A Complex Measuring and Evaluation System for Determination of Forming Limit Diagrams

2008 ◽  
Vol 589 ◽  
pp. 233-238 ◽  
Author(s):  
Péter Kovács ◽  
Miklós Tisza
Keyword(s):  
Numerical Simulations ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Evaluation System ◽  
Measuring System ◽  
Forming Limit ◽  
Forming Limit Curves ◽  
Complex Measuring

Forming limit curves are very important for the prediction of failure during sheet metal forming both in practical forming operations and particularly in numerical simulations. The reliability of numerical simulations in sheet metal forming processes is strongly influenced by the reliability of forming limit curves. Therefore, both the theoretical aspects and the experimental determination of the forming limit curves are challenging problems for scientific researchers and industrial practitioners as well. There are various experimental techniques and mathematical models used to determine the forming limit curves. In spite of the standardization efforts made recently by several institutions world wide, there are still significant differences in determining the forming limit curves. Recently, a new, complex measuring system capable for the automatic determination of FLCs was installed at the Department of Manufacturing Engineering. In this paper, first a short overview will be given on the theoretical background of FLCs, then the application of the complex measuring system will be shown.

Determination of FLD for Ti-6Al-4V Titanium Alloy Sheet

2016 ◽  
Vol 687 ◽  
pp. 171-178
Author(s):  
Piotr Lacki
Keyword(s):  
Titanium Alloy ◽  
Numerical Simulations ◽  
Real Time ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Forming Limit Diagram ◽  
Alloy Sheet ◽  
Forming Limit

Ti-6Al-4V is the most widely applied titanium alloy in technology and medicine due its good mechanical properties combined with low density and good corrosion resistance. However, poor technological and tribological properties make it very difficult to process, including the problems with sheet-metal forming. The best way to evaluate sheet drawability is to use Forming Limit Diagram (FLD), which represents a line at which failure occurs. FLD allows for determination of critical forming areas.The FLDs can be determined both theoretically and experimentally. Recently, special optical strain measurement systems have been used to determine FLDs.In this study, material deformation was measured with the Aramis system that allows for real-time observation of displacements of the stochastic points applied to the surface using a colour spray. The FLD was determined for Ti-6Al-4V titanium alloy sheet with thickness of 0.8 mm. In order to obtain a complete FLD, a set of 6 samples with different geometries underwent plastic deformation in stretch forming i.e. in the Erichsen cupping test until the appearance of fracture.The real-time results obtained from the ARAMIS software for multiple measurement positions from the test specimen surface were compared with numerical simulations of the cupping tests. The numerical simulations were performed using the PamStamp 2G v2012 software dedicated for analysis of sheet-metal forming processes. PamStamp 2G is based on the Finite Element method (FEM). The major and minor strains were analysed. The effect of friction conditions on strain distribution was also taken into consideration

Preliminary Studies on the Determination of FLD for Single Point Incremental Sheet Metal Forming

2012 ◽  
Vol 504-506 ◽  
pp. 863-868 ◽  
Author(s):  
Miklos Tisza ◽  
Péter Zoltán Kovács ◽  
Zsolt Lukács
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
New Technologies ◽  
Single Point ◽  
Research Work ◽  
Dimensional Accuracy ◽  
Forming Limit ◽  
Incremental Sheet Metal Forming

Development of new technologies and processes for small batch and prototype production of sheet metal components has a very important role in the recent years. The reason is the quick and efficient response to the market demands. For this reasons new manufacturing concepts have to be developed in order to enable a fast and reliable production of complex components and parts without investing in special forming machines. The need for flexible forming processes has been accelerated during the last 15 years, and by these developments the technology reaches new extensions. Incremental sheet metal forming (ISMF) may be regarded as one of the promising developments for these purposes. A comprehensive research work is in progress at the University of Miskolc (Hungary) to study the effect of important process parameters with particular emphasis on the shape and dimensional accuracy of the products and particularly on the formability limitations of the process. In this paper, some results concerning the determination of forming limit diagrams for single point incremental sheet metal forming will be described.

Advances in Plastic Anisotropy and Forming Limits in Sheet Metal Forming

2016 ◽  
Vol 138 (9) ◽  
Author(s):  
Dorel Banabic
Keyword(s):  
Numerical Simulation ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Constitutive Modeling ◽  
Metal Forming ◽  
Plastic Anisotropy ◽  
Forming Limit ◽  
Simulation Tools ◽  
The One ◽  
Forming Limit Curves

In the last decades, numerical simulation has gradually extended its applicability in the field of sheet metal forming. Constitutive modeling and formability are two domains closely related to the development of numerical simulation tools. This paper is focused, on the one hand, on the presentation of new phenomenological yield criteria developed in the last decade, which are able to describe the anisotropic response of sheet metals, and, on the other hand, on new models and experiments to predict/determine the forming limit curves.

Advances in Plastic Anisotropy and Forming Limits in Sheet Metal Forming

2015 ◽  
Author(s):  
Dorel Banabic
Keyword(s):  
Numerical Simulation ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Plastic Anisotropy ◽  
Constitutive Modelling ◽  
Forming Limit ◽  
Simulation Tools ◽  
The One ◽  
Forming Limit Curves

In the last decades, numerical simulation has gradually extended its applicability in the field of sheet metal forming. Constitutive modelling and formability are two domains closely related to the development of numerical simulation tools. This paper is focused, on the one hand, on the presentation of new phenomenological yield criteria developed in the last decade, which are able to describe the anisotropic response of sheet metals, and, on the other hand, on new models and experiments to predict/determine the forming limit curves.

An Intelligent Tool to Predict Fracture in Sheet Metal Forming Operations

2007 ◽  
Vol 344 ◽  
pp. 841-846
Author(s):  
Rosanna Di Lorenzo ◽  
Giuseppe Ingarao ◽  
Fabrizio Micari
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Production Quality ◽  
Forming Limit ◽  
Fracture Criteria ◽  
Predictive Tool ◽  
Forming Limit Diagrams ◽  
Early Results

One of the main issues in sheet metal forming operations design is the determination of formability limits in order to prevent necking and fracture. In fact, the ability to predict fracture represents a powerful tool to improve the production quality in mechanical industry. Many researchers investigated the problem here addressed, mainly studying forming limit diagrams (FLD) or developing fracture criteria which are able to foresee fracture defects for different processes. In this paper, the author present some early results of a research project focused on the application of artificial intelligence (AI) for ductile fracture prediction in sheet metal forming operations. The main advantage of the application of AI tools and in particular, of artificial neural networks (ANN), is the possibility to obtain a predictive tool with a wide applicability. The prediction results obtained in this paper fully demonstrate the usefulness of the proposed approach.

scholarly journals Methods of determination of frictional resistances in sheet metal forming of car body sheets

2018 ◽  
Vol 19 (6) ◽  
pp. 756-760
Author(s):  
Tomasz Trzepieciński ◽  
Irena Nowotyńska
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Complex Function ◽  
Forming Process ◽  
The Coefficient Of Friction ◽  
Displacement Speed ◽  
Almost All ◽  
Lubrication Conditions

The friction phenomenon existed in almost all plastic working processes, in particular sheet metal forming, is a complex function of the material's properties, parameters of the forming process, surface topography of the sheet and tools, and lubrication conditions. During the stamping of the drawpieces there are zones differentiated in terms of stress and strain state, displacement speed and friction conditions. This article describes the methods for determining the value of the coefficient of friction in selected areas of sheet metal and presents the drawbacks and limitations of these methods.

Surrogate POD Models for Parametrized Sheet Metal Forming Applications

2013 ◽  
Vol 554-557 ◽  
pp. 919-927 ◽  
Author(s):  
Hamdaoui Mohamed ◽  
Guénhaël Le Quilliec ◽  
Piotr Breitkopf ◽  
Pierre Villon
Keyword(s):  
Finite Element ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Optimization Problems ◽  
Strain Tensor ◽  
Forming Limit ◽  
Work Piece ◽  
Displacement Fields ◽  
Lagrange Strain

The aim of this work is to present a POD (Proper Orthogonal Decomposition) based surrogate approach for sheet metal forming parametrized applications. The final displacement field for the stamped work-piece computed using a finite element approach is approximated using the method of snapshots for POD mode determination and kriging for POD coefficients interpolation. An error analysis, performed using a validation set, shows that the accuracy of the surrogate POD model is excellent for the representation of finite element displacement fields. A possible use of the surrogate to assess the quality of the stamped sheet is considered. The Green-Lagrange strain tensor is derived and forming limit diagrams are computed on the fly for any point of the design space. Furthermore, the minimization of a cost function based on the surrogate POD model is performed showing its potential for solving optimization problems.

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