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This paper gives a review of the finite element techniques (FE)applied in the area of material processing. The latest trends in metalforming, non‐metal forming and powder…
This paper gives a review of the finite element techniques (FE) applied in the area of material processing. The latest trends in metal forming, non‐metal forming and powder metallurgy are briefly discussed. The range of applications of finite elements on the subjects is extremely wide and cannot be presented in a single paper; therefore the aim of the paper is to give FE users only an encyclopaedic view of the different possibilities that exist today in the various fields mentioned above. An appendix included at the end of the paper presents a bibliography on finite element applications in material processing for the last five years, and more than 1100 references are listed.
Sheet metal forming is a process of shaping thin sheets of metal by applying pressure through male or female dies or both. In most of used sheet‐formating processes the…
Sheet metal forming is a process of shaping thin sheets of metal by applying pressure through male or female dies or both. In most of used sheet‐formating processes the metal is subjected to primarily tensile or compressive stresses or both. During the last three decades considerable advances have been made in the applications of numerical techniques, especially the finite element methods, to analyze physical phenomena in the field of structural, solid and fluid mechanics as well as to simulate various processes in engineering. These methods are useful because one can use them to find out facts or study the processes in a way that no other tool can accomplish. Finite element methods applied to sheet metal forming are the subjects of this paper. The reason for writing this bibliography is to save time for readers looking for information dealing with sheet metal forming, not having an access to large databases or willingness to spend own time with uncertain information retrieval. This paper is organized into two parts. In the first one, each topic is handled and current trends in the application of finite element techniques are briefly mentioned. The second part, an Appendix, lists papers published in the open literature. More than 900 references to papers, conference proceedings and theses/dissertations dealing with subjects that were published in 1995‐2003 are listed.
This paper gives a review of the finite element techniques (FE) applied in the area of material processing. The latest trends in metal forming, non‐metal forming, powder…
This paper gives a review of the finite element techniques (FE) applied in the area of material processing. The latest trends in metal forming, non‐metal forming, powder metallurgy and composite material processing are briefly discussed. The range of applications of finite elements on these subjects is extremely wide and cannot be presented in a single paper; therefore the aim of the paper is to give FE researchers/users only an encyclopaedic view of the different possibilities that exist today in the various fields mentioned above. An appendix included at the end of the paper presents a bibliography on finite element applications in material processing for 1994‐1996, where 1,370 references are listed. This bibliography is an updating of the paper written by Brannberg and Mackerle which has been published in Engineering Computations, Vol. 11 No. 5, 1994, pp. 413‐55.
Offers guidelines for surveyors dealing with pitched metal roofs built between the early 1970s and the present. Discusses roof pitch recommendations, insulation, linings, fastenings, leaks, corrosion, and sealants. Summarises that surveyors should consider particular points of corrosion, condensation, leaks and insulations when dealing with metal roofs.
To study the influence of process and product parameters on the properties of products in incremental sheet metal‐forming; to create models for process optimisation and to…
To study the influence of process and product parameters on the properties of products in incremental sheet metal‐forming; to create models for process optimisation and to introduce an approach to incremental forming process optimisation.
A new flexible sheet metal‐forming technique, incremental forming, has been studied. The technique can be viewed as a rapid prototyping/manufacturing technique for sheet metal parts. To analyse the process, an experimental study and finite element analysis were performed. For the optimal design of incremental forming process non‐linear mathematical programming was used. To estimate the limitations and main parameters of the process, a complex model was developed.
Introducing optimisation procedures for the incremental forming process allows users to increase productivity and to assure quality.
As finite element analysis of the process is time‐consuming in real life situations, a future study should include creating analytical models for process modelling.
The described approach can be used in practice to improve competitiveness of companies producing sheet metal prototypes.
This paper offers guidelines for shortening processing time of sheet metal prototypes for engineers and researchers. The optimisation that is based on experimental/theoretical/numerical models of incremental forming process has not been covered before in the scientific literature.
The initiation and growth of wrinkles are influenced by many factors such as stress ratios, the mechanical properties of the sheet material, the geometry of the workpiece…
The initiation and growth of wrinkles are influenced by many factors such as stress ratios, the mechanical properties of the sheet material, the geometry of the workpiece, contact condition, etc. It is difficult to analyze wrinkling initiation and growth while considering all the factors because the effects of the factors are very complex and studies of wrinkling behavior may show a wide scattering of data even for small deviations in factors. The finite element analyses of wrinkling initiation and growth in sheet metal forming process provide detailed information about the wrinkling behavior of sheet metal. The direct analysis of wrinkling initiation and growth, however, brings about a little difficulty in complex industrial problems because it requires large memory size and long computation time. From the industrial viewpoint of tooling design, therefore, readily available information on the possibility and location of wrinkling is sometimes more preferable to detailed and time‐consuming analysis results. In the present study, in order to give such readily available information on wrinkling initiation, the wrinkling factor, which shows the locations and relative possibility of wrinkling initiation, is proposed as a convenient tool of relative wrinkling estimation based on the energy criterion. The reliability of the wrinkling factor is verified through the buckling analyses of sheet strips. The location and relative possibility of wrinkling initiation are predicted by calculating the wrinkling factor in various sheet metal forming processes such as cylindrical cup deep drawing, spherical cup deep drawing, and elliptical cup deep drawing. Finally, the wrinkling factor proposed in the present study is also implemented in the prediction of wrinkling in the door inner stamping process. For verification of the calculated wrinkling factor, detailed zone analyses with fine meshes are carried out for the regions where wrinkling is predicted.
Addresses the computational aspects involved in the numerical simulation of sheet stamping processes. Focuses on some numerical aspects of the intrinsic complexity of…
Addresses the computational aspects involved in the numerical simulation of sheet stamping processes. Focuses on some numerical aspects of the intrinsic complexity of these problems, the first of which is the necessity to take into account properly membrane and bending effects. Presents a well‐adapted shell element. The second aspect concerns the description and the implementation of the initial orthotropic plastic behaviour for sheet metal parts, based on a formulation in a rotating frame using the initial microstructure rotation. The stress calculation algorithm is based on a particular implementation of the elastic predictor‐plastic corrector method. The last aspect concerns the solution procedures with a particular development concerning the treatment of the blankholder load as a constraint. A set of computational results validated with experiments prove the accuracy of the proposed approach in solving stamping problems.
“V-bending” is the most commonly used bending process in which the sheet metal is pressed into a “V-shaped” die using a “V-shaped” punch to form a required angular bend…
“V-bending” is the most commonly used bending process in which the sheet metal is pressed into a “V-shaped” die using a “V-shaped” punch to form a required angular bend. When the punch is removed after the operation, because of elastic recovery, the bent angle varies. This shape discrepancy is known as spring back which causes problems in the assembly of the component in the modern aerospace industry. Regarding the optimization of spring-back accuracy, this research will illustrate the laws of the transition area (TA) of the nondeformation area (NDA) during the 90° “V-shape” bending process.
According to the traditional “V-bending” process to optimize the spring-back accuracy, the bent sheets are divided into deformation area (DA) and NDA. For this reason, the traditional “V-bending” process may prolong error to optimize the spring-back accuracy because NDA has a certain amount of deformation, which the researcher always avoids. Firstly, bent sheets are divided into three parts in this research: DA, TA and NDA to avoid the distortion error in TA that are not considered in the NDA in traditional theory. Then, the stress and strain in the DA and TA were discussed during theoretical derivation and some hypotheses were proposed. In this research, the interval, position and distortion degree of the TA of the bending sheet are used by finite element analysis. Finally, V-shape bending tests for aluminum alloy at room temperature are used and labeled all the work pieces' TAs to realize the deformation amount in the TA.
The bending radius does not affect the range of the TA, it only changes the position of TA in the bending sheet. It is evident that the laws of TA were explored in the width direction and gradually changed from the inner layer to the outer layer based on the ratio of width and thickness of the bending plate/sheet.
In the modern aerospace industry, aircraft manufacturing technology must maintain high accuracy. This research has practical value in the 90° “V-shape” bending of metal sheets and the development of its spring-back accuracy.
Past research on collectivist-democratic organizations has attributed their distinctiveness to their socio-political goals and democratic decision-making and largely…
Past research on collectivist-democratic organizations has attributed their distinctiveness to their socio-political goals and democratic decision-making and largely ignored their work processes. This ethnographic study examines how such organizations resist alienating forms of work even in the face of direct competition with for-profit companies. It focuses on Scopix, a French cooperative sheet-metal factory where the first author spent one year as a shop-floor worker. Cooperators there developed various practices to retain an emancipatory dimension to their work, regularly putting forward “craft ethics” as a counterweight to the sheet-metal industry’s drive to rationalize work processes. Drawing on the sociology of worth, the authors analyze how these practices emerged from the arrangements that workers made between the industrial world on the one side and the domestic and inspired worlds on the other. This study contributes to the literature into two main ways. First, the authors refine the sociology-of-worth framework by conceptualizing the emancipatory dimension of work as the result of ad hoc arrangements between different worlds. Second, the authors highlight the need for the literature on collectivist-democratic organizations to increase its focus on work, introducing the concept of work degeneration as a step in that direction.
ALL‐METAL construction, mainly in aluminium alloy and with thin sheet covering or skin, has been nigh universal in the American aeroplane industry for a number of years…
ALL‐METAL construction, mainly in aluminium alloy and with thin sheet covering or skin, has been nigh universal in the American aeroplane industry for a number of years. This industry has now to face three difficult problems. First, the utilization of sheet metal in building larger land and water aircraft than ever before attempted. Second, in meeting the transition stage from the production of smaller aeroplanes in, small quantities only, to moderate mass production. Third, in keeping down costs in the face of sharp rises in the price of materials and wages of labour. These problems have led in turn to important improvements and radical innovations in the methods of handling sheet metal. A brief review of modern American practice may therefore be of interest to British constructors, before describing a new method of rolling sheet and double curvatures in a special machine.