mohammad honarpisheh

In this research, a new technique for severe plastic deformation (SPD) was proposed, entitled as non-uniform simple shear extrusion (NUSSE). The larger strains can be obtained in the non-uniform simple shear extrusion (NUSSE) method without repetition of the process. But, in pure shear extrusion (PSE) and simple shear extrusion (SSE) processes, to achieve larger strains, it is necessary to repeat the processes. In this study, the technique was investigated experimentally and numerically using ABAQUS software. The maximum plastic strain, inhomogeneity in deformation, filling fraction and micro-hardness parameters were researched after NUSSE process. Also, the obtained results were compared to the SSE and PSE processes. After this technique, due to the specific design of deformation channel, filling fraction was increased by about 44.92% and 41.84% in comparison with SSE and PSE processes, respectively. Also, the micro-hardness was significantly increased compared to annealing process.

The significance of sheet metal drilling within industrial applications is widely recognized, particularly for its critical role in creating durable connections in sheet components. This process, especially when implemented through friction drilling, not only minimizes material waste by generating connecting flanges bush shape but also enhances the robustness of the connections. In this study, we used the ABAQUS finite element software (FEM) to simulate and design the friction drilling process on sheets of three different thicknesses, employing three rotational speeds and three feed rates. The analysis was conducted using Design Expert statistical software, which integrated response surface methodology (RSM) and data analysis to thoroughly investigate the process forces. Aluminum AA 7075 was selected for the study due to its extensive use in the automotive, manufacturing, military, and aerospace organizations, highlighting its industrial relevance. The findings suggest that optimizing the machining force leads to more favorable conditions within the process. The optimal parameters were determined to include the highest rotational speed, the lowest feed rate, and the smallest sheet thickness. These conditions promote higher temperatures that facilitate better material flow. An increase in thickness was also found to correlate with higher temperatures. Additionally, the study addressed the significant industrial challenge of residual stresses and their effects on component defects, a topic not previously explored through finite element simulations in this context. This research contributes new insights into the implications of residual stresses in various directions for friction drilling processes.

Tubular channel angular pressing (TCAP) process is one of the new methods to produce tubes with very good mechanical and microstructural properties. The trapezoidal channel cross-section is preferred in this process due to its high strain homogeneity and low required load compared to other channel cross-sections. In this research, the TCAP process with a trapezoidal channel cross-section was modeled using different channel and curvature angles in Abaqus software and then one pass of the process was applied to annealed aluminum 6061 samples. After that, the effect of these angles on the effective strain as well as process load was shown. For validation, the results of the finite element method (FEM) were compared and analyzed with the analytical model. The results of the processed samples showed that reducing the channel and curvature angles increases the applied effective strain. By increasing the curvature angle, the strain homogeneity has increased, and as a result, the hardness and microstructure homogeneity have increased. The process load has also decreased with the increase of channel and curvature angles. Also, there was a good agreement between the FEM results and the analytical model.

Surface Mechanical Attrition Treatment (SMAT) is recognized as an effective technology for enhancing hardness and surface abrasion resistance. This study examined the influence of SMAT on the microstructure, surface roughness, hardness, and wear behavior of the AZ31 magnesium alloy. For the experiments, steel balls of different diameters – 3.2mm, 4mm, and 5.6mm – were used to perform the SMAT process, which was consistently timed at 8.5 minutes. Detailed analyses of the resultant microstructures were then conducted using tools such as a scanning electron microscope and X-ray diffraction. The hardness and wear were measured using the Vickers and the disk pin methods, respectively. It was observed that the SMAT process significantly reduced the grain size on the sample surfaces. For example, when a steel ball with a diameter of 5.6mm was utilized, the grain size was reduced from 225nm to just 96nm. The process also led to a substantial increase in hardness, with measurements rising from 65 HV to 190 HV, once again when a steel ball of 5.6mm diameter was utilized. Furthermore, the SMAT process, when executed with a tool diameter of 5.6mm, eliminated weight loss in the wear test, which had been previously recorded at 0.26mg, indicating an increase in surface abrasion resistance. An observed correlation suggested that as the tool diameters increased, the abrasion resistance of the surface improved. Abrasion was adhesive on untreated samples; on treated samples, it was ridged and scratched. However, as the tool diameter—and consequently, the surface hardness—increased, the scratches were seen to reduce gradually.

In any case, macroscale shaping cannot be transferred to microscale due to the size effect. There are different parameters to evaluate small-scale forming. In this article, the effect of flow stress and topography in two states of lubrication and without lubrication for T2 copper micro cylinder has been investigated using the numerical solution and prediction of a trained neural network. An artificial neural network model has been presented to investigate the flow stress and the effect of friction with the miniaturization of the copper microcylinder. The results show that the flow stress decreases with decreasing the initial specimen diameter in both lubrication conditions, and the flow stress decreases by 30 MPa with the initial specimen diameter decreasing from 8 mm to 1 mm. The friction factor increases obviously with decreasing the initial specimen diameter in the case of lubricating with castor oil, and the friction factor increases by 0.11 with the initial specimen diameter decreasing from 8 mm to 1 mm. However, the tribology size effect is not found in the case without lubrication. The reasons for the flow stress and tribology size effects were also discussed. The good matching of outputs and objectives in the regression graphs shows that the response of the neural network is satisfactory.

One of the forming pipes methods is the rotary draw bending process. Today, bending of thin-walled pipes with low radius of curvature is widely used in the automotive, military and aerospace industries, which is used to bend high-strength pipes. In this paper, at first the necessary models were created to simulate the bending process of the rotary pipe, and then the necessary mechanical and physical properties for stainless steel 304 and elastomers were determined. Then, experimental and numerical study of the forming force and changes in pipe wall thickness were performed. The process simulation was analytically performed using polyurethane elastomeric mandrels and nitrile rubber based on ABAQUS finite element software on 304 steel. The results show a good agreement between simulation and experimental results. Finally, the effects of process parameters including mandrel type, pipe diameter and bending radius were analyzed on the maximum forming force by factorial analysis. The results showed that the maximum forming force for both types of mandrel materials is obtained for pipes with small diameter and high curvature radius. Also, the bending forces increase 5 times by 30%increasing the bending radius, for pipes with smaller diameters. In addition, in equal diameter and radius of bending, the bending forces in the case of using polyurethane mandrel are 25% more than nitrile mandrel.

In this study, constraint groove pressing (CGP) process and ultrasonic assisted CGP (UCGP) process were investigated on the process forces, mechanical properties of the sheet, including hardness and tensile tests and grain size. Pure copper sheets were used as samples in this research. Samples were tested both with and without ultrasonic vibrations for mechanical properties and grain size up to 4 passes. The results of tensile tests showed that by applying CGP process, the strength of the samples increases significantly in the first two passes and then decreases. Hardness test results showed an increase which had the highest rate after the first pass. As expected, CGP process was very effective to create fine-grained metal structure. Also, process forces were investigated in both CGP and UCGP processes and then compared in 3 methods of 2 dimension (plane strain) simulation, 3 dimension simulation and experimental examination. After all, a good agreement was achieved.

Nowadays, the role of light weight materials has grown up in important industries such as aerospace and biomechanics, but before the appliance, their strength should be increased. A modern way to increase this factor along with the lightweight factoris using bimetal sheets, hence, the design of multilayer sheets has been very much considered recently. In this study, explosive welded Cu/St/Cu multilayer sheets were used in the incremental forming process to determine the springback phenomenon on different layers. The results indicated that rotational speed, feeding rate, and vertical step parameters can affect spring back in single point incremental forming process (SPIF).Three levels of vertical step size, tool rotational speed, and feed rate have been considered as the input process parameters and spring back as the output.In order to design a better experiment and analyze the data, the Taguchi method was selected on the basis of DOEin Mini-Tab software andthe results have been analyzed by two states. In the first state,the value which was closest to the nominal value is considered to be the optimal result which obtained for spring back angles with parameters of 0.75 mm for the vertical step down, 200 rpm for the rotational speed and 500 and 1000 mm/min for the feeding rate. In the second state, the least amount is considered as the optimal result in which the values of 0.5 and 1 mm of the vertical step down, 150 and 100 rpm of the rotational speed, and 1500 and 500 mm/min of the feeding rate formed the optimal outcome.

One of the methods for making prototypes is incremental forming process. In this method, the forming tool, performs a pre-programmed movement by the CNC machine and runs the desired path. This modernization process is used in the automotive, aerospace, military, medical and other industries. One of the most influential parameters in this process is forming tool. This parameter is effective in forming forces, surface roughness, sheet formability and thickness distribution. In this study, the forming tool was investigated and rotating geometry tool was compared with a rigid tool. Also, the effects of step down, feed rate and spindle speed were investigated on the forming force, surface roughness and thickness distribution by comparing mentioned forming tools. The results indicate that the forming forces, sheet surface quality and thickness changes increase with increasing step down and feed rate. Using the rotary tools improves the forming forces, surface roughness and thickness distribution rather than the non-rotating tool.

Equal channel angular rolling (ECAR) process is one of the severe plastic deformation (SPD) methods that have been used to make ultra-fine grain (UFG) materials with improving the mechanical properties of samples. After performing the process at several paths, a large strain is applied to the material that can cause decreasing the grain size and improving the mechanical and physical properties of the metal. In this paper, the effects of annealing thermal treatment at various temperatures and times on the weld bond of bimetal explosive welded stainless steel-copper sheet during the equal channel angular rolling process have been investigated. For this purpose, after performing the ECAR process and thermal treatment on bimetal sheet, hardness and welding interface were studied. The results showed that performing thermal treatment at different temperatures caused the formation of intermetallic compounds in the weld bond, which would change the hardness of this region. Also, increasing the annealing time increased the thickness of the weld bond.

Nowadays, the role of light weight materials has grown up in important industries such as aerospace and biomechanics, but before the appliance, their strength should be increased. A modern way to increase this factor along with the lightweight factoris using bimetal sheets, hence, the design of multilayer sheets has been very much considered recently. In this study, explosive welded Cu/St/Cu multilayer sheets were used in the incremental forming process to determine the springback phenomenon on different layers. The results indicated that rotational speed, feeding rate, and vertical step parameters can affect spring back in single point incremental forming process (SPIF).Three levels of vertical step size, tool rotational speed, and feed rate have been considered as the input process parameters and spring back as the output.In order to design a better experiment and analyze the data, the Taguchi method was selected on the basis of DOEin Mini-Tab software andthe results have been analyzed by two states. In the first state,the value which was closest to the nominal value is considered to be the optimal result which obtained for spring back angles with parameters of 0.75 mm for the vertical step down, 200 rpm for the rotational speed and 500 and 1000 mm/min for the feeding rate. In the second state, the least amount is considered as the optimal result in which the values of 0.5 and 1 mm of the vertical step down, 150 and 100 rpm of the rotational speed, and 1500 and 500 mm/min of the feeding rate formed the optimal outcome.

Incremental sheet metal forming is one of methods more innovation in science and industrial zone. The purpose of this research is the study of influence of factors such as tool diameter, step down, rotation speed and feed rate on metallurgical properties of explosive-welded Al/Cu/Al multilayer. In order to this purpose, a sample of explosive-welded Al/Cu/Al multilayer was produced. Then, a statistical model (RSM) was used for the experimental plan (with these variables) to determine the runs of experiment (or selected points). Next, forces and times values of sheet metal forming were measured. The experimental results showed that force and time forming of Al/Cu/Al multilayer is highly sensitive to factors like step down and feed rate. Also the most effective coefficient on the incremental forming is belonged to step down factor that showed it is very important in machining parameters. Finally, by using coefficient estimates of (RSM) model, relation between input variables and response was obtained. Finally, this model was predicted the optimum design points of machining parameters.

Compound casting refers to a process that used to produce bimetals. This study investigates the interface of Mo40/C93200 that is produced by compound casting process. In this research, molten bronze is poured around steel core, interaction between liquid and solid creates a diffusion zone and followed by a transition layer which leads to the creation of diffused region between the interfaces of metal layers. The results of micro-hardness and macro hardness used to complete the studies. The results of the hardness of the Mo40 alloy revealed that the micro-hardness of the alloy was almost 308 Vickers which this amount of hardness confirms the ferrite-pearlite state of microstructures. The results of metallography revealed that the boundary between steel and bronze alloys due to the difference in electric potential during etching evolved a galvanic cell and one section formed as the cathode and the other section as the anode. In this situation steel was corroding and bronze was protecting. As well as, the results of SEM show that the boundaries between two alloys have an acceptable adhesion and the strength of interface is sufficient. The result of tensile test indicates that the final yield strength was about 800 MPa and the elongation increases by 2%, which is an acceptable value. It is also observed that the failure is a soft defect type and a sufficient connection between steel and bronze is formed.

Equal channel angular rolling (ECAR) process is one of the severe plastic deformation (SPD) methods that have been used to make ultra-fine grain (UFG) materials with improving the mechanical properties of samples. After performing the process at several paths, a large strain is applied to the material that can cause decreasing the grain size and improving the mechanical and physical properties of the metal. In this paper, the effects of annealing thermal treatment at various temperatures and times on the weld bond of bimetal explosive welded stainless steel-copper sheet during the equal channel angular rolling process have been investigated. For this purpose, after performing the ECAR process and thermal treatment on bimetal sheet, hardness and welding interface were studied. The results showed that performing thermal treatment at different temperatures caused the formation of intermetallic compounds in the weld bond, which would change the hardness of this region. Also, increasing the annealing time increased the thickness of the weld bond.

Single point incremental sheet metal forming is a sheet metal forming process that forms products without the complex dies and tools with low cost. In this study, the incremental sheet metal forming process has been experimentally investigated on the explosively-welded Al/Cu bimetal sheets. Also, the effects of process parameters, such as arrangement of layer`s bimetal, tool diameter and tool path were investigated on the forming force, thickness distribution, formability and roughness. At first, the bimetals were produced by explosive welding process. Then, two tool diameters, step and spiral tool paths and layer arrangement were chosen as input parameters. The results showed that the forming force increases with increasing the tool diameter and using aluminum as a top layer (contact with tool). Also, using spiral tool path increases the average forming force and decreases the maximum thickness changing. The formability increases with increasing the tool diameter and using the copper as top layer with spiral tool path.

Measurement of fracture toughness is one of the quality control parameter in rail manufacturing process. Fracture toughness value is needed for designing the rail lines, analysis of defects and other common prevalent works in mechanical engineering. The goal of this research is to introduce a relation for measuring fracture toughness of rail materials with grade R260 by Charpy V-notch number. At first the fracture toughness of rail material has been determined by 3-point bending technique according to ASTM E399 in ambient temperature. The fracture energies have been measured by Charpy impact test and it has been illustrated that fracture energies have no significant change in the tests temperature limit. Relations between the chemical analysis and mechanical properties have been studied and compared with results of the other researcher. Uniaxial tension test, analysis of chemical composite, metallography and hardness test have been carried out to better study of the process. Finally a relation to connect the Charpy V-notch number and fracture toughness has been introduced and the fracture toughness of the rails material over the impact test temperature limit has been calculated. Good agreement between calculated results and result of 3-pint bending test indicate appropriate accuracy of the introduced equation.

Metal spinning as a kind of manufacturing process has capability to shape hollow components. In present work shear spinning process is used to formplates into conical shapes. Moreover, the aim of this research is to demonstrate the impact of the process parameters (i.e. feeding rate and spindle speed) on wall thickness. This approachwas done by experimental and finite elements method. The results illustrated that wall thickness decreases while feeding rate increases in spinning process. The experimental results confirm the Finite element analysis (FEA) results during thickness evaluations so this shows that FEA results are reliable for this specific case. The results of analysis reveals that the best condition for spinning is for feeding rate of 40 mm/min and spindle speed of 50 rpm in which highest thickness of 1mm is obtained. In consequence, the findings also illustrated that by decreasing the feeding rate and spindle speed, higher thickeners can be observed during shear spinning process.

Equal channel angular rolling (ECAR) process is one of the methods that have been used to make ultra-fine materials by imposing severe plastic deformation. After repeating the process several times, a large effective strain is applied to the sample that can cause decreasing the grain size and improving the mechanical and physical properties of the metal. In this study, thermal conductivity of the samples that were produced by ECARwas investigated experimentally. Accordingly, the strips of aluminum alloy 3003 were ECARed up to 10 passes through route-A and route C. The effect of number of ECAR pass and routes of ECAR process (A and C) were investigated. Furthermore, tensile behavior and micro-hardness of ECARed samples werestudied.According to the results,the thermal conductivity of samples increased up to definite pass and raised to its maximum value, then had an oscillatory trend up to tenth pass. Although this improvement of the thermal conductivitywasn’t significantly, but the improvement of yield and ultimate strength and micro-hardness of the samples in passes associated with the maximum thermal conductivity, were meaningfully and so,this ECARed alloys can be used in harder situation.

Equal channel angular rolling (ECAR) is a severe plastic deformation method that covered plastic deformation of sheets. In this study, effects of ECAR route shave been investigated on the mechanical and microstructure properties of explosive-welded Al-Cu bimetal. At first, the explosive welding process has been performed to prepare the Al-Cu bimetals. Then, to relieve the stress and preparing of samples for ECAR process, the annealing process of the samples was done. Finally, the ECAR process was performed on the samples in two routes A and C. Results showed that yield and tensile strengths and micro hardness of ECARed samples significantly increased with increasing the number of passes, whereas their ductility decreased. The yield strength of bimetals has been increased from 80 MPa to 100 MPa and 130 MPa at the routes A and C, respectively. Also, with increasing the number of ECAR passes, the grain size of the ECARed bimetals decreased to about 2μm.