A methodology for prediction of forming limit stress diagrams considering the strain path effect

Assempour, Ahmad; Hashemi, Ramin; Abrinia, Karen; Ganjiani, Mehdi; Masoumi, E.

doi:10.1016/j.commatsci.2008.09.025

Cited by 69 publications

(34 citation statements)

References 19 publications

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“…An ANN is a set of processing elements or neurons, and connections with adjustable weights. One of the advantages of using the neural network approach is that a model can be constructed very easily based on the given input and output and trained to accurately predict process dynamics [5,6]. This modeling technique is particularly precious in processes where a complete understanding of the physical mechanisms is very complicated as in the case of sheet metal forming process.…”

Section: Artificial Neural Networkmentioning

confidence: 99%

“…The construction of a FLD that suits for all above variation needs a lot of experimental work to be carried out. With the aim to reduce the experimental work for constructing FLD, many researchers have developed no of mathematical models [5][6][7]. In recent years, researchers are attempting to develop ANN model, which has universal approximation capability and more accurate in predicting any system [8].…”

Section: Introductionmentioning

confidence: 99%

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Modelling the correlation between the geometrical features and the forming limit strains of perforated Al 8011 sheets using artificial neural network

Elangovan¹,

Narayanan²,

Narayanasamy³

2010

Int J Mater Form

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In the recent years, sheet metals are produced with perforations in various shapes and patterns to improve the appearance of sheet and to save weight of components. As in conventional metal sheets, it is important to form the perforated sheet metals also within their safe strain regions to avoid the forming failures like necking, fracture and wrinkling. The Forming Limit Diagram (FLD) is an appropriate tool to determine the forming limit strains. The limiting strains of perforated sheet metals mainly depend on the geometry of the perforations and forming variables. This leads to large increase in number of test to be conducted with various geometry and forming variables for determining the forming limit strain for perforated sheets. Aiming to reduce the number of experiments needed, in this work, an Artificial Neural Network (ANN) model has been developed for forming limit diagram of perforated Al 8011 sheets based on experimental results and correlated with the geometrical features of the perforated sheets. This model is a feed forward back propagation neural network (BPNN) with a set of geometrical variables as its inputs and the safe true strains as its output. This ANN model can be applied for prediction of FLD of perforated sheet having any geometry.

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Section: Artificial Neural Networkmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modelling the correlation between the geometrical features and the forming limit strains of perforated Al 8011 sheets using artificial neural network

Elangovan¹,

Narayanan²,

Narayanasamy³

2010

Int J Mater Form

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show abstract

“…The concept of the FLD has been extensively applied to predict formability to the sheet metal forming industry because of its simplicity, straightforwardness and comfort of use. The FLC is dynamic in nature, whose shape and position significantly alter with strain paths [3][4][5][6][7][8][9]. Therefore, the use of conventional FLD might be restrictive because the sheet metals experience nonlinear strain paths during the real industrial forming operations.…”

Section: Introductionmentioning

confidence: 99%

Path independent limiting criteria in sheet metal forming

Paul

2015

Journal of Manufacturing Processes

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“…3,4], which makes the stress-based criterion (FLSD) more appropriate to characterize formability [e.g. 5,6].…”

Section: Introductionmentioning

confidence: 99%

Local bifurcation and instability theory applied to formability analysis

et al. 2011

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The design and optimization of both sheet metal formed parts and processes are nowadays carried out virtually making use of numerical tools by finite element analysis. Such virtual try-out approach contributes with significant savings in terms of money, time and effort in the design, production and process set-up of deep drawn parts. The analysis of either forming success operation or surface defects, in each of the development phases, is generally performed by means of the material's forming limit diagram (FLD), since it allows to define a safe region that reduces the probability of: (i) necking; (ii) wrinkling and (iii) large deformation occurrence. However, the FLD represented in the strain space is known to present some disadvantages. To overcome this problem, Ito and Goya proposed a local bifurcation criterion that defines the critical state for a local bifurcation to set in as a function of the stress level to workhardening rate ratio, leading to a FLD represented in the stress space. This suggests that the FLD obtained is completely objective in the sense that it is completely independent of the strain or stress history paths (Ito et al. 2000). In this work the Ito and Goya model is used to evaluate formability, as well as fracture mode and direction on the deep drawing of a square cup. Since the analysis is performed based on the stress state, it is also possible to determine an instability factor that "measures" the degree of acceleration by current stress for the local bifurcation mode towards fracture. The selected example highlights the potential use of the criterion which, once combined with the finite element analysis, can undeniably improve the mechanical design of forming processes.

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A methodology for prediction of forming limit stress diagrams considering the strain path effect

Cited by 69 publications

References 19 publications

Modelling the correlation between the geometrical features and the forming limit strains of perforated Al 8011 sheets using artificial neural network

Modelling the correlation between the geometrical features and the forming limit strains of perforated Al 8011 sheets using artificial neural network

Path independent limiting criteria in sheet metal forming

Local bifurcation and instability theory applied to formability analysis

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