Study of the Tool Geometry Influence in Indentation for the Analysis and Validation of the New Modular Upper Bound Technique

Bermudo, C.; Sevilla, L.; Martı́n, Francisco; Vilches, Francisco Javier Trujillo

doi:10.3390/app6070203

Cited by 7 publications

(6 citation statements)

References 25 publications

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“…Based on previous studies, where an indentation process was also simulated with a wider variety of materials [ 25 , 26 ], the optimal mesh is shown in Table 2 . A 1/10 relation means that the elements of the second mesh window are 10 times the size of the elements of the first window.…”

Section: Methodsmentioning

confidence: 99%

“…The FEM software used offers different friction values depending on the process simulated, with 0.12 being the appropriate value for cold forming [ 24 ]. Notwithstanding, in previous studies [ 25 , 26 ] is it established that the friction force can be neglected due to the total force that the punch needs to achieve to obtain the desired deformation.…”

Section: Methodsmentioning

confidence: 99%

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Material Flow Analysis in Indentation by Two-Dimensional Digital Image Correlation and Finite Elements Method

2017

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The present work shows the material flow analysis in indentation by the numerical two dimensional Finite Elements (FEM) method and the experimental two-dimensional Digital Image Correlation (DIC) method. To achieve deep indentation without cracking, a ductile material, 99% tin, is used. The results obtained from the DIC technique depend predominantly on the pattern conferred to the samples. Due to the absence of a natural pattern, black and white spray painting is used for greater contrast. The stress-strain curve of the material has been obtained and introduced in the Finite Element simulation code used, DEFORM™, allowing for accurate simulations. Two different 2D models have been used: a plain strain model to obtain the load curve and a plain stress model to evaluate the strain maps on the workpiece surface. The indentation displacement load curve has been compared between the FEM and the experimental results, showing a good correlation. Additionally, the strain maps obtained from the material surface with FEM and DIC are compared in order to validate the numerical model. The Von Mises strain results between both of them present a 10–20% difference. The results show that FEM is a good tool for simulating indentation processes, allowing for the evaluation of the maximum forces and deformations involved in the forming process. Additionally, the non-contact DIC technique shows its potential by measuring the superficial strain maps, validating the FEM results.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Material Flow Analysis in Indentation by Two-Dimensional Digital Image Correlation and Finite Elements Method

2017

Self Cite

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“…On the basis of previous studies [52][53][54], the optimal mesh is established with 1000 elements, two mesh windows with a 1/10 relation, and remeshing every two steps to avoid element distortion. A plane strain conditions is considered for the 2D analysis taking into account the dimensions of the specimen and the punch.…”

Section: Equipmentmentioning

confidence: 99%

2D–3D Digital Image Correlation Comparative Analysis for Indentation Process

et al. 2019

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Nowadays, localized forming operations, such as incremental forming processes, are being developed as an alternative to conventional machining or forming techniques. An indentation process is the main action that takes places in these forming activities, allowing small, localized deformations. It is essential to have the knowledge of the material behavior under the punch and the transmitted forces to achieve correct control of the entire procedure. This paper presents the work carried out with the digital image correlation (DIC) technique applied to the study of the material flow that takes place under an indentation process. The material flow analysis is performed under 2D and 3D conditions, establishing the methodology for the calibration and implementation for each alternative. Two-dimensional DIC has been proven to be a satisfactory technique compared with the 3D method, showing results in good agreement with experimental tests and models developed by the finite element method. Notwithstanding, part of the indented material flows under the punch, emerging on the front surface and generating a dead zone that can only be addressed with a 3D technique. So, the main objective is to carry out a comparison between the 2D and 3D techniques to identify if the 3D application could be mandatory for this type of process. Also, a 2D-3D mix analysis is proposed for study cases in which it is necessary to know the material flow in that specific area of the workpiece.

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“…Besides the finite element simulation and experimental testing, the development of analytical methods is an active field as well [18]. Analytical modelling of the hydrodynamic drawing process is proposed in [19], analyzing the effect of the geometry of workpiece and die, the work hardening effects of materials, and fluid properties to determine the fluid film thickness, concluding that a stable fluid film can be established for low drawing speeds combining both a multiple reduction die and a supply of lubricant at high pressures to the inlet of the dies.…”

Section: Introductionmentioning

confidence: 99%

Guidelines for Selecting Plugs Used in Thin-Walled Tube Drawing Processes of Metallic Alloys

Rubio¹,

Camacho²,

Pérez³

et al. 2017

Metals

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Abstract:In this paper, some practical guidelines to select the plug or set of plugs more adequate to carry out drawing processes of thin-walled tubes carried out with fixed conical inner plug are presented. For this purpose, the most relevant input parameters have been considered in this study: the tube material, the most important geometrical parameters of the process (die semiangle, α, and cross-sectional area reduction, r) and the friction conditions (Coulomb friction coefficients, µ 1 , between the die and the tube outer surface, and µ 2 , between the plug and the tube inner surface). Three work-hardening materials are analyzed: the annealed copper UNS C11000, the aluminum UNS A91100, and the stainless steel UNS S34000. The analysis is realized by means of the upper bound method (UBM), modelling the plastic deformation zone by triangular rigid zones (TRZ), under the validated assumption that the process occurs under plane strain conditions. The obtained results allow establishing, for each material, a group of geometrical parameters, friction conditions, a set of plugs that make possible to carry out the process under good conditions, and the optimum plug to carry out the process using the minimum amount of energy. The proposed model is validated by means of an own finite element analysis (FEA) carried out under different conditions and, in addition, by other finite element method (FEM) simulations and real experiments taken from other researchers found in the literature (called literature simulations and literature experimental results, respectively). As a main conclusion, it is possible to affirm that the plug that allows carrying out the process with minimum quantity of energy is cylindrical in most cases.

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Study of the Tool Geometry Influence in Indentation for the Analysis and Validation of the New Modular Upper Bound Technique

Cited by 7 publications

References 25 publications

Material Flow Analysis in Indentation by Two-Dimensional Digital Image Correlation and Finite Elements Method

Material Flow Analysis in Indentation by Two-Dimensional Digital Image Correlation and Finite Elements Method

2D–3D Digital Image Correlation Comparative Analysis for Indentation Process

Guidelines for Selecting Plugs Used in Thin-Walled Tube Drawing Processes of Metallic Alloys

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