Material data identification to model the single point incremental forming process

Abstract

In this study, the Single Point Incremental Forming process (SPIF) is applied on a specific aluminium alloy used in the aerospace industry since this technique and material combine a low specific weight, high strength and stiffness properties and high strain levels. To be able to optimize the process, a model and its material parameters are required. It was noticed that a simple isotropic hardening model was not sufficient to provide an accurate tool force prediction [1]. Therefore an elasto-plastic law with a mixed isotropic-kinematic hardening is investigated. The inverse method coupled with the Finite Element (FE) code: "Lagamine" [2] is used to fit the material data of this complex law. In order to validate the model and the material data, a Line test and a Cone test are used.

Experimental and numerical study of an AlMgSc sheet formed by an incremental process

“…5) were simultaneously used in the inverse method. Indeed, Bouffioux et al (2008Bouffioux et al ( , 2010 observed that simple classical tests inducing in-plane stresses were not sufficient to describe the material behaviour during the SPIF process. The indent test gave the missing information about the out-of-plane material behaviour since it induces through thickness shear.…”

“…However such information is accurate only if the simulation has been validated by experiments. Previous researches by Bouffioux et al (2008Bouffioux et al ( , 2010 demonstrated the effect of the material parameter identification method, the material model itself (Flores et al, 2007), the Finite Element Method (FEM) strategy such as the explicit or implicit choice (Henrard, 2009), the finite element type: solid or shell (Eyckens et al, 2010a;Henrard et al, 2010), the mesh density and the contact model (Henrard, 2009). Eyckens (2010b) incorporated through-thickness shear (TTS), also known as out-ofplane shear, into a Marciniak-Kuczynski model and observed that the through-thickness shear has a significant effect on the increasing forming limit curves of the process.…”

“…Furthermore, the simulations usually require a very high computation time because the tool path is long and can be complex. The combination of different strategies described by Bouffioux et al (2008Bouffioux et al ( , 2010, Lequesne et al (2008) to improve the material and numerical models and applied on this study aimes to be able to accurately simulate the process with a short computation time.…”

Advances in Simulation of Two Point Incremental Forming

“…Recently, accuracy gains in force prediction were attained by the use of a mixed hardening law in [9]. Kinematic hardening is related with alternating strains in the material and could be the reason of the maximum discrepancy obtained at minimum Δθ as a consequence of the augmentation of tool passes over the same material spot.…”

Single point incremental forming: An assessment of the progress and technology trends from 2005 to 2015

“…: effect of different mesh densities, too stiff behaviour of the element used in Lagamine and too high penalty used in the Lagamine contact model. Bouffioux et al [136][137][138] developed an inverse method for adjusting the material parameters with experimental measurements. This involved doing line tests that deformed a flat blank along a pre-defined linear geometry and using the force data from these tests to tune the FE model.…”