical model to predict process temperature is presented based on Sui and Sugita model. This heat transfer model is the combination of a heat equilibrium equation for tool–chip system and a heat distribution equation for the bone itself where heat generation in tool’s tip is due to cutting frictional forces. In an analytical model, it is possible to use material properties of the bone and geometry of the tool; therefore, the calibration test is not necessary. In order to validate analytical model, experiments were done using bovine bone. Using response surface method, a second-order linear regression mathematical model is derived using experimental results. The effect of each individual parameter as well as their interactions on the output of the process was investigated. Within the range of the parameters studied in this article, with an increase in rotational speed, process temperature boosts up. Effect of feed rate is complicated due to the tool–bone contact time issue. While higher temperature is achieved in lower feed rates because of higher tool–bone contact time but higher temperature is observed with high feed rates due to an increase in force and friction. Optimized combination of the parameters to minimize temperature of 35.6 °C is tool diameter of 2.5 mm, rotational speed of 500 r/min and feed rate of 30 mm/min. Good correlation was observed between analytical and experimental results.

Research paper thumbnail of Investigation, sensitivity analysis, and multi-objective optimization of effective parameters on temperature and force in robotic drilling cortical bone

Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine

The bone drilling process is very prominent in orthopedic surgeries and in the repair of bone fra... more The bone drilling process is very prominent in orthopedic surgeries and in the repair of bone fractures. It is also very common in dentistry and bone sampling operations. Due to the complexity of bone and the sensitivity of the process, bone drilling is one of the most important and sensitive processes in biomedical engineering. Orthopedic surgeries can be improved using robotic systems and mechatronic tools. The most crucial problem during drilling is an unwanted increase in process temperature (higher than 47 °C), which causes thermal osteonecrosis or cell death and local burning of the bone tissue. Moreover, imposing higher forces to the bone may lead to breaking or cracking and consequently cause serious damage. In this study, a mathematical second-order linear regression model as a function of tool drilling speed, feed rate, tool diameter, and their effective interactions is introduced to predict temperature and force during the bone drilling process. This model can determine t...

Research paper thumbnail of Heat Source Modeling and Study on the Effect of Thickness on Residual Stress Distribution in Electron Beam Welding

Journal of Welding and Joining, 2017

In this study, the volumetric heat source in electron beam welding (EBW) is modeled through finit... more In this study, the volumetric heat source in electron beam welding (EBW) is modeled through finite element method taking advantage of ABAQUS software package. Since this welding method is being applied in plates with different thicknesses and also considering that residual stresses reduce the strength of these weldments, the effect of thickness in the distribution and magnitude of residual stresses after welding is studied. Regarding the vast application of Inconel 706 super-alloy in aerospace industries, this material was selected in the current research. In order to validate the finite element model, the obtained results were compared to those of other researchers in this area, and good agreement was observed. The simulation results revealed that increase in the plate thickness leads to increase in the residual stresses. In addition heat treatment in the base metal (before welding) increases the residual stresses significantly.

Research paper thumbnail of Comparative study of expert predictive models based on adaptive neuro fuzzy inference system, nonlinear autoregressive exogenous and Hammerstein–Wiener approaches for electrical discharge machining performance: Material removal rate and surface roughness

Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 2016

In this study, material removal rate (MRR) and surface roughness (Ra) in electrical discharge mac... more In this study, material removal rate (MRR) and surface roughness (Ra) in electrical discharge machining process have been modeled to make the process more efficient and reliable. First, adaptive neuro fuzzy inference system as one of the most used methods has been applied for prediction of material removal rate and Ra. Also a proposed method, that is, nonlinear modeling by system identification, has been applied to predict material removal rate and Ra. A group of electrical discharge machining experiments considering four input variables was conducted to collect dataset for training the predictive models. At the end, the comparison of predicted results from both approaches with experimental data shows that the new method has a much better performance than the adaptive neuro fuzzy inference system approach.

Research paper thumbnail of Experimental and finite element investigation of formability and failures in bi-layered tube hydroforming

Advances in Engineering Software, 2011

Optimization of the operating conditions is one of the most significant studies in the hydroformi... more Optimization of the operating conditions is one of the most significant studies in the hydroforming process, which affect the forming of successful components. In this work, a finite element model was established for bi-layered tube hydroforming process using ANSYS LS-DYNA pre-processor and LS-DYNA solver in order to predict the most efficient and acceptable operating condition for certain material properties and

Research paper thumbnail of Experimental and Numerical Analysis on TIG Arc Welding of Stainless Steel Using RSM Approach

Metals

This study involves the validating of thermal analysis during TIG Arc welding of 1.4418 steel usi... more This study involves the validating of thermal analysis during TIG Arc welding of 1.4418 steel using finite element analyses (FEA) with experimental approaches. 3D heat transfer simulation of 1.4418 stainless steel TIG arc welding is implemented using ABAQUS software (6.14, ABAQUS Inc., Johnston, RI, USA), based on non-uniform Goldak’s Gaussian heat flux distribution, using additional DFLUX subroutine written in the FORTRAN (Formula Translation). The influences of the arc current and welding speed on the heat flux density, weld bead geometry, and temperature distribution at the transverse direction are analyzed by response surface methodology (RSM). Validating numerical simulation with experimental dimensions of weld bead geometry consists of width and depth of penetration with an average of 10% deviation has been performed. Results reveal that the suggested numerical model would be appropriate for the TIG arc welding process. According to the results, as the welding speed increases,...

Research paper thumbnail of Statistical modeling and optimization of the EDM parameters on WC-6%Co composite through a hybrid response surface methodology-desirability function approach

This paper presents an integrated approach to the process modeling and multi-objective optimizati... more This paper presents an integrated approach to the process modeling and multi-objective optimization of electrodischarge machining (EDM) parameters on cobalt-bonded tungsten carbide composite (Tungsten CarbideCobalt alloy: WC/6%Co, Iso grade: K10) based on response surface methodology (RSM) coupled with desirability function (DF) technique. Four independent parameters, viz., discharge current (A), pulse on-time (B), duty cycle (C), and average gap voltage (D) were selected as the input variables to evaluate the process performance in terms of material removal rate (MRR), tool wear rate (TWR), and surface roughness (Ra). Facecentered central (FCC) composite design has been employed to plan and analyze the experiments. A comprehensive analysis of variance (ANOVA) at different significance levels of 1%, 5%, and 7% were done to fully identify the most influential parameters, and the adequacy of all fitted second order regression models were checked. To fully understand the characteristic...

Research paper thumbnail of Modeling and Investigation of the Wall Thickness Changes and Process Time in ThermoMechanical Tube Spinning Process Using Design of Experiments

Engineering, 2010

Tube spinning technology is one of the effective methods of manufacturing large diameter thin-wal... more Tube spinning technology is one of the effective methods of manufacturing large diameter thin-walled shapes. In this research, effects of major parameters of thermo mechanical tube spinning process such as preform's thickness, percentage of thickness reduction, mandrel rotational speed, feed rate, solution treatment time and aging treatment time on the wall thickness changes and process time in thermo-mechanical tube spinning process for fabrication of 2024 aluminum spun tubes using design of experiments (DOE), are studied. The statistical results are verified through some experiments. Results of experimental evaluation are analyzed by variance analysis and mathematic models are obtained. Finally using these models, input parameters for optimum production are achieved.

Research paper thumbnail of Finite-Volume Heat Transfer Model of the Nano Electrical Discharge Machining Process

Journal of Nanoelectronics and Optoelectronics, 2014

Research paper thumbnail of Computational Fluid Dynamic Simulation of the Nanoelectrical Discharge Machining Process

Nano, 2011

Electrical discharge machining (EDM) process is one of the advanced machining processes that can ... more Electrical discharge machining (EDM) process is one of the advanced machining processes that can machine the various complex shapes from all conductor and semiconductor materials. Wide and diverse applications of Micro-EDM process in microfabrication and micro-to nanominiaturization tendency is promising application of Nano-EDM process in nanofabrication. The Nano-EDM is a precise, sensitive and costly process. Therefore, simulation of nanocrater produced by each spark in this process prevents spending extra time and cost to perform Nano-EDM process through trial and error method. In this paper nanocrater machined by the Nano-EDM process on a gold nanofilm is simulated under practically experimental conditions. Radius, depth and volume of the nanocrater are evaluated versus process conditions (average power and pulse duration) and workpiece thickness (50 nm, 100 nm and 300 nm). It is observed that radius of the nanocrater is increased exponentially with increasing spark pulse duration. Also, depth, volume of the removed material from the workpiece surface and material removal rate (MRR) are increased with increasing consumed energy by each spark. By increasing thickness of the nanofilm, volume of the removed material and dimensions of the nanocrater are decreased.

Research paper thumbnail of Investigation of effective parameters on surface roughness in thermomechanical tube spinning process

International Journal of Material Forming, 2009

Tube spinning process is recognized as an effective process for fabricating of thin wall cylindri... more Tube spinning process is recognized as an effective process for fabricating of thin wall cylindrical parts, with precision tolerances, high surface quality and desired mechanical property. In this research, the influences of major parameters of thermomechanical tube spinning process such as preform thickness, percentage of thickness reduction, mandrel rotational speed, feed rate of rollers, solution treatment time and aging treatment time on surface roughness for fabricating of 2024 aluminum spun tubes using design of experiments are studied. Experimental data are analyzed by analysis of variance (Anova) and empirical models of surface roughnesses are developed. It is found that deeper percentage of thickness reduction with thicker preform thickness, slower feed rate of rollers and mandrel rotational speed and higher solution treatment time and aging treatment time are advantageous for obtaining smoother surface.

Research paper thumbnail of Numerical and experimental study of flowing and spreading of silver-based filler metal droplet on different substrates during laser brazing process

The International Journal of Advanced Manufacturing Technology, 2015

Research paper thumbnail of Statistical Investigation into the Effects of Electro-Discharge Machining Parameters on WC/6%Co Composite-Part 1: Modeling through Response Surface Methodology (RSM)

International Journal of Advanced Materials Manufacturing and Characterization, 2013

Response surface methodology (RSM), Tungsten carbide cobalt composite (WC-Co).

Research paper thumbnail of ‫بررسي‬ ‫ماشينکار‬ ‫کمپرسور‬ ‫پره‬ ‫ريشه‬ ‫ي‬ ‫موتور‬ ‫گاز‬ ‫توربين‬ ‫ي‬ ‫فر‬ ‫با‬ ‫آ‬ ‫الکتريک‬ ‫تخليه‬ ‫يند‬ ‫ي‬ ‫سيم‬ ‫ي‬ ‫قريشي‬ ‫مجيد‬ Investigation of Machining of Compressor Blade Root using Wire Electrical Discharge Process

Manufacturing of blades in air turbine motors according to complicated shape and critical working... more Manufacturing of blades in air turbine motors according to complicated shape and critical working conditions needs a high technology. The root of blade under applied forces should have high surface quality and dimensional accuracy in comparison with the other blade components. In this study, the surface quality due to different types of available wire-cut machines for machining of compressor blade root has been investigated. To this end some samples has been machined by different wire-cut machines. Afterwards the different components of surface integrity (such as surface roughness, surface topography, hardness, thickness of affected surface layers, microcrackes and pits, residual stresses) has been studied. Finally, the machining of the root of compressor blade with this process has been discussed and concluded.

Research paper thumbnail of Sensitivity analysis of material removal rate in dry electro-discharge machining process

Dry electro discharge machining is one of the newest machining processes on which studies are rem... more Dry electro discharge machining is one of the newest machining processes on which studies are remarkably expanding. Its advantages include being environment friendly, low process costs, simple tools and equipment, optimized machining parameters and cheap dielectric. Considering fast expansion of this machining process, its optimized performance is desirable. Considering the material removal rate and the addition of the gas pressure and electrode rotational speed comparing to the conventional spark machining makes the analysis of effective parameters on material removal rate necessary for improving the process performance. In this study, the effect of different parameters such as machining gap voltage, electro discharge current, pulse on-time, pulse on-time to pulse off time ratio, dielectric gas pressure and tool rotational speed on material removal rate were studied using Sobol statistical sensitivity analysis method. In comparison with the other methods, it possesses the advantage...

Research paper thumbnail of Experimental Modelling of Nd:YAG Laser Percussion Drilling Process of Ti6Al4V Alloy

Research paper thumbnail of Numerical Investigation and Enhancement of Flushing Performance in the Micro-Electro Discharge Machining by Considering the Hole Depth and Dielectric Fluid

flushing of machining gap is one of the most crucial issues in the micro-EDM that not only remove... more flushing of machining gap is one of the most crucial issues in the micro-EDM that not only removes debris from the machining gap, but it also increases the machining efficiency. Identification of dielectric flow pattern provides a good perspective for its user to enhance the flushing performance. In this paper, the effects of the hole depth and dielectric fluid parameters on the flushing in micro-EDM are studied on the flushing in micro-EDM. Three different levels of 5, 10 and 15 mm for depth are considered, while deionized water, kerosene, and EDM-30 oil are chosen as dielectrics. To find out the effect of these parameters on flushing, computational fluid dynamics (CFD) based on boundary volume method is applied to solve the fluid flow in the flushing gap. To verify the numerical simulation model, a comparison was conducted between the results obtained in this work and the experimental and numerical results of the available literatures. The maximum difference between the results of...

Research paper thumbnail of Modelling and optimisation of temperature and force behaviour in high-speed bone drilling

Biotechnology & Biotechnological Equipment

Bone drilling and implantation are important in orthopaedic surgery, dentistry and also fracture ... more Bone drilling and implantation are important in orthopaedic surgery, dentistry and also fracture treatment. In many cases, due to the rise in temperature during bone drilling (higher than 47 C) and low conductivity of bone, thermal necrosis occurs. There is also risk of drill fracture due to the excessive thrust force. Despite many studies on the effect of different parameters on bone drilling temperature and force, there is still no clarity about the influence of the tool rotational speed and feed rate on the temperature and force responses. The aim of this study was to test and optimise the conditions in high-speed bone drilling, process force and temperature simultaneously. The results demonstrated that high-speed drilling is a suitable method for decreasing process temperature and force, and the rotational speed, feed rate and tool diameter were the most important factors in the high-speed bone drilling processes. Using a statistical method to model and optimise the process, a second-order model was developed to predict the behaviour of process temperature and thrust force in high-speed drilling. The optimised values were a rotational speed of 11778 rpm, feed rate of 50 mm/min and tool diameter of 2 mm, where the process force and temperature were 15.85 N and 33.4 C, respectively. Therefore, in high-speed bone drilling, the process thrust force and temperature decline, and the low effect of feed rate on temperature enables an increase in the speed of operation in robotic surgery.

Research paper thumbnail of Optimum design of vibratory electrode in micro-EDM process

The International Journal of Advanced Manufacturing Technology

Micro-electro discharge machining (EDM) has a crucial role in fabrication of parts such as molds.... more Micro-electro discharge machining (EDM) has a crucial role in fabrication of parts such as molds. One of the most challenging aspects of EDM process relates to flushing of debris. Increasing the material removal rate causes significant enhancement in EDM process. In this study, new numerical approach for enhancing flushing is proposed. A model of vibratory electrode and dielectric flow pattern is validated with theoretical and experimental results. Next, the effect of vibratory electrode geometry and its material properties on flushing of debris is investigated. To this end, design of experiment method is applied to find optimum vibratory electrode shape and material. At first step, vibrational analysis is performed for electrodes to find mode shapes and their corresponding frequency utilizing the finite element method. Vibrational results have good agreement with theoretical ones that are presented in literatures. Next, frequency response function analysis is done for vertical excitation force to find out displacements of electrodes in longitudinal modes. The results of these simulations are utilized to construct 3D computational fluid dynamic (CFD) models to find velocity distribution on gap space between electrode and work piece. Full factorial design is used to evaluate electrode’s parameters. The results from these simulations are studied to achieve best electrode shape that is able to flush the gap flow significantly. Finally, dielectric flow regime for optimum electrode shape is surveyed.

Research paper thumbnail of Sensitivity analysis of temperature and force in robotic bone drilling process using Sobol statistical method

Biotechnology & Biotechnological Equipment

The bone drilling process is indispensable in orthopaedic surgeries and treating bone breakages. ... more The bone drilling process is indispensable in orthopaedic surgeries and treating bone breakages. It is also very important in dentistry and bone sampling operations. Bone is a very complex material and the process of drilling is very sensitive. Thus, bone drilling is one of the most important, common in the field of biomedical engineering. The bone drilling process can be promoted using automatic drilling machines and surgery-assisting robots. The problematic issue during operation is the high increase in drilling process temperature (higher than 47 C) which leads to the so-called 'thermal necrosis' or cell death, and local burn in bone tissue. Furthermore, imposing higher forces to bone might yield to breaking or cracking, and consequently causes serious damages in bone. In this paper, the tool rotational speed, feed ratio and tool diameter were taken into account as process input parameters, and process temperature and thrust force were taken as output parameters. Design of experiments using response surface methodology was followed. Then, second linear governing equation was assigned to the model and its accuracy was evaluated. Later, Sobol statistical sensitivity analysis was used to ascertain the effect of process input parameters on process temperature and force. The results showed that among all effective input parameters, the tool rotational speed, feed rate and tool diameter have the highest influence respectively on process temperature and force. The behaviour of each output parameter with variation in each input parameter was further investigated.

Research paper thumbnail of Analytical and experimental study of effective parameters on process temperature during cortical bone drilling

Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine

Bone drilling process is a prominent step of internal fixation in orthopedic surgeries. Process f... more Bone drilling process is a prominent step of internal fixation in orthopedic surgeries. Process forces, leading to chip production, produce heat in the vicinity of the drilled bore and increase the probability of necrosis phenomenon. In this article, an analytical model to predict process temperature is presented based on Sui and Sugita model. This heat transfer model is the combination of a heat equilibrium equation for tool–chip system and a heat distribution equation for the bone itself where heat generation in tool’s tip is due to cutting frictional forces. In an analytical model, it is possible to use material properties of the bone and geometry of the tool; therefore, the calibration test is not necessary. In order to validate analytical model, experiments were done using bovine bone. Using response surface method, a second-order linear regression mathematical model is derived using experimental results. The effect of each individual parameter as well as their interactions on the output of the process was investigated. Within the range of the parameters studied in this article, with an increase in rotational speed, process temperature boosts up. Effect of feed rate is complicated due to the tool–bone contact time issue. While higher temperature is achieved in lower feed rates because of higher tool–bone contact time but higher temperature is observed with high feed rates due to an increase in force and friction. Optimized combination of the parameters to minimize temperature of 35.6 °C is tool diameter of 2.5 mm, rotational speed of 500 r/min and feed rate of 30 mm/min. Good correlation was observed between analytical and experimental results.

Research paper thumbnail of Investigation, sensitivity analysis, and multi-objective optimization of effective parameters on temperature and force in robotic drilling cortical bone

Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine

The bone drilling process is very prominent in orthopedic surgeries and in the repair of bone fra... more The bone drilling process is very prominent in orthopedic surgeries and in the repair of bone fractures. It is also very common in dentistry and bone sampling operations. Due to the complexity of bone and the sensitivity of the process, bone drilling is one of the most important and sensitive processes in biomedical engineering. Orthopedic surgeries can be improved using robotic systems and mechatronic tools. The most crucial problem during drilling is an unwanted increase in process temperature (higher than 47 °C), which causes thermal osteonecrosis or cell death and local burning of the bone tissue. Moreover, imposing higher forces to the bone may lead to breaking or cracking and consequently cause serious damage. In this study, a mathematical second-order linear regression model as a function of tool drilling speed, feed rate, tool diameter, and their effective interactions is introduced to predict temperature and force during the bone drilling process. This model can determine t...

Research paper thumbnail of Heat Source Modeling and Study on the Effect of Thickness on Residual Stress Distribution in Electron Beam Welding

Journal of Welding and Joining, 2017

In this study, the volumetric heat source in electron beam welding (EBW) is modeled through finit... more In this study, the volumetric heat source in electron beam welding (EBW) is modeled through finite element method taking advantage of ABAQUS software package. Since this welding method is being applied in plates with different thicknesses and also considering that residual stresses reduce the strength of these weldments, the effect of thickness in the distribution and magnitude of residual stresses after welding is studied. Regarding the vast application of Inconel 706 super-alloy in aerospace industries, this material was selected in the current research. In order to validate the finite element model, the obtained results were compared to those of other researchers in this area, and good agreement was observed. The simulation results revealed that increase in the plate thickness leads to increase in the residual stresses. In addition heat treatment in the base metal (before welding) increases the residual stresses significantly.

Research paper thumbnail of Comparative study of expert predictive models based on adaptive neuro fuzzy inference system, nonlinear autoregressive exogenous and Hammerstein–Wiener approaches for electrical discharge machining performance: Material removal rate and surface roughness

Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 2016

In this study, material removal rate (MRR) and surface roughness (Ra) in electrical discharge mac... more In this study, material removal rate (MRR) and surface roughness (Ra) in electrical discharge machining process have been modeled to make the process more efficient and reliable. First, adaptive neuro fuzzy inference system as one of the most used methods has been applied for prediction of material removal rate and Ra. Also a proposed method, that is, nonlinear modeling by system identification, has been applied to predict material removal rate and Ra. A group of electrical discharge machining experiments considering four input variables was conducted to collect dataset for training the predictive models. At the end, the comparison of predicted results from both approaches with experimental data shows that the new method has a much better performance than the adaptive neuro fuzzy inference system approach.

Research paper thumbnail of Experimental and finite element investigation of formability and failures in bi-layered tube hydroforming

Advances in Engineering Software, 2011

Optimization of the operating conditions is one of the most significant studies in the hydroformi... more Optimization of the operating conditions is one of the most significant studies in the hydroforming process, which affect the forming of successful components. In this work, a finite element model was established for bi-layered tube hydroforming process using ANSYS LS-DYNA pre-processor and LS-DYNA solver in order to predict the most efficient and acceptable operating condition for certain material properties and

Research paper thumbnail of Experimental and Numerical Analysis on TIG Arc Welding of Stainless Steel Using RSM Approach

Metals

This study involves the validating of thermal analysis during TIG Arc welding of 1.4418 steel usi... more This study involves the validating of thermal analysis during TIG Arc welding of 1.4418 steel using finite element analyses (FEA) with experimental approaches. 3D heat transfer simulation of 1.4418 stainless steel TIG arc welding is implemented using ABAQUS software (6.14, ABAQUS Inc., Johnston, RI, USA), based on non-uniform Goldak’s Gaussian heat flux distribution, using additional DFLUX subroutine written in the FORTRAN (Formula Translation). The influences of the arc current and welding speed on the heat flux density, weld bead geometry, and temperature distribution at the transverse direction are analyzed by response surface methodology (RSM). Validating numerical simulation with experimental dimensions of weld bead geometry consists of width and depth of penetration with an average of 10% deviation has been performed. Results reveal that the suggested numerical model would be appropriate for the TIG arc welding process. According to the results, as the welding speed increases,...

Research paper thumbnail of Statistical modeling and optimization of the EDM parameters on WC-6%Co composite through a hybrid response surface methodology-desirability function approach

This paper presents an integrated approach to the process modeling and multi-objective optimizati... more This paper presents an integrated approach to the process modeling and multi-objective optimization of electrodischarge machining (EDM) parameters on cobalt-bonded tungsten carbide composite (Tungsten CarbideCobalt alloy: WC/6%Co, Iso grade: K10) based on response surface methodology (RSM) coupled with desirability function (DF) technique. Four independent parameters, viz., discharge current (A), pulse on-time (B), duty cycle (C), and average gap voltage (D) were selected as the input variables to evaluate the process performance in terms of material removal rate (MRR), tool wear rate (TWR), and surface roughness (Ra). Facecentered central (FCC) composite design has been employed to plan and analyze the experiments. A comprehensive analysis of variance (ANOVA) at different significance levels of 1%, 5%, and 7% were done to fully identify the most influential parameters, and the adequacy of all fitted second order regression models were checked. To fully understand the characteristic...

Research paper thumbnail of Modeling and Investigation of the Wall Thickness Changes and Process Time in ThermoMechanical Tube Spinning Process Using Design of Experiments

Engineering, 2010

Tube spinning technology is one of the effective methods of manufacturing large diameter thin-wal... more Tube spinning technology is one of the effective methods of manufacturing large diameter thin-walled shapes. In this research, effects of major parameters of thermo mechanical tube spinning process such as preform's thickness, percentage of thickness reduction, mandrel rotational speed, feed rate, solution treatment time and aging treatment time on the wall thickness changes and process time in thermo-mechanical tube spinning process for fabrication of 2024 aluminum spun tubes using design of experiments (DOE), are studied. The statistical results are verified through some experiments. Results of experimental evaluation are analyzed by variance analysis and mathematic models are obtained. Finally using these models, input parameters for optimum production are achieved.

Research paper thumbnail of Finite-Volume Heat Transfer Model of the Nano Electrical Discharge Machining Process

Journal of Nanoelectronics and Optoelectronics, 2014

Research paper thumbnail of Computational Fluid Dynamic Simulation of the Nanoelectrical Discharge Machining Process

Nano, 2011

Electrical discharge machining (EDM) process is one of the advanced machining processes that can ... more Electrical discharge machining (EDM) process is one of the advanced machining processes that can machine the various complex shapes from all conductor and semiconductor materials. Wide and diverse applications of Micro-EDM process in microfabrication and micro-to nanominiaturization tendency is promising application of Nano-EDM process in nanofabrication. The Nano-EDM is a precise, sensitive and costly process. Therefore, simulation of nanocrater produced by each spark in this process prevents spending extra time and cost to perform Nano-EDM process through trial and error method. In this paper nanocrater machined by the Nano-EDM process on a gold nanofilm is simulated under practically experimental conditions. Radius, depth and volume of the nanocrater are evaluated versus process conditions (average power and pulse duration) and workpiece thickness (50 nm, 100 nm and 300 nm). It is observed that radius of the nanocrater is increased exponentially with increasing spark pulse duration. Also, depth, volume of the removed material from the workpiece surface and material removal rate (MRR) are increased with increasing consumed energy by each spark. By increasing thickness of the nanofilm, volume of the removed material and dimensions of the nanocrater are decreased.

Research paper thumbnail of Investigation of effective parameters on surface roughness in thermomechanical tube spinning process

International Journal of Material Forming, 2009

Tube spinning process is recognized as an effective process for fabricating of thin wall cylindri... more Tube spinning process is recognized as an effective process for fabricating of thin wall cylindrical parts, with precision tolerances, high surface quality and desired mechanical property. In this research, the influences of major parameters of thermomechanical tube spinning process such as preform thickness, percentage of thickness reduction, mandrel rotational speed, feed rate of rollers, solution treatment time and aging treatment time on surface roughness for fabricating of 2024 aluminum spun tubes using design of experiments are studied. Experimental data are analyzed by analysis of variance (Anova) and empirical models of surface roughnesses are developed. It is found that deeper percentage of thickness reduction with thicker preform thickness, slower feed rate of rollers and mandrel rotational speed and higher solution treatment time and aging treatment time are advantageous for obtaining smoother surface.

Research paper thumbnail of Numerical and experimental study of flowing and spreading of silver-based filler metal droplet on different substrates during laser brazing process

The International Journal of Advanced Manufacturing Technology, 2015

Research paper thumbnail of Statistical Investigation into the Effects of Electro-Discharge Machining Parameters on WC/6%Co Composite-Part 1: Modeling through Response Surface Methodology (RSM)

International Journal of Advanced Materials Manufacturing and Characterization, 2013

Response surface methodology (RSM), Tungsten carbide cobalt composite (WC-Co).