Готові списки джерел за темами / BLANK HOLDING FORCE

Добірка наукової літератури з теми "BLANK HOLDING FORCE"

Автор: Grafiati

Опубліковано: 11 вересня 2023

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Статті в журналах з теми "BLANK HOLDING FORCE"

Thiruvarudchelvan, S., and W. G. Lewis. "Deep Drawing With Blank Holder Force Approximately Proportional to the Punch Force." Journal of Engineering for Industry 112, no. 3 (August 1, 1990): 278–85. http://dx.doi.org/10.1115/1.2899587.

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A new method of applying blank holding force approximately proportional to the punch force in cup drawing is presented. An annular urethane pad compressed between two parts of a punch expands and applies pressure against the tubular part of a blank holder. As the punch moves to draw the blank, friction between the urethane pad and the blank holder applies automatically a blank holding force approximately proportional to the punch force. Experimental investigations were carried out with aluminum blanks to determine the optimum conditions to obtain wrinkle-free cups. Variations of the punch force and the blank holding force with punch stroke for aluminum blanks under different degrees of wrinkling are presented. Strains on the cup wall measured with this method are presented and compared with those obtained under constant blank holding force conditions. Theoretical critical blank holding pressure variation with punch stroke is compared with the pressure variation that obtains with the present method. Using the deep drawing theory an expression to predict the punch force with this method is also presented.

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Shan, Ti Kun, and Li Liu. "Springback of TRIP Steels under Varying Blank Holder Force." Key Engineering Materials 561 (July 2013): 620–25. http://dx.doi.org/10.4028/www.scientific.net/kem.561.620.

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The method using variable blank holding force to control springback in drawing of TRIP sheet steel is discussed. Numerical simulations considering the variation of Youngs modulus of TRIP steels can improve springback simulation accuracy. Many experiments are use to test and the accuracy of the springback simulation for an U-channel part forming under variable blank holding force. The results shows that the strategy of variable blank holding force is an effective measure for the springback control in TRIP sheet metal forming processes and the dimensional accuracy of sheet metal parts can be increased by the optimization of variable blank holding forces

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Tan, Chin Joo, and Afshin Aslian. "FE simulation study of deep drawing process of SUS304 cups having no delayed cracks under enhanced blank holding force." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 234, no. 1-2 (June 15, 2019): 84–94. http://dx.doi.org/10.1177/0954405419855230.

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In the experiment, delayed cracks in deep drawing processes of metastable stainless steel SUS304 cylindrical cups were prevented using elevated blank holding force aided by nanolubrication. Besides tensile residual hoop stresses, the elimination of the cracks was also attributed to the change in wall thickening profile along the wavy cup edges. The wall thickening is a result of the high circumferential stress acting in the flange, leading to the high concentration of deformation-induced martensite and high risk of cracks. The amount of increase in wall thickness in the valleys along the edge during the deep drawing process was higher than the peaks at low blank holding force range due to shorter heights. Therefore, the portions of blank equivalent to the valleys were subject to higher holding force during the process, resulting in decrease in degree of wall thickening with increase in height for blank holding force up to 25 kN. However, the wall thickening and the height increased at blank holding force of 28 kN due to the same amount of increase in wall thickness in both valleys and peaks, resulting in a larger contacting area and lower holding force. Therefore, the wall thickness in the valleys sharply increased, and the formation of the cracks persists. Within the crack-free range, that is, from 29 to 31 kN, both the heights and wall thickening decreased. The decrease in frictional force by means of the nanolubrication has facilitated the flow of material into the die, resulting in lower cup height. It also facilitated the flow of materials away from the thick valley regions under the high pressure, resulting in significant decrease in degree of wall thickening. The cracks were prevented. The amount of compression at blank holding force of 32 kN was insufficient to suppress the increase in wall thickening in valleys, resulting in the formation of the cracks again.

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He, Sijun, Xin Wu, and S. Jack Hu. "Formability Enhancement for Tailor-Welded Blanks Using Blank Holding Force Control." Journal of Manufacturing Science and Engineering 125, no. 3 (July 23, 2003): 461–67. http://dx.doi.org/10.1115/1.1580853.

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Tailor-welded blanks (TWB) are widely used for stamped auto body panels because of their great benefits in weight and cost reduction. However, the weld line in a tailor-welded blank causes serious concerns in formability because of material discontinuity and additional inhomogeneous stress/strain distribution. This paper proposes a blank holding force (BHF) control strategy to control the weld line movement, distribute the deformation more uniformly and thereby improve TWB formability. The control methodology is developed based on a simplified 2-D sectional analytical model that estimates the stress/strain distribution and the BHFs required for each side of the flange with dissimilar materials. The model can be further extended to 3-D analysis by superimposing the 2-D sectional analysis results around the entire binder ring and thus determining the required BHF for the whole panel. Finite element simulations are performed to study the effects of forming parameters on the weld line movement. Experiments have been conducted to verify the analytical model and partial finite element simulations. Both analysis and experiments demonstrated that a lower BHF should be applied on the thicker blank side to allow more metal to flow-in for obtaining more uniform strain distribution. The proposed BHF control is proven to be a good approach to enhancing TWB formability.

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Qian, Jian Qing, Ji Ping Chen, and Hai Fan Qian. "The Influence of N Values on Sheet Metal Deep Drawing Based on Different Blank Holder Forces." Advanced Materials Research 418-420 (December 2011): 1364–67. http://dx.doi.org/10.4028/www.scientific.net/amr.418-420.1364.

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The influence of hardening index n value at different holding forces on LDR of cylinder cup was simulated by the finite element software PAM-STAMP 2G. The results showed that the limit drawing ratio of the sheet metal decreased with the increase of the blank holder force. There was little influence of hardening index n value on the limit drawing ratio at smaller blank holder force. The influence of hardening index n value on the limit drawing ratio increased with the increase of the blank holder force. The hardening index n value could be increased to increase the limit drawing ratio when the blank holder force is large.

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Ke, Jun Yi, Yu Qi Liu, Gui Li, and Ting Du. "Springback Experimental Research of Advanced High-Strength Steel." Advanced Materials Research 842 (November 2013): 284–88. http://dx.doi.org/10.4028/www.scientific.net/amr.842.284.

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Springback is one of the major problems of high strength steel.Based on the NUMISHEET’96 S_Rail standard examination questions,using the characteristics of the servo press 200T,the blank holder force,different pressure holding time and the holding times of advanced high strength steel DP280-440, DP340-590, DP400-780 are studied. By changing one of the three impact factors ,three group experiments are carried out.The experimental results show that the springback can change evidently with the increasing of the blank holder force and the holding times,but the holding time has little influence on the springback.What’s more,the springback angle of DP400-780 is the biggest ,proving the higher the yield stress,the bigger the springback angle.Therefore, in the stamping of advanced high strength steel, increasing the blank holder force and holding times are effective methods to solve the springback.

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Yoon, Hyung Sop, Sergei Alexandrov, Kwan Soo Chung, Robert E. Dick, and T. J. Kang. "Prediction of Critical Blank-Holding Force Criterion to Prevent Wrinkles in Axi-Symmetric Cup Drawing." Materials Science Forum 505-507 (January 2006): 1273–78. http://dx.doi.org/10.4028/www.scientific.net/msf.505-507.1273.

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The repression of wrinkling during sheet metal forming has been a significant issue in recent years. In order to provide a reliable and efficient tool to predict the critical blank holding force to prevent wrinkles, an axi-symmetric analytical model for flange wrinkling is introduced here. Using a conventional theory of the critical condition, the critical blank-holding force and wave numbers are numerically predicted. Comparison between the numerical and experimental results shows excellent agreement for various blank dimensions and materials.

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Venkateshwar Reddy, P., S. Hari Prasad, Perumalla Janaki Ramulu, Sirish Battacharya, and Daya Sindhu Guptha. "Effect of Geometries of Die/Blank Holder and Punch Radii in Angular Deep-Drawing Dies on DP Steel Formability." Applied Mechanics and Materials 813-814 (November 2015): 269–73. http://dx.doi.org/10.4028/www.scientific.net/amm.813-814.269.

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In recent days deep-drawing is one of the most important methods used for sheet metal forming. The geometries of die/blank holder and punch are one of the parameters for deep-drawing. This paper presents an attempt to determine the effect of different geometries of die/blank holder, punch radii and blank holding force on deep drawing process for the formability of DP Steel of 1mm sheet. The numerical simulations are performed for deep drawing of cylindrical cups at a constant frictional coefficient of 0.12 and different blank holding forces of 10, 15 and 20kN are used. For numerical simulation PAM STAMP 2G a commercial FEM code in which Hollomon’s power law and Hills 1948 yield’s criterion is used. The die/blank holder profile used with an angles of α=0°, 12.5°, 15° and die/punch profile with a radii of R= 6 and 8mm were simulated to determine the influence of punch force and thickness distribution on the limit drawing ratio. The aim of this study is to investigate the effect of tool geometries on drawability of the deep-drawing process.

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Seo, Hyung Yoon, Chul Kyu Jin, and Chung Gil Kang. "Effect on Blank Holding Force on Blank Deformation at Direct and Indirect Hot Deep Drawings of Boron Steel Sheets." Metals 8, no. 8 (July 25, 2018): 574. http://dx.doi.org/10.3390/met8080574.

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This study involves performing direct and indirect hot press forming on ultra-high-strength steel (UHSS) boron steel sheets to determine formability. The indirect hot press process is performed as a cold deep drawing process, while the direct hot press process is performed as a hot deep drawing process. The initial blank temperature and the blank holding force are set as parameters to evaluate the performance of the direct and indirect deep drawing processes. The values of punch load and forming depth curve were obtained in the experiment. In addition, the hardness and microstructure of the boron steel sheets are examined to evaluate the mechanical properties of the material. The forming depth, maximum punch load, thickness, and thinning rate according to blank holding force were examined. The result shows that a larger blank holding force has a more significant effect on the variation of the thickness and thinning rate of the samples during the drawing process. Furthermore, the thinning rate of the deep drawing part in with and without fracture boundary was respectively examined.

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Wang, Guang Kai, Si Yuan Cheng, Su Yang Li, and Xiang Wei Zhang. "Application of Numerical Simulation in Stamping Process of Complex Box-Type Parts." Advanced Materials Research 291-294 (July 2011): 579–84. http://dx.doi.org/10.4028/www.scientific.net/amr.291-294.579.

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Due to the recent development both in the numerical simulation technology and computer technology, the role of numerical simulation in sheet forming industry has been continuously increasing in recent years. This paper describes the application of numerical simulation technology in the forming process of a complex box-type part with Dynaform and gives a fairly accurate forecast of defects that may appear in the forming process. Prediction of the effect of design parameters such as blank holding force and drawbeads on forming quality is investigated. The study indicates that blank holding force and drawbead directly affect the metal flow and formability of stamping. Then, by adjusting blank holding force and setting appropriate drawbeads, an optimized stamping process plan is obtained and is validated in experiments. Finally the phenomenon and displacement of distortion springback are predicted in the springback simulation, which is useful to further improve the quality of this kind of part.

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Дисертації з теми "BLANK HOLDING FORCE"

Chen, Chien-Tsu, and 陳建志. "Finite Element Analysis of the Blank Holding Force Control andFormability in Deep Drawing Process." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/31426419197306470468.

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碩士
國立雲林科技大學
機械工程系碩士班
89
The two most common defects encountered in sheet metal forming are the tearing and wrinkling of workpiece. An excessively high force imposed by the blank holder will induce tearing on the side-wall while an insufficient holding force will cause wrinkling in the flange area. A holding force that varies with the punch stroke is therefore to suggested to effectively delay or prevent the product from failures, by predicting the onset of tearing or wrinkling and adjusting the holding force based an adequate algorithm. In this thesis, three modes of holding force control are proposed: mode of force-difference, mode of force-ratio, and the mode of pulsating-force. All the control modes are integrated with the explicit non-linear finite element code, LS-DYNA, in the simulation of the deep drawing of square cups. The numerical results regarding the evaluation of product quality, such as the uniformity of wall thickness and the height of wrinkling in the flange are observed. It is found that both the modes of force-difference and force-ratio can successfully suppress the occurrence of tearing and wrinkling. However, though being a much simpler controlling method, the pulsating-force mode shows different optimum frequency and amplitude of the force pulsation, according to the objective of force control, say, the uniformity of thickness, the formability of cup height, or the minimum spring —back of cup wall.

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Yang, Tzyy-Chang, and 楊梓群. "A Study on the Servo Control of Blank Holding Force in Sheet Metal Forming Processes." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/45467929469139158452.

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碩士
國立雲林科技大學
機械工程技術研究所
88
During sheet metal forming process, an appropriate clamping force is usually needed in order to effectively suppress wrinkles caused by circumferential force on the blank. An excessively high blank holding force (BHF) will generally incur cup wall tearing, whereas too low a BHF is not capable of preventing wrinkles. An ideal BHF should be variable, it should be reduced when the wall thickness is below safety, and be elevated when wrinkles occur. In this study, a newly developed photoelectric displacement sensor (PDS) was used to directly measure the displacement on shoulder corner of the die. The change in wall thickness was calculated which then serve as a controlling parameter of wall tearing. Another PDS was placed on flange area to measure the height of the flange. The change in flange height was also calculated as a controlling parameter of wrinkles. A hydraulic PID servo controller in a microcomputer was used to control pressure output. The displacement measured in PDS was process by PID controller, which then feedback to a proportional hydraulic valve. A suitable real-time clamping force was applied according to the control criteria. In order to effectively prevent flange wrinkles and wall tearing during sheet metal forming process, appropriate criteria are needed to timely control holding force, so that a fluent plastic flow between punch and die as well as better forming depth are acquired. In this thesis, two sets of criteria are developed, namely, the criteria of tearing thickness and the tearing-wrinkle controlling criteria. The influences of these criteria on correcting parameters and the initial clamping area are also discussed. The terminal goal of this study is to reach an optimized forming height and cup wall thickness, to effectively control formability of sheet metal, and to reduce the cost as well as time during design and manufacturing processes.

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KUMAR, SUNIL. "SELECTION OF MATERIAL FOR DEEP DRAWING OF A FUEL TANK AND ITS FINITE ELEMENT SIMULATION." Thesis, 2017. http://dspace.dtu.ac.in:8080/jspui/handle/repository/15902.

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Deep drawing is a sheet metal forming process in which deformation forces are oriented in the plane of the sheet, and the surface pressures in the tool are generally lower than the yield stress of the sheet material. The limits of the sheet metal forming are determined by the occurrence of defects such as wrinkling and tearing on the blank which are the most frequent types of failure. The present work discusses the numerical investigations of deep drawing of a cold rolled draw quality steel and interstitial free steel blank of 0.8mm and 1.2mm thickness in to a shape of a fuel tank with varying blank holding forces. The tensile specimens are laser cut from a blank with known rolling direction as per ASTM E8M standard and are tested for tensile properties and anisotropy. These properties were used in the material model in FE analysis of the process using HYPERWORKS. It is observed numerically that optimum blank holder force is necessary to remove the wrinkling defects. Deep drawing parameters like percentage thinning and plastic strain along with respective forming limit diagrams have been obtained for individual cases and thus changes in these parameters with varying thickness and material is area of investigation for understanding deep drawing process over fuel tank.

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Книги з теми "BLANK HOLDING FORCE"

The Effect of Interface Friction in Drawing AISI 304 Stainless Steel and AL1100 Materials at Constant Blank Holding Force using on Finite Element Simulation Studies. Tiruchengode, India: ASDF International, 2017.

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Board Jr., Marcus. Invisible Weapons. Oxford University PressNew York, 2022. http://dx.doi.org/10.1093/oso/9780197605226.001.0001.

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Abstract This book explains how grassroots communities are infiltrated and politically co-opted in ways that render their resistance harmless. It reveals contemporary practices of domination, as power-holding elites—from elected officials to welfare bureaucrats—are teaching oppressed people to internalize their grievances and silence their needs. In the end, politics becomes a space where advocating for social justice makes less and less sense to people. The book therefore explains the politics of radical inaction through disempowerment, dissonance, and disengagement. It considers multiple sites of resistance to police violence, including the police killing of Akai Gurley, Freddie Gray, and Korryn Gaines in particular. It also considers the mass protest associated with the wider Movement for Black Lives (M4BL). The book argues that anti-radicalism is an embedded feature of neoliberalism, that the widespread adoption of neoliberal politics has reinforced ongoing racial and gender oppressions, and that these same oppressed communities are being infiltrated in order to minimize their commitments to radical political resistance. Covering multiple sites and methods—from in-depth interviews on the resistance politics of Black welfare recipients in Chicago, to nationally representative survey data on hard-work beliefs in politics and the labor force, and case study analyses of police violence in Baltimore and New York—the book shows how political domination today is about ensnaring minds, constraining imaginations, and upending resistance. With the creation of the invisible weapons framework, future research can better explain sites of political disengagement and the connection to the erosion of whatever remains of democracy in the United States.

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Частини книг з теми "BLANK HOLDING FORCE"

Yoon, Hyung Sop, Sergei Alexandrov, Kwan Soo Chung, Robert E. Dick, and T. J. Kang. "Prediction of Critical Blank-Holding Force Criterion to Prevent Wrinkles in Axi-Symmetric Cup Drawing." In Materials Science Forum, 1273–78. Stafa: Trans Tech Publications Ltd., 2006. http://dx.doi.org/10.4028/0-87849-990-3.1273.

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Manabe, K., H. Nishimura, and H. Hamano. "An Improvement in Deep Drawability of Steel/Plastic Laminate Sheets by Control of Blank Holding Force." In Advanced Technology of Plasticity 1987, 1297–304. Berlin, Heidelberg: Springer Berlin Heidelberg, 1987. http://dx.doi.org/10.1007/978-3-662-11046-1_78.

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Siraji, Amirela, Tsegaye Bekele, Perumalla Janaki Ramulu, Habtamu Beri, and P. Venkateswar Reddy. "Investigation of the Effect of Blank Holding Force on Earing Defect During Circular Deep Drawing Process Through Finite Element Analysis and Experimentation Using AA6061 and Low-Carbon Steel Sheets." In The Minerals, Metals & Materials Series, 219–29. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-06212-4_20.

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Pugh, Jonathan, and David Chandler. "Storiation: Holding the World." In Anthropocene Islands: Entangled Worlds, 141–78. University of Westminster Press, 2021. http://dx.doi.org/10.16997/book52.e.

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In Chapter 5, the authors give shape to an approach called Storiation. Central to Storiation is registering the ongoing afterlives, hauntings and effects of such significant forces as colonialism, modernity, global warming, nuclear radiation, rising sea levels, and waste production; where islands and island cultures regularly emerge as important sites for investigation. What distinguishes the Storiation analytic is the holding together of entities and effects, registered through islands and islander lives, intra-actions and effects. For authors like Timothy Morton the (island) future then becomes entangled with the past as the ‘afterlife’ of relational effects continue to reverberate in ‘strange’, ‘weird’ or ‘quantum’ ways. The chapter examines how the analytic of Storiation is today being widely developed in Anthropocene philosophy, critical Black and Indigenous Studies which all increasing turn to engage islands as key sites of relational entanglements and associated island scholars and literatures. Of particular importance is the work of the Barbadian writer Kamau Brathwaite. Brathwaite’s onto-epistemology of ‘tidalectics’ profoundly disrupts mainland, continental and modern frameworks of space-time, and binaries of human/nature. In Tiffany Lethabo King’s Storiations of Black and Indigenous life, she employs such methods as ‘critical fabulation’ and ‘speculative bricolage’ in order to hold together the traces, ghosts and afterlives of colonialism embodied and constitutive of the present. Thus, the chapter charts Storiations of the differentiating powers of colonialism, of the emergence of tidalectic psychologies living on in the wake, of island dances, Vodou loa and shamanistic practices, of species long extinct, of the consumerisms that haunt islands in strange ways.

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Jackson, Alicia K. "Promised Land." In The Recovered Life of Isaac Anderson, 114–29. University Press of Mississippi, 2021. http://dx.doi.org/10.14325/mississippi/9781496835147.003.0008.

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As a large number of Black Georgians leave the state, white leaders attempt to dissuade them from leaving. Isaac Anderson is forced to leave Georgia under the threat of imprisonment, and not long after leaving, he loses his wife, Edith, and for several years, disappears from the public record as he takes refuge in Arkansas. The promise of a better life in Arkansas is short lived however, and Anderson moves to North Mississippi where he returns to ministry in Sardis in Panola County and in Holly Springs in Marshall County where Blacks are experiencing greater economic opportunity, holding political office, and forming their own churches and educational institutions with Blacks in leadership roles.

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Hess, Earl J. "They Are upon Us." In Storming Vicksburg, 1–14. University of North Carolina Press, 2020. http://dx.doi.org/10.5149/northcarolina/9781469660172.003.0001.

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On May 17, after his army was defeated at the Battle of the Big Black River, Confederate General John C. Pemberton ordered a retreat back to the city of Vicksburg. He had just been humiliated by Union General Ulysses S. Grant, who, through rapid marching, staying one step ahead of his adversary, had defeated Confederate forces in four pitched battles. The Federals had captured sixty-five pieces of artillery, took out of action 14,000 Confederate troops, and most important completely turned the tide in their long and frustrating campaign against Vicksburg. As the beaten Confederates streamed into the city panic ensued among the residents. But Pemberton carefully placed two fresh divisions already holding Vicksburg at key places along the line of earthworks that protected the eastern approaches to the town while placing the demoralized veterans of his recent battles in less risky positions. Delayed by having to construct crossings of the Big Black River, Grant’s Federals did not pursue until May 18 but they had all the advantages now on their side. Many expected to enter Vicksburg as soon they marched the fifteen miles separating the Big Black River from the city that become the Gibraltar of the Confederacy.

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Gellman, David N. "A Conservative on the Inside." In Liberty's Chain, 189–213. Cornell University Press, 2022. http://dx.doi.org/10.7591/cornell/9781501715846.003.0009.

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This chapter mentions William Jay's letter to Garrisonian Samuel J. May in 1836, warning how the forces of democracy might pull the emancipationists from their calling as the siren song of popularity divert them from their moral mission. Despite joining the leadership of the American Anti-Slavery Society, William Jay remained suspicious of the Garrisonians' radical exuberance. The chapter highlights William Jay's critique of the language of the New England Anti-Slavery Society's (NEAS) call for convention, stressing honesty over popularity. The chapter details how William Jay betrayed his own conservative instincts by pointing out that a mere preference for property-holding requirements over universal suffrage hardly made one an advocate of white slavery. It talks about the development of William Jay's fuller understanding of the role of racial inequality in sustaining slavery and a clearer sense of how Black voices could advance emancipation.

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"The little orange tree grew." In Stirring the Pot of Haitian History, edited by Mariana Past and Benjamin Hebblethwaite, 75–118. Liverpool University Press, 2021. http://dx.doi.org/10.3828/liverpool/9781800859678.003.0006.

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The sixth chapter likens the Haitian Revolution to a cockfight and begins to question Toussaint Louverture’s uses of power. By January 26, 1801 Toussaint has become the dominant cock, largely due to his huge political organization in the Northern provinces. A hint of reproach echoes in the discourse of narrator Grinn Prominnin because of the unacknowledged debt owed by Toussaint to the masses of formerly enslaved people who participated in the Revolution. At this point the black rebels were often insufficiently armed or were pitted against one another. Some fought for personal interests, others on more general terms; the result was a weakened position. Their advantage lay in their sheer numbers and common determination to become free. In 1793 Toussaint tapped into this energy by declaring the goal of universal freedom and liberty for Saint-Domingue, a political and tactical move that assured the former enslaved people’s loyalty to him. Once his organization solidified, he allied himself with French forces, against the Spanish and British (on whose side other rebel leaders were fighting). By 1795, Spain was defeated, and Saint-Domingue was controlled by three sectors: the new French political commissioner (Lavaud), the freedmen (Vilatte, Beauvais, and Rigaud), and Toussaint’s army. Major contradictions—economic, political, and military—divided the masses from the leaders in the latter group; often the former enslaved people were forced to work the land for the benefit of the revolutionary generals. Meanwhile, both inside and outside of Saint-Domingue, people began to distrust the paper money issued by the revolutionary state, and its value decreased. The war in the South took form, with Toussaint positioned against Rigaud. France’s third civil commissioner, Sonthonax, arrived in 1796 and was determined to crush the British and the mulatto generals’ troops. Sonthonax named Toussaint the leading general and Rigaud an outlaw. But Toussaint had Sonthonax expelled from Saint-Domingue the following year due to their several disagreements (including the fact that Sonthonax promoted Moyse Louverture to the rank of general, passing over several other leaders in Toussaint’s army). Meanwhile, in France, the political situation was becoming more conservative, and Toussaint feared that the former colonists would return to seize their property. In a dog-eat-dog society, every class has economic, political, and ideological interests; the freedmen and newly freed slaves were at odds. Toussaint subsequently repulsed Hédouville (who was sent by France as an agent of the Directory, charged with implementing reforms) and fought a vicious war in the South against Rigaud, the dominant mulatto general, thus deepening the racial divisions in the general population. Although Rigaud took a racial approach himself, Toussaint’s demagogy encouraged this social poison to pit the masses of formerly enslaved people against the mixed-race people, a problem reflecting Haiti’s hereditary ideological disease. Toussaint’s primary interests were commerce, money and the trappings of power. So intent was Toussaint on keeping Saint-Domingue afloat economically that he imposed strictures on the formerly enslaved people through a “rural work code,” forcing them to either remain on the same plantations where they had previously toiled or face severe punishment (including death). The idea of “freedom for all” thus began to lose its meaning. England and the United States began to exert pressure on Saint-Domingue as well. Before the War of the South between Toussaint and Rigaud, blacks and mixed-race people were allied against France, but afterwards each group sought its own type of Haitian independence. The beginning of the end of Toussaint’s power came about when the rebel leader fell into the Rigaud’s trap in the afè Koray [Corail Affair]; he nevertheless continued to fight for several more years. Toussaint’s leadership style moved to demagogy, and after 1799, plots mushroomed everywhere against him. The other rebel general, Jean-Jacques Dessalines, did not play upon social tensions in the same way that Toussaint did: instead of using race as a wedge issue, he allowed a group of mixed race people to join the rebel army, which raised everyone’s spirits and frightened the enemy. Toussaint’s organization was closer to the interests of the masses than Rigaud’s. With Dessalines, he convinced several maroon groups to fight against Rigaud; Dessalines won the South soon afterwards. The war of the South helped advance the larger revolution in Saint-Domingue. Once Rigaud was defeated, Toussaint was the only serious cock in the former colony. Freedom for everyone was the main interest of his organization, and he unified the country around it; Dessalines and Pétion ultimately worked together to help repulse Leclerc’s invasion of 1802. The freedmen’s advantage was blunted before they could take advantage of others. The former slaves grew stronger as a result. Despite Toussaint’s demagogy, the revolution was holding strong; though Toussaint still occupied a position of authority, there remained many contradictions in his camp.

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Тези доповідей конференцій з теми "BLANK HOLDING FORCE"

He, Sijun, Xin Wu, and S. Jack Hu. "Formability Enhancement for Tailor-Welded Blanks Using Blank Holding Force Control." In ASME 2001 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/imece2001/med-23327.

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Abstract Tailor-welded blanks (TWB) are widely used for stamped auto panels because of their great benefits such as weight and cost reduction. However, the weld line in a tailor-welded blank causes serious concerns in formability because it induces material discontinuity and additional inhomogeneous stress/strain distribution. This paper proposes a blank holding force (BHF) control strategy to control the weld line movement, distribute the deformation more uniformly and improve TWB formability. The control methodology is developed based on a simplified 2-D sectional analytical model that estimates the stress/strain distribution and the required BHFs for each side of flange with dissimilar materials. The model can be further extended to 3-D by superimposing the 2-D sectional analysis results around the entire binder ring and thus determining required BHF for the whole panel. Finite element simulations are performed to study the effects of forming parameters on the weld line movement. Experiments have been conducted to verify the analytical model and partial finite element simulations. Both analysis and experiments demonstrated that a lower BHF should be applied on the thicker blank side to allow more metal to flow in for obtaining more uniform strain distribution. The proposed BHF control is proven to be a good solution to enhance TWB formability.

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Li, Hao, Qiang Wang, and Fang He. "Optimization of Variable Blank Holder Force for Electromagnetic Blank Holding Technology." In 2019 Chinese Control Conference (CCC). IEEE, 2019. http://dx.doi.org/10.23919/chicc.2019.8865083.

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Hishida, Yuji, and Robert H. Wagoner. "Experimental Analysis of Blank Holding Force Control in Sheet Forming." In International Congress & Exposition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 1993. http://dx.doi.org/10.4271/930285.

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Mishra, Nemisha, Dilip Sutariya, and K. Narasimhan. "Influence of Variable Blank Holding Force on the Drawing Behavior of Steel Sheets." In THE 8TH INTERNATIONAL CONFERENCE AND WORKSHOP ON NUMERICAL SIMULATION OF 3D SHEET METAL FORMING PROCESSES (NUMISHEET 2011). AIP, 2011. http://dx.doi.org/10.1063/1.3623701.

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Chen, L. "Controlled FEM simulation ways of blank holding force in sheet metal forming process." In NUMISHEET 2005: Proceedings of the 6th International Conference and Workshop on Numerical Simulation of 3D Sheet Metal Forming Process. AIP, 2005. http://dx.doi.org/10.1063/1.2011205.

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Niancong Liu and Fang Fang. "Effects of property parameters and blank holding force on the deformability of sheet metal in deep drawing." In 2011 Second International Conference on Mechanic Automation and Control Engineering (MACE). IEEE, 2011. http://dx.doi.org/10.1109/mace.2011.5986909.

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Wang, Wu-Rong, and Guan-Long Chen. "The Optimization of Variable Blank Holder Force for Sheet Metal Stamping." In ASME 2006 International Manufacturing Science and Engineering Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/msec2006-21020.

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This paper focuses on the research of blank holding force (BHF) and proposes a new strategy to optimize the variable BHF and determine the drawing limit under the variable BHF. The optimization strategy is based on the analysis of BHF formability window and integrated into FEM code to obtain time or/and spatial optimal BHF that applies on binders. And then a stepped rectangular box of 60 mm drawing height with segmented binders and a cylinder cup without die bottom are adopted to validate the optimization strategy. Firstly, constant BHF FEM simulations through careful experiment design are conducted to discover the drawing limit height under maximum constant BHF. Secondly, FEM simulation combining the new BHF optimization strategy is carried and the optimal profile of variable BHF is determined for both step box and cylinder cup during the whole punch stroke. The result shows this stepped box could be formed successfully using 5754-0 aluminum alloy sheet, while the maximum drawing height under constant BHF is 45mm. And the drawing limit of cylinder box under optimal BHF could reach the drawing height of 61mm, which is greatly increased comparing with maximum of 47mm under constant BHF. Finally, the constant BHF experiment and the derived trajectory of optimal BHF of both geometries are verified on a multipoint variable BHF hydraulic press and the experiment results correspond well with those of FEM simulation. This new BHF optimization strategy not only helps to determine time and spatial optimal BHF for known geometry, but also assists to design maximum drawing height for unknown geometry, which makes it an effective method.

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Tseng, Huang-Chi, Zong-Chun Wu, Chinghua Hung, and Ming-Hu Lee. "Investigation on Sheet Hydroforming Process of Titanium/Aluminum Clad Metal Housing." In ASME 2010 International Manufacturing Science and Engineering Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/msec2010-34047.

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In this research, the sheet hydroforming process (SHF) was adopted to form a Ti/Al clad metal housing with complex shape. Nowadays, SHF has been widely accepted for the production of components characterized by high surface quality, precise dimensional accuracy together with high drawing ratio. For investigating the formability of the Ti/Al clad metal housing through SHF, the concept of virtual film were developed with explicit finite element method. First, the simulation model was verified by comparing the deformation of the blank obtained from experiments. Through finite element simulations, several significant process parameters such as holding force, tooling geometry, blank dimensions, single-stage (with pre-bulging effect) and multi-stages SHF were analyzed for improving formability of the Ti / Al clad metal housing during SHF.

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Yoshihara, S., A. Takahashi, M. Saito, B. J. MacDonald, and K. Manabe. "Development of Fuzzy Inference System With Learning Algorithm for Determining Press-Forming Conditions." In ASME 2010 International Manufacturing Science and Engineering Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/msec2010-34020.

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A fuzzy inference system with an associated database was developed in order to determine the forming conditions required to obtain the objective height of a drawn cup using magnesium alloy sheet. The results from both experimental and finite element analyses (FEA) have been used for constructing the database which contains information on the forming conditions used and the resultant height of the drawn cup. A case study utilizing circular-cup deep-drawing was used to test the inference system, whereby experimental results for the height of the drawn cup using specific forming conditions (temperature, blank size and blank holding force) agreed with those predicted using the inference system. This confirms the validity of the inference system. Furthermore, a learning method was developed in order to improve the system using further experimental results, the FEA results and a fuzzy algorithm. The experimental analysis showed good agreement between the required objective height and the experimentally measured height of the drawn cup.

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Garde, Shubham, Ranveer Patil, Tyler Grimm, and Laine Mears. "Electrically Assisted Stamping." In ASME 2022 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/imece2022-96916.

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Abstract The conventional stamping manufacturing process has certain limitations that need to be considered throughout the product design process, including the thickness of the blank, geometry of the product, and the drawing force. If the limitations are not considered during the design and manufacturing, they become defects such as wrinkles, excessive thinning, rupture, and spring back. The outcome of the defects is an increase in costs, rework, pre-processing of material (Heat Treatment), and the most important factor, time. To overcome defects, standard alternatives are changing the material composition, blank thickness, or the product design. This research aims to reduce the defects by keeping the design and the material the same as considered during the design phase. Electrically assisted manufacturing is used in the stamping process to eliminate defects. Electrically Assisted Manufacturing has been proven successful in increasing the workability of the workpiece. In this method, controlled electricity passes through the workpiece, blank holder, or the dies during the manufacturing process, which heat the blank. 5052-H32 Aluminium with a thickness of 0.5 mm was used for this study. Previous research indicates that this EAM technique can be used in forging, which is called Electrically Assisted Forging, to improve the formability of the workpiece. This research provides insights into the implementation of Electrically Assisted Forging in the stamping process. In the Electrically Assisted Stamping process, the heat produced due to electricity will temporarily change the material properties and increase its elasticity. Once the temporary elastic limit is achieved, the stamping process will begin. The current flow in pulses will continue until the stamping is completed. The method proposed in this paper considered three important parameters; the amplitude of the current, current holding time, and feed rate of the stamping machine. These parameters were used with different combinations during the testing. Using the data generated of drawing force from the Instron machine was used to plot different types of comparison graphs, which ultimately resulted in direct relation between current and drawing force.

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