Journal ArticleDOI
The Increased Forming Limits of Incremental Sheet Forming Processes
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In this paper, a simplified process is used to gain insight into the mechanics of a broad class of incremental sheet forming processes, and the analysis shows that for a sheet with uniform proportional loading, the forming limit is increased when through thickness shear is present.Abstract:
Incremental sheet forming is known to give higher forming limits than conventional sheet forming processes, but investigation of this effect has been impeded by the computational cost of process models which include detailed predictions of through thickness behaviour. Here, a simplified process is used to gain insight into the mechanics of a broad class of incremental forming processes. The simplified process is described and shown to give increases in forming limits compared to a conventional process with the same geometry. A model of the process is set up with a commercial finite element package, validated, and used to trace the history of a ‘pin’ inserted perpendicularly into the workpiece. The history of the deformation of the ‘pin’ demonstrates significant through thickness shear occurring in the direction parallel to tool motion. This insight is used to modify an existing analysis used to predict forming limit curves. The analysis shows that for a sheet with uniform proportional loading, the forming limit is increased when through thickness shear is present, and this is proposed as an explanation for the increased forming limits of incremental sheet forming processes.read more
Citations
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Journal ArticleDOI
The mechanics of incremental sheet forming
TL;DR: In this paper, the deformation mechanism of incremental sheet forming (ISF) is examined experimentally through forming specially prepared copper sheets, and the authors measured the strain distributions through the thickness of the sheets are measured for two configurations of ISF: two-point incremental forming (TPIF) and single point incremental forming(SPIF).
Journal ArticleDOI
Theory of single point incremental forming
TL;DR: In this article, a closed-form theoretical analysis of the fundamentals of single point incremental forming is presented, which is based on membrane analysis with bi-directional in-plane contact friction and is focused on the extreme modes of deformation that are likely to be found in singlepoint incremental forming processes.
Journal ArticleDOI
An overview of stabilizing deformation mechanisms in incremental sheet forming
TL;DR: In this paper, the authors present an overview of mechanisms that have been suggested to explain the enhanced formability of incremental sheet metal forming, including contact stress, bending under tension, shear, cyclic straining, geometrical inability to grow and hydrostatic stress.
Journal ArticleDOI
Advances in anisotropy and formability
TL;DR: In this paper, a review of the experimental methods used for characterizing and modeling the anisotropic plastic behavior of metallic sheets and tubes under biaxial loading is presented together with the models and methods developed for predicting and establishing the limit strains.
Journal ArticleDOI
Generalised forming limit diagrams showing increased forming limits with non-planar stress states
Julian M. Allwood,D.R. Shouler +1 more
TL;DR: In this paper, a generalised forming limit diagram (GFLD) is proposed to allow visual representation of the resulting forming limit strains, which can be used to expand process operating windows.
References
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Journal ArticleDOI
Limit strains in the processes of stretch-forming sheet metal
TL;DR: In this paper, a theoretical analysis of the process of the generation of the groove based on anisotropic plasticity theory is presented, and the system of equations derived was solved numerically with the aid of a computer, which enabled the limiting strain of the sheet metal to be determined as a function of the material.
Journal ArticleDOI
Asymmetric single point incremental forming of sheet metal
Jack Jeswiet,Jack Jeswiet,Fabrizio Micari,Fabrizio Micari,Gerhard Hirt,Gerhard Hirt,Alan N Bramley,Alan N Bramley,Joost Duflou,Joost Duflou,Julian M. Allwood,Julian M. Allwood +11 more
TL;DR: Asymmetric Incremental Sheet Forming has the potential to revolutionize sheet metal forming, making it accessible to all levels of manufacturing as discussed by the authors, and has been shown to be a state-of-the-art in sheet metal manufacturing.
Journal ArticleDOI
A more general model for forming limit diagrams prediction
TL;DR: In this paper, the authors developed a more general code for the prediction of forming limit diagrams (FLDs), which is composed of a main part and several subroutines, which allow the implementation of different hardening laws, yield functions or constitutive equations.