Ghader Faraji; Mohammad Kazem Besharati Givi; Saeed Yarmohammadi; Mahmoud Mousavi Mashhadi
Abstract
Deep drawing of cylindrical shapes with high limiting drawing ratio (LDR) values is relatively difficult. Annealing is a further operation, which in turn adds costs and consumes significantly time to the forming process. In the present work, cylindrical cups from brass sheet were made with only limited ...
Read More
Deep drawing of cylindrical shapes with high limiting drawing ratio (LDR) values is relatively difficult. Annealing is a further operation, which in turn adds costs and consumes significantly time to the forming process. In the present work, cylindrical cups from brass sheet were made with only limited anneal during few steps, but having LDR of 9 that is about 2 times higher than previous works. Cups having 4 mm IDs and 70 mm heights were made successfully. The process was simulated by ABAQUS/Explicit finite element (FE) code and experimental tests were carried out based on FEM results. Parameters affecting the process were studied with experimental results, as well as FEM. The wall thickness obtained from the approach were compared for several tests, and verified significantly.
Amin Samadi Ghoushchi; Caren Abrinia; Mohammad Kazem Besharati Givi
Abstract
Slab method of analysis has been used for solving metal forming problems for a long time. However it has been restricted to plane strain and axisymmetric problems due to limitations in its formulations. In this paper a new formulation has been proposed so that it could be applied to three dimensional ...
Read More
Slab method of analysis has been used for solving metal forming problems for a long time. However it has been restricted to plane strain and axisymmetric problems due to limitations in its formulations. In this paper a new formulation has been proposed so that it could be applied to three dimensional problems in metal forming. A parametric slab has been considered in this analysis and the force balance on the slab was carried to obtain equilibrium equations in terms of these parameters. The parameters in fact are related to the geometry of the final extruded shape, the die and the material flow regime assumed in the formulation. In this way most of the limitations encountered in previous formulations were surpassed. The effect of reduction of area, frictional conditions and other process parameters on the extrusion pressure was investigated. The theoretical results obtained in this paper were compared with the results of finite element method and a good agreement was observed between them.
Mohammad Kazem Besharati Givi; Mehdi Ghasemi; Seyyed Mahmoud Mousavi Mashhadi
Abstract
In this paper a special sandwich panel with a sinusoidal core under distributed load on upper and lower plates has been studied. By drawing free body diagrams, and using energy method and Castagiliano theory the forces and moments involved in the core has been determined. Then, the stresses, normal and ...
Read More
In this paper a special sandwich panel with a sinusoidal core under distributed load on upper and lower plates has been studied. By drawing free body diagrams, and using energy method and Castagiliano theory the forces and moments involved in the core has been determined. Then, the stresses, normal and horizontal displacements due to above forces and moments are calculated. In order to ensure the accuracy of the analysis, the results obtained are verified by using ANSYS software. Finally, by use of displacement as a constraint for sandwich panel, optimization is carried out for this problem by genetic algorithm and MOEA toolbox in MATLAB environment. The results obtained from optimization and other analysis show a very good agreement.
Mohammad Kazem Besharati Givi; Amir Sarvari
Abstract
In all engineering applications where solid surfaces slide on each other, friction plays an important role. It becomes even more important, particularly in metal forming processes where the two sliding materials are metallic. Among forming processes, forging is an important process, because of improving ...
Read More
In all engineering applications where solid surfaces slide on each other, friction plays an important role. It becomes even more important, particularly in metal forming processes where the two sliding materials are metallic. Among forming processes, forging is an important process, because of improving material structure, mechanical properties and reducing production time. An inverse analysis technique has been developed to determine the flow stress and friction at the tool/work piece interface simultaneously. The inverse problem is aimed at minimizing the error between experimental data and predictions made by rigid-plastic simulations. The ring compression test was selected for evaluating the method for bulk forming of Aluminum7075. The determined friction data were compared with corresponding data obtained independently using standard calibration curves for cold forging in the ring compression test. Results show that the method discussed in the study is efficient and accurate.
Mohammad Kazem Besharati Givi; Akbar Afaghi Khatibi; Mansour Akbari
Abstract
Evidence from the early and late industrializes shows that technology, as the commercial application of scientific knowledge, has been a major driver of industrial and economic development. International technology transfer is now being recognized as having played an important role in the development ...
Read More
Evidence from the early and late industrializes shows that technology, as the commercial application of scientific knowledge, has been a major driver of industrial and economic development. International technology transfer is now being recognized as having played an important role in the development of the most successful late industrializes of the second half of the 20th Century. Our society stands to be significantly influenced by carbon nanotubes, shaped by nanotube applications in every aspect, just as silicon-based technology still shapes society today. Nanotubes can be formed in various structures using several different processing methods. In this paper, the synthesis methods used to produce nanotubes in industrial or laboratory scales are discussed and a comparison is made. A technical feasibility study is conducted by using the multi criteria decision-making model, namely Analytic Hierarchy Process (AHP). The article ends with a discussion of selecting the best method of Technology Transferring of Carbon Nanotubes to Iran.
