The imperialist Competitive Algorithm (ICA) is one of the recent meta-heuristic algorithms proposed to solve optimization problems. The Imperialist Competitive Algorithm is based on a socio-politically inspired optimization strategy. This paper presents an Imperialist Competitive Algorithm (ICA) to optimize the performance of a surface grinding operation. Moreover, the multi-objective optimization of a surface grinding process is suggested by using an evolutionary algorithm. Factors like depth of dressing, lead of dressing, workpiece speed and wheel speed are considered to minimize the production cost, surface roughness and to maximize the production rate. The suggested approach presents two constraints handling techniques: constraints handling strategy of ICA and penalty function method. The effectiveness of this algorithm for grinding operation is investigated by comparing the results to other algorithms available in the literature. Results show that the proposed algorithm in this work gives a better performance in a shorter time for the optimization of machining parameters in comparison to other works. تفاصيل المقالة

The joining of dissimilar metals by Friction stir welding (FSW) is one of the newest metal joining processes. In this research, the tool was made from H13 hot working steel, which has a concave shoulder with a 3-degree inclined angle. The welding operation performed using a milling machine. The non-homogeneous workpieces joining of the Al alloy (5083) and a sheet of annealed copper (ASTM B36) with a thickness of 2 mm was investigated by the FSW method. The joining process was carried out at three tool transverse speeds of 25, 35, and 45 mm per minute and three rotational velocities of 1000, 1300, and 1600 rpm. Microstructural changes of the welded samples were analyzed by optical microscopy and scanning electron microscopy used to distinguish the type of phases. While its mechanical properties analyze according to different parameters used in the experiments. Also, the welded parts were subjected to microhardness and tensile tests. It found that the welding sample with a tool rotational speed of 1,300 rpm and a forward speed of 35 mm/min has the best mechanical properties, with a tensile strength of 82% and a yield strength of 80% of aluminum base metal. While welded components with a forward speed of 25 mm/min have tunnel defects and brittle phases of AlCu and Al2Cu formed in the stir region so that with the increase of rotational speed and forward speeds, the percentage of these brittle phases increases. تفاصيل المقالة

Today, one of the new approaches of researchers to produce materials with very fine grains is the application of severe plastic deformation on the prototype with coarse grains. In this method, the grain size is reduced to the nanometer scale in several stages through applying strong strains to the sample, which leads to the improvement of mechanical and physical properties in the material. One of the most important methods of applying severe plastic deformation is the constrained groove pressing (CGP) process. According to studies, little research has been done on the weight loss of structures used in the military, maritime, aviation, and medical industries. Therefore, the mechanical behavior of the sheets was experimentally studied by the CGP method. The results show that the structure of 7075-T6 aluminum particles decreased in size from 60 microns to 270 nanometers by increasing the steps of this process. Also, the yield strength in the fourth pass increased by 38% compared to the annealed sample, and the tensile strength improved by 34%. In addition, the percentage of longitudinal increases in the fourth pass is reduced to its lowest value, ie 40%. تفاصيل المقالة

Over the last several decades, implants have been used to treat fractures and promote healing. The most important reason for deformation and shortening of the bone during healing due to loading on the nails is a lack of strength of the intramedullary nail. Materials with very fine grain dimensions are considered for such purposes. Ultrafine-grained (UFG) materials have structural elements with very fine grain sizes. Several methods for producing UFG materials have been developed, one of which is the top-down approach, which refines coarse-grained metals via severe plastic deformation (SPD). The SPD technique has several advantages that set it apart from other methods of synthesizing. Two of the SPD methods used in this study were the repetitive corrugation and straightening (RCS) process and the equal channel angular pressing (ECAP) process on a 316L stainless steel rod. Mechanical tests were performed on the rods produced using these methods. Under loading, simulation results revealed that the bone implanted by the RCS rod has greater structural stiffness than the bone implanted by an ECAPed 316L stainless steel rod. تفاصيل المقالة

The method of intramedullary nailing, which leads to the alignment of the diaphyseal broken bone, is one of the diaphyseal fractured bone healing novelties. The rods utilized must be strong enough to withstand the forces exerted by the transplanted bone. Today, various researchers are interested in using severe plastic deformation (SPD) methods to improve the mechanical characteristics of metals. One of the SPD procedures used in this study was repetitive corrugation and straightening (RCS) on a 316L stainless steel rod. After conducting mechanical characteristics tests on the rods produced using this approach, ABAQUS software was utilized to simulate the intramedullary nailing finite element method (FEM). The results of the experiments revealed that raising the number of pressing stages to eight significantly increases the hardness of the samples. The simulation findings revealed that the bone sample implanted by the rod manufactured by the aforementioned procedure has a higher structural hardness than the bone implanted by a basic 316L stainless steel rod under various stress conditions. تفاصيل المقالة