Author: J. D. Bressan
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Anglo Kamel Tadros
Publisher:
ISBN:
Category :
Languages : en
Pages : 100

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Book Description
An experimental and theoretical study of limit strains for the plastic deformation of sheet metals is presented. It is postulated that incipient grooves may appear during stable plastic flow but that a single groove will not exhibit continuing growth until diffuse necking occurs. It is therefore proposed that the well known Marciniak and Kuczynski analysis should be applied to a material from the time diffuse necking sets in. The total limit strain will then be the sum of the strains up to general instability and the strain necessary to give a localized neck according to the modified application of the Marciniak and Kuczynski analysis. The difficulty of assigning the thickness parameter f at the general instability condition remains. It would seem reasonable, however, to expect the value of f at diffuse necking to depend in some manner on the amount of plastic work expended on the material up to that point. Experiments were carried out into the in-plane stretching of steel, aluminium and 70/30 brass sheets. The development of strains was studied together with measurements of limit strains for conditions between plane strain tension and balanced biaxial tension. Also, the development of surface roughness was measured at different stages of the deformation. Measurements of surface roughness for steel and aluminium at the level of the predicted instability condition demonstrated that small grooves had appeared in the sheet. The sheet materials were selected to cover a wide range of n-values and r-values. The measured limit strain for steel and aluminium could be explained in term of the theoretical model. The behaviour of the 70/30 brass was unusual in that the measured limit strains were always less than the instability strains predicted by the classical theory of Swift. The in-plane test eliminated friction and reduces the strain gradient in the region of a neck and has proved a very suitable method for the determination of limit strains.

Author: Lihong Zhao
Publisher:
ISBN:
Category : Metal stamping
Languages : en
Pages : 206

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Author: D. Koistinen
Publisher: Springer Science & Business Media
ISBN: 1461328802
Category : Technology & Engineering
Languages : en
Pages : 412

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Book Description
This volume records the proceedings of an international symposium on "ME CHANICS OF SHEET METAL FORMING: Material Behavior and Deformation Analysis." It was sponsored and held at the General Motors Research Labora tories on October 17-18, 1977. This symposium was the twenty-first in an annual series. The objective of this symposium was to discuss the research frontiers in experimental and theoretical methods of sheet metal forming analysis and, also, to determine directions of future research to advance technology that would be useful in metal stamping plants. Metal deformation analyses which provide guide lines for metal flanging are already in use. Moreover, recent advances in computer techniques for solving plastic flow equations and in measurements of material parameters are leading to dynamic models of many stamping operations. These models would accurately predict the stresses and strains in the sheet as a function of punch travel. They would provide the engineer with the knowledge he needs to improve die designs. The symposium papers were organized into five sessions: the state of the art, constitutive relations of sheet metal, role of friction, sheet metal formability, and deformation analysis of stamping operations. We believe this volume not only summarizes the various viewpoints at the time of the symposium, but also pro vides an outlook for materials and mechanics research in the future.

Author: Dorel Banabic
Publisher: Springer Science & Business Media
ISBN: 3540881131
Category : Technology & Engineering
Languages : en
Pages : 312

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Book Description
The concept of virtual manufacturing has been developed in order to increase the industrial performances, being one of the most ef cient ways of reducing the m- ufacturing times and improving the quality of the products. Numerical simulation of metal forming processes, as a component of the virtual manufacturing process, has a very important contribution to the reduction of the lead time. The nite element method is currently the most widely used numerical procedure for s- ulating sheet metal forming processes. The accuracy of the simulation programs used in industry is in uenced by the constitutive models and the forming limit curves models incorporated in their structure. From the above discussion, we can distinguish a very strong connection between virtual manufacturing as a general concept, ?nite element method as a numerical analysis instrument and constitutive laws,aswellas forming limit curves as a speci city of the sheet metal forming processes. Consequently, the material modeling is strategic when models of reality have to be built. The book gives a synthetic presentation of the research performed in the eld of sheet metal forming simulation during more than 20 years by the members of three international teams: the Research Centre on Sheet Metal Forming—CERTETA (Technical University of Cluj-Napoca, Romania); AutoForm Company from Zürich, Switzerland and VOLVO automotive company from Sweden. The rst chapter presents an overview of different Finite Element (FE) formu- tions used for sheet metal forming simulation, now and in the past.

Author: Wilko C. Emmens
Publisher: Springer Science & Business Media
ISBN: 3642219047
Category : Technology & Engineering
Languages : en
Pages : 110

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- Overview of materials and treatment aspects of manufacturability of sheet metal - Written by an industrial expert turned scientist - Concentrates on the formability of sheet metal, one of the fundamental form material is used in metalworking

Author: R. Pearce
Publisher: Springer Science & Business Media
ISBN: 9780750301015
Category : Technology & Engineering
Languages : en
Pages : 314

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Book Description
The pressing of sheet metal into useful shapes is a technology which requires an understanding of a wide range of subjects. This text is divided into three sections: processes, materials and tests. In Part 1, sheet metal forming is examined mainly from a mechanical engineering viewpoint; firstly plasticity and anisotropy, then process variables - friction, lubrication and temperature - and finally practical aspects of forming in the press-shop. Part 2 deals with the main sheet alloys at varying lengths, depending on their industrial popularity. Certain research results, showing the fallibility of the phenomenological approach, are also highlighted. A section of testing procedures concludes the volume.

Author: Douglas Dean Olander
Publisher:
ISBN:
Category :
Languages : en
Pages : 375

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Author: Robert H. Wagoner
Publisher:
ISBN:
Category : Crafts & Hobbies
Languages : en
Pages : 360

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Author: Dorel Banabic
Publisher: Springer
ISBN: 3319440705
Category : Technology & Engineering
Languages : en
Pages : 416

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Book Description
This book gives a unified presentation of the research performed in the field of multiscale modelling in sheet metal forming over the course of more than thirty years by the members of six teams from internationally acclaimed universities. The first chapter is devoted to the presentation of some recent phenomenological yield criteria (BBC 2005 and BBC 2008) developed at the CERTETA center from the Technical University of Cluj-Napoca. An overview on the crystallographic texture and plastic anisotropy is presented in Chapter 2. Chapter 3 is dedicated to multiscale modelling of plastic anisotropy. The authors describe a new hierarchical multi-scale framework that allows taking into account the evolution of plastic anisotropy during sheet forming processes. Chapter 4 is focused on modelling the evolution of voids in porous metals with applications to forming limit curves and ductile fracture. The chapter details the steps needed for the development of dissipation functions and Gurson-type models for non-quadratic anisotropic plasticity criteria like BBC 2005 and those based on linear transformations. Chapter 5 describes advanced models for the prediction of forming limit curves developed by the authors. Chapter 6 is devoted to anisotropic damage in elasto-plastic materials with structural defects. Finally, Chapter 7 deals with modelling of the Portevin-Le Chatelier (PLC) effect. This volume contains contributions from leading researchers from the Technical University of Cluj-Napoca, Romania, the Catholic University of Leuven, Belgium, Clausthal University of Technology, Germany, Amirkabir University of Technology, Iran, the University of Bucharest, Romania, and the Institute of Mathematics of the Romanian Academy, Romania. It will prove useful to postgraduate students, researchers and engineers who are interested in the mechanical modeling and numerical simulation of sheet metal forming processes.