An evaluation of through-thickness deformation mechanisms in single point incremental sheet forming using a dual-level finite-element model

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An evaluation of through-thickness deformation mechanisms in single point incremental sheet forming using a dual-level finite-element model

Khamis Essa, Peter Hartley

School of Mechanical Engineering, College of Engineering and Physical Sciences,University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.

DOI:

https://doi.org/10.7494/cmms.2012.1.0382

Abstract:

Single point incremental forming (SPIF) is a process with the capability to form complex geometries using a tool of very simple geometry, without the need for a matching die. At present, through-thickness modes of deformation and the existence of through-thickness shear are not clear. The objectives of this report are firstly, to establish a computational methodology to study the deformation mechanism of SPIF and secondly, to provide a clear description of the deformation modes that take place through the sheet thickness. The methodology is, in essence, a multi-level approach, although in this example only two levels are necessary. In this paper, a 3-D implicit finite-element (FE) model of the complete sheet being formed, with two elements through the thickness and a second-level FE model of a smaller segment of the sheet, with seven elements through its thickness, are used in a dual-level approach. The results show that the full model is capable only of exploring the principal characteristics of the deformation, normal strains and the final product geometries. The second-level model demonstrates a capability to predict more accurately the deformation modes through the sheet thickness and shows the influence of tool friction and diameter on the through-thickness shear strains. A combination of bending, stretching and thinning modes of deformation in addition to through thickness shear is found. The results obtained provide a more complete description of through-thickness deformation mechanisms.

Cite as:

Essa, K., & Hartley, P. (2012). An evaluation of through-thickness deformation mechanisms in single point incremental sheet forming using a dual-level finite-element model. Computer Methods in Materials Science, 12(1), 37 – 50. https://doi.org/10.7494/cmms.2012.1.0382

Article (PDF):

Keywords:

Asymmetric incremental sheet forming, Single point incremental forming, Finite element analysis, Throughthickness deformation modes, Shear strain

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