The Experts below are selected from a list of 10782 Experts worldwide ranked by ideXlab platform
Ken-ichiro Mori - One of the best experts on this subject based on the ideXlab platform.
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cold deep Drawing of commercial magnesium alloy sheets
Cirp Annals-manufacturing Technology, 2007Co-Authors: Ken-ichiro Mori, Hirokazu TsujiAbstract:A cold deep Drawing process for commercial AZ31 magnesium alloy sheets was developed. The commercial sheets were successfully formed into circular cups at room temperature by optimising the annealing temperature of the sheets, i.e. a limiting Drawing Ratio of 1.75 was attained for an annealing temperature of 500 °C. The increases in elongation, n-value and r-value, and the decrease in flow stress effective in the improvement of drawability were obtained for the annealing. The apparatus for cold deep Drawing without heating becomes much simpler than that for the conventional warm deep Drawing. The effects of the lubricant, the clearance between the die and the punch and the corner radius of the punch on the drawability were examined. The limiting Drawing Ratio was increased by applying force onto the edge of a blank through the die corner. In addition, cold deep Drawing of magnesium alloy square cups was performed. It was found that comparatively shallow magnesium alloy cups are satisfactorily formed at room temperature without heating.
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finite element analysis of the formability of an austenitic stainless steel sheet in warm deep Drawing
Journal of Materials Processing Technology, 2003Co-Authors: Hirohiko Takuda, Ken-ichiro Mori, T Masachika, E Yamazaki, Y. WatanabeAbstract:Abstract The forming limit in warm deep Drawing of a type 304 stainless steel sheet is experimentally examined and the deformation behaviour and the temperature change in the sheet are simulated by the combination of the rigid–plastic and the heat conduction finite element methods. In the simulation the deformation-induced martensitic transformation is taken into consideRation. The experimental and the numerical results show the positive effect of the heating on the drawability. The limiting Drawing Ratio becomes higher to 2.7 in the warm deep Drawing, while the Ratio is 2.0 at room temperature. The improvement in the drawability is attained by the comparatively low heating temperature under 150 °C and by the cooling of the punch. The forming limit and the necking site are successfully predicted by the simulation.
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optimisation of the distribution of wall thickness in the multistage sheet metal forming of wheel disks
Journal of Materials Processing Technology, 2002Co-Authors: Yohei Abe, Ken-ichiro Mori, O EbiharaAbstract:Abstract The distribution of wall thickness in the multistage sheet metal forming of wheel disks having a distribution of requisite strength was optimised in order to reduce the weight of the disks. Because high strength around the corner of the inner flat region of the formed disk is desirable, the decrease in wall thickness at the corner was minimised. The first two stages in which the wall thickness around the corner of the inner flat region in the final disk is determined were dealt with. Axisymmetric deformation in the two-stage forming process of disks is simulated by the rigid–plastic finite element method. The calculated distribution of the wall thickness after forming was in good agreement with the experimental results. The effects of the Drawing Ratio and the punch corner radius in the first stage, on the decrease in wall thickness at the inner corner after the second stage were examined by both finite element simulation and experiment. It was found that the Drawing Ratio and the punch corner radius in the first stage have optimal values for the decrease in wall thickness, respectively.
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finite element simulation of warm deep Drawing of aluminium alloy sheet when accounting for heat conduction
Journal of Materials Processing Technology, 2002Co-Authors: Hirohiko Takuda, Ken-ichiro Mori, I Masuda, M MatsuoAbstract:Abstract The deformation behaviour and the temperature change in cylindrical deep Drawing of an aluminium alloy sheet at elevated temperatures are simulated by the combination of the rigid-plastic and the heat conduction finite element methods. The comparison with the experimental results shows that the forming limits and the necking sites are successfully predicted by the simulation. It is clarified that the appropriate distribution of flow stress depending on temperature must exist in the sheet for the higher limiting Drawing Ratio. The numerical as well as the experimental results show that the limiting Drawing Ratio in the warm deep Drawing increases with the die profile radius.
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evaluation of limiting Drawing Ratio of laminated composite sheets by finite element simulation
Mechanical Behaviour of Materials VI#R##N#Proceedings of the Sixth International Conference Kyoto Japan 29 July℃2 August 1991, 1992Co-Authors: K. Yamaguchi, T Kawaguchi, T Goto, Ken-ichiro MoriAbstract:ABSTRACT To investigate the deformation characteristics of laminated composite sheet metals, the rigid-plastic finite element (FEM) simulation of axi-symmetric deep Drawing is carried out under various Drawing conditions. In the simulation, the normal anisotropy of each material constructing a composite sheet is taken into consideRation. The influences of the combination of materials and the thickness Ratio of composite sheets on the limiting Drawing Ratio (LDR), thickness strain distribution and Drawing load are examined. It is shown that for aluminum-steel two layer sheets, the LDR increases with increasing thickness of the steel sheet. For a given thickness Ratio, the LDR of the laminated composite blank becomes larger when the steel side of the blank contacts punch. This is qualitatively consistent with experimental results.
Daw-kwei Leu - One of the best experts on this subject based on the ideXlab platform.
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a simplified approach to estimate limiting Drawing Ratio and maximum Drawing load in cup Drawing
Journal of Engineering Materials and Technology-transactions of The Asme, 2004Co-Authors: Daw-kwei LeuAbstract:A new and practically applicable equation, including the normal anisotropy R, the strain hardening exponent n, the friction coefficient μ, and the bending factor t 0 /r d for estimating the limiting Drawing Ratio LDR (a measure of drawability of sheet metal) in cup Drawing of a cylindrical cup with a flat-nosed punch is derived by an elementary theory of plasticity in an explicit form. Whiteley's and Leu's equations for estimating the LDR, and Hill's upper limit value of LDR, all are the special cases of the derived equation. The estimation of LDR agrees well with the experiment. It is shown that the most important parameters for LDR are the normal anisotropy R and friction coefficient μ, however the strain hardening exponent n has little effect on the LDR. On the other hand, a new and simple equation, incorporating the derived LDR and the critical Drawing load Pc, for estimating the maximum Drawing load Pd at a certain Drawing Ratio is derived. It also agrees well with the experiment. It is thereby possible to better understand and control the Drawing limit of sheet metal in industry necessity.
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The limiting Drawing Ratio for plastic instability of the cup-Drawing process
Journal of Materials Processing Technology, 1999Co-Authors: Daw-kwei LeuAbstract:Abstract The plastic instability of cup-Drawing is usually measured by the limiting Drawing Ratio (LDR). A new and practically applicable equation for estimating the LDR in the cup-Drawing of a cylindrical cup with a flat-nosed punch is derived using an integral technique based on the load-maximum principle for localization of the plastic flow. It is a function of the process parameters of normal anisotropy value R , strain-hardening exponent n , friction coefficient μ , radius of the die arc r d , half die opening r 1 and yield strength σ y , and can clearly explore the interaction between the process parameters and the LDR in a theoretical manner. Good agreement between calculation and experiment is obtained. It is thereby possible to better understand and control cup-Drawing behavior for optimum press-drawability.
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prediction of the limiting Drawing Ratio and the maximum Drawing load in cup Drawing
International Journal of Machine Tools & Manufacture, 1997Co-Authors: Daw-kwei LeuAbstract:Abstract A new, simple and practically applicable equation, including the normal anisotropy value R and the strain hardening exponent n, for estimating the limiting Drawing Ratio LDR in cup-Drawing of a cylindrical cup with a flat-nosed punch is derived. The normal anisotropy is based on Hill's theory of an anisotropy sheet that is isotropic in its plane. Whiteley's equation for estimating the LDR, and Hill's upper limit value of LDR, are two special cases of the new equation. Compared with the published experimental work, good agreement between the calculation and the experiment is obtained. The new equation shows that the most important parameter for LDR is the normal anisotropy value R, the strain hardening exponent n has also some influence on the LDR, and clearly explains the real interaction between the normal anisotropy value R and the strain hardening exponent n on the LDR. It is different from other equations, which are functions of the normal anisotropy value R only. A new equation, incorporating the value of LDR derived as above and the critical Drawing load Pc based on the maximum load principle for localization of plastic flow, for estimating the maximum Drawing load Pc at a certain Drawing Ratio DR in cup-Drawing with a flat-nosed punch is developed. This equation is simple and supplies an accurate estimation of the maximum Drawing load Pd. A comparison between the calculation and the experiment shows that good agreement is also obtained. It is thereby possible to better understand and control the cup-Drawing behavior of sheet metal.
Zhrgang Wang - One of the best experts on this subject based on the ideXlab platform.
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deep Drawing of magnesium alloy sheets at warm temperatures
Journal of Materials Processing Technology, 2007Co-Authors: Shuqua Zhang, Ku Zhang, Zhongtang Wang, Zhrgang WangAbstract:Abstract In magnesium alloy sheet products have been attracting more and more attention in recent years because of their application potentials as coverings of portable electrical devices and automotive panels. However, magnesium alloy sheets are usually formed at temperatures between 250 and 400 °C because of their poor plasticity at room temperature, which makes the tooling system quite complex and also the products cost expensive. A proper forming temperature range was determined. The effects of blank holding forces on the workpiece quality were analyzed by warm deep Drawing of cups from magnesium alloy sheets. Therefore, appropriate process parameters were selected to avoid forming defects effectively. In the paper, a rigid blank holder was used to adjust blank holding forces. A special liquid lubricant PTFE was used on the tool surfaces. The conditions of process defects as flange wrinkling and ruptures were analyzed. Experiments were carried out to verify the computer simulation results. Efforts were made to optimize process parameters by analyzing the causes of defects in order to improve the Limit Drawing Ratio of magnesium alloy workpieces. Computer simulation with explicit finite element method was used to optimize the process parameters before carrying out the actual experiments. It is found that rolled magnesium alloy sheets have good deep Drawing formability at a forming temperature range of 105–170 °C with the limit Drawing Ratio up to 2.6. It is also necessary to control the time of heating blanks. The formability will be reduced severely by excessive heating duRation.
Hirohiko Takuda - One of the best experts on this subject based on the ideXlab platform.
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finite element analysis of the formability of an austenitic stainless steel sheet in warm deep Drawing
Journal of Materials Processing Technology, 2003Co-Authors: Hirohiko Takuda, Ken-ichiro Mori, T Masachika, E Yamazaki, Y. WatanabeAbstract:Abstract The forming limit in warm deep Drawing of a type 304 stainless steel sheet is experimentally examined and the deformation behaviour and the temperature change in the sheet are simulated by the combination of the rigid–plastic and the heat conduction finite element methods. In the simulation the deformation-induced martensitic transformation is taken into consideRation. The experimental and the numerical results show the positive effect of the heating on the drawability. The limiting Drawing Ratio becomes higher to 2.7 in the warm deep Drawing, while the Ratio is 2.0 at room temperature. The improvement in the drawability is attained by the comparatively low heating temperature under 150 °C and by the cooling of the punch. The forming limit and the necking site are successfully predicted by the simulation.
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finite element simulation of warm deep Drawing of aluminium alloy sheet when accounting for heat conduction
Journal of Materials Processing Technology, 2002Co-Authors: Hirohiko Takuda, Ken-ichiro Mori, I Masuda, M MatsuoAbstract:Abstract The deformation behaviour and the temperature change in cylindrical deep Drawing of an aluminium alloy sheet at elevated temperatures are simulated by the combination of the rigid-plastic and the heat conduction finite element methods. The comparison with the experimental results shows that the forming limits and the necking sites are successfully predicted by the simulation. It is clarified that the appropriate distribution of flow stress depending on temperature must exist in the sheet for the higher limiting Drawing Ratio. The numerical as well as the experimental results show that the limiting Drawing Ratio in the warm deep Drawing increases with the die profile radius.
K. Yamaguchi - One of the best experts on this subject based on the ideXlab platform.
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friction aided deep Drawing of sheet metals using polyurethane ring and auxiliary metal punch part 1 experimental observations on the deep Drawing of aluminium thin sheets and foils
International Journal of Machine Tools & Manufacture, 2002Co-Authors: M A Hassan, N Takakura, K. YamaguchiAbstract:Abstract Friction aided deep Drawing based on the Maslennikov process is investigated as a method to facilitate the deep Drawing of sheet metals with poor drawability. Aluminium foils and thin sheets of 0.1–0.4 mm in thickness are used as a model for the material with poor drawability. An auxiliary metal punch is used together with a polyurethane ring to increase the Drawing efficiency and to improve the dimensional accuracy of the drawn cup. The effect of Drawing conditions such as thickness, hole diameter and the hardness of the polyurethane ring on the cup height are mainly investigated. Also, the optimum number of Drawing opeRations required to achieve a given Drawing Ratio is examined by repeating compression and unloading the polyurethane ring. The experimental results show that even for foil and thin sheets, deep cups with Drawing Ratios of 2.25 and with good shape and dimensional accuracy can be obtained by repeating the Drawing opeRation about ten times. The achievable Drawing Ratio is appreciably larger when compared with that obtained by the conventional deep Drawing process.
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increase in limiting Drawing Ratio by using partially thickened blanks
International Journal of Machine Tools & Manufacture, 1993Co-Authors: M H Parsa, K. Yamaguchi, Norio TakakuraAbstract:Abstract Deep Drawing of a partially thickened blank, the thickness of which is somewhat larger at the punch head portion than at the flange portion, is investigated in an attempt to increase the limiting Drawing Ratio (LDR). A rigid-plastic finite element simulation is firstly used to predict the effect of the partially thickened blank on the increase in LDR. To confirm the result of the simulation, deep Drawing experiments are carried out using partially thickened blanks that are produced by machining. In addition, spot welding and forging process methods are employed to produce partially thickened blanks. The finite elements simulation and experimental results show that when a partially thickened blank is used, the LDR increases appreciably compared with that for a normal blank of uniform thickness.
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evaluation of limiting Drawing Ratio of laminated composite sheets by finite element simulation
Mechanical Behaviour of Materials VI#R##N#Proceedings of the Sixth International Conference Kyoto Japan 29 July℃2 August 1991, 1992Co-Authors: K. Yamaguchi, T Kawaguchi, T Goto, Ken-ichiro MoriAbstract:ABSTRACT To investigate the deformation characteristics of laminated composite sheet metals, the rigid-plastic finite element (FEM) simulation of axi-symmetric deep Drawing is carried out under various Drawing conditions. In the simulation, the normal anisotropy of each material constructing a composite sheet is taken into consideRation. The influences of the combination of materials and the thickness Ratio of composite sheets on the limiting Drawing Ratio (LDR), thickness strain distribution and Drawing load are examined. It is shown that for aluminum-steel two layer sheets, the LDR increases with increasing thickness of the steel sheet. For a given thickness Ratio, the LDR of the laminated composite blank becomes larger when the steel side of the blank contacts punch. This is qualitatively consistent with experimental results.
