The present paper is the second part of a previously published overview entitled “ten years of severe plastic deformation (SPD) in Iran”. Part I concentrates on the equal channel angular pressing (ECAP). In this part, the focus is on the accumulative roll bonding (ARB) because, currently, Iran is ranked the first in the world by the total number of publications in this field. In the present section, the emphasis is not on the microstructure and ultrafine-grained materials produced by ARB. Instead, its focus is on several aspects of ARB to which small attention has been paid so far. The impact and contribution of Iran to each category is evaluated in comparison to researchers from other countries. The main interest of Iranian researchers in the field of ARB is to fabricate the composite materials, particularly metal matrix composites (MMCs). The Iranian researchers were the first who introduced ARB as an effective method to produce particulate MMCs.

Two-point incremental forming method is considered a modern technique for manufacturing shell parts. The presence of bottom punch during the process makes this technique far more complex than its conventional counterpart i.e. single-point incremental forming method. Thus, the numerical simulation of this method is an essential task, which leads to the reduction of trial/error costs, predicts the tearing of sheet and investigates various aspects of this complex method. Most of the previous works regarding numerical simulation of incremental forming method have concentrated on the single-point type of this technique. Moreover, all of these simulations have considered simple geometries like truncated cone, truncated hemisphere and truncated regular pyramid, which are based on well-known mathematical functions. In this study, a novel simplified procedure is presented for the finite element simulation of two-point incremental forming of free-form parts. The procedure is based on the extraction of tool-path points by using CAM software and the finite element model. In the current study, it will be shown how simulated results can be applicable for gaining useful information about the tearing of deforming sheets, selecting suitable numerical machines for practical forming processes and the deformation quality of sheets.

In this paper, the drawing process of multi-layer sheet metal through wedge shaped die has been analyzed using stream function and upper bound method. Typically a sandwich sheet contains three layers of metal, where the outer layers are of the same thickness and material and different from those of the inner layer. In this study, a new deformation model has been introduced in which inlet and outlet shear boundaries are considered flexible and the effect of work hardening of sheet layer materials has been considered. According to the suggested stream function, velocity field, strain rates and powers have been calculated. The optimized geometry of deformation zone and required drawing force has been determined depending on the process conditions. Analytical results, including drawing force and thickness of sheets in outlet of die have been compared with the finite element (FE) results. The FE results have a good agreement with the analytical results. Finally, the effects of friction factor and reduction in thickness have been investigated on the drawing force and the optimum die angle.

In the present article a numerical procedure is developed for dynamic analysis of single and double autofrettage of thick–walled FG cylinders under transient loading. The governing differential equations are discretized and presented in explicit Lagrangian formalism. The explicit transient solution of discrete equations are obtained on the meshed region and results for stress and strain distribution for relevant problems under inner and/or outer boundary conditions are established. The autofrettage behavior is subsequently analyzed through the application of time dependent pressure at boundary regions of the axisymmetric domain. Dynamic results, in particular in transient loading, are different in comparison with static ones due to the presence of plastic deformation and wave propagation. The residual stress resulting from internal pressure changes structural load bearing capacity of the cylinder in so far as the tensile stress of the outer layers might reduce while compressive stress of the inner layers increase. For functionally graded materials whose material properties change continuously, dynamic analysis yields results which are entirely different as compared with their static counterparts due to the change in wavelength and acoustic impedance. In the static analysis, the dimensionless forms of equations can be developed from the onset, while in the dynamic analysis the physical dimensions and material properties gain importance due to inherent properties of the stress waves. Residual stresses in the inner and outer parts of the cylinder are also studied for various volume fractions of FG material under single or double autofrettage.

Bone drilling process is one the most common processes in orthopedic surgeries and bone breakages treatment. It is also very frequent in dentistry and bone sampling operations. Bone is a complex material and the machining process itself is sensitive so bone drilling is one of the most important, common and sensitive processes in Biomedical Engineering field. Orthopedic surgeries can be improved using robotic bone drilling systems and mechatronic bone drilling tools. In the present study, multi-objective optimization is performed on the temperature and trust force at two steps. At the first step, two regression models are developed for modeling the temperature and force in bone drilling process considering three design variables namely tool’s rotational speed (V), feed rate (f) and tool diameter (D). At the second step, by using regression models, multi-objective genetic algorithm is used for Pareto based optimization of bone drilling process considering two conflicting objectives: temperature and force. It has been found out that there are considerable connections and feasible principles for an optimal design of the process in case of applying Pareto-based multi-objective optimization; otherwise these interesting results would not be discernible.

In the present study, parameters of tool rotation speed, tool travel speed and tool offsetting with different levels were used in the friction stir welding (FSW) of aluminum-copper tailor welded blanks (TWBs). The FSW of pure copper to 5052 aluminum alloy were carried out by varying tool rotation speed from 800 rpm to 1200 rpm, tool travel speed from 40 mm/min to 80 mm/min and tool offsetting from 1 mm to 2 mm. The L9 orthogonal array of Taguchi was used to design 9 experimental tests and each test was repeated three times. The uniaxial tensile test based on the ASTM-E8 was used for mechanical properties extraction of TWBs. The tool rotation speed of 1200 rpm, tool travel speed of 60 mm/min and tool offsetting of 1.5 mm resulted in the optimum range of heat input to form a stir zone with good quality. Using these FSW parameters caused the formation of thin intermetallic layers which stopped the motion of dislocation in the tensile test and resulted in higher tensile strength and joint quality. The scanning electron microscope (SEM) was used to scan the tensile fracture surface of TWBs.

In the tube drawing process, there are a bunch of parameters which play key role in process performance. Thus, finding the optimized parameters is a controversial issue. Current study aimed to produce a squared section of round tube by tube sinking process. To simulate the process finite element method (FEM) was used. Then, to find a meaningful kinship between process input and output parameters the developed FE model was associated with the design of experiment based response surface methodology (RSM). The sufficiency of each model was checked by analysis of variances. Further, the SA (simulated annealing) was associated with RSM models to find the optimal solution regarding maximum thickness distributions and minimum force and dimensional error. Hereafter, for performing accurate optimization, the principal component analysis was used to find the appropriate weight factor of each response. The obtained results were in right agreement with those derived from simulation and confirmatory experiment.