Calculation of forming limit curve for grade 2 titanium using modified sample geometry

by

Calculation of forming limit curve for grade 2 titanium using modified sample geometry

Julita Winowiecka, Piotr Lacki

Czestochowa University of Technology, Dąbrowskiego 69, 42-202 Czestochowa.

DOI:

https://doi.org/10.7494/cmms.2015.1.0500

Abstract:

Commercially pure titanium Grade 2 has good drawability and tensile strength of about 340 MPa. It is the most widespread grade of titanium in the industry. Grade 2 is characterized by good strength properties, low density, corrosion and external factors resistance. It is widely used in chemical, automotive and aerospace industries. In the aerospace industry titanium Grade 2 is used for production of fuselages, stringers, ventilating ducts, and many other parts. The subject of the work is the forming limit curve (FLC) widely used in industry to determine the possibility of the occurrence of draw-parts defects. FLC is determined based on the relationship between minor and major strains. It is a representation of the limit strains in the plane of the sheets, which, in order to avoid cracks, cannot be exceeded during sheet-metal forming. In the study forming limit curve was determined experimentally and the results were compared with the principal strain calculated in numerical simulations. Numerical simulations of the sheet – metal forming process were prepared in the PamStamp 2G v2012 program, using the finite element method. Forming simulation was carried out for specially designed samples with different lateral cut. The results of experimental studies at a depth corresponding to crack onset were compared with numerical calculations. Distributions of principal strain were determined for all specimens. The minor and major principal strains occurring in the forming samples before rupture onset were analyzed. Based on the results of numerical investigations forming limit curve for the titanium Grade 2 was determined. In experimental studies, in order to determine the plastic deformation ARAMIS system was used that enables non-contact measurements of threedimensional deformations. The PamStamp 2G program and ARAMIS data acquisition process allowed for analysis of deformation and determination of the values of minor and major principal strains immediately before rupture. The numerical simulations considered technically dry friction and lubrication. This approach allowed for determining the effect of lubrication on strain distributions.

Cite as:

Winowiecka, J., & Lacki, P. (2015). Calculation of forming limit curve for grade 2 titanium using modified sample geometry. Computer Methods in Materials Science, 15(1), 37-43. https://doi.org/10.7494/cmms.2015.1.0500

Article (PDF):

Keywords:

Finite element method, Titanium grade 2, Forming limit curve

Publication dates:

Received: 30.09.2014, accepted: 02.12.2014, published: 28.12.2014

Publication type:

Original scientific paper

References:

GOM mbH, ARAMIS, ARGUS, SVIEW – FLC Computation v6.1.1 and higher, 2009.

GOM mbH, ARAMIS v6.3 and higher – User Manual, 2011.

Adamus, J., 2009a, Theoretical and experimental analysis of the sheet-titanium forming process, Archives of Metallurgy and Materials 54 (3), 705–709.

Adamus, J., 2009b, Titanium and its alloys as a material used for the drawn-parts, Inżynieria Materiałowa 30, 310–313.

Adamus, J.,Lacki, P., 2014, Analysis of forming titanium welded blanks, Computational Materials Science.

Adamus, J., Lacki, P., Łyźniak, J.,Motyka, M., 2011, Optimization of the stamping process of a deflector element made of titanium Grade 2, Rudy i Metale Nieżelazne 56 (11), pp. 588–593.

Ávila, A. F.,Vieira, E. L.S., 2003, Proposing a better forming limit diagram prediction: a comparative study, Journal of Materials Processing Technology 141,101–108.

Badr, O.M. , Rolfe, B. , Hodgson, P. , Weiss, M., 2014, Forming of high strength titanium sheet at room temperature, Materials and Design, In Press.

Banabic, D., 2010, A review on recent developments of Marciniak-Kuczyński model, Computer Methods in Materials Science, 10, 225-237.

Butuc, M. C., Gracio, J. J.,Barata da Rocha, A., 2003, A theoretical study on forming limit diagrams prediction, Journal of Materials Processing Technology 142, 714–724.

Djavanroodi, F.,Derogar, A., 2010, Experimental and numerical evaluation of forming limit diagram for Ti6Al4V titanium and Al6061-T6 aluminum alloys sheets, Materials & Design 31, 4866–4875.

Dong, W.-Q. , Zhang, X.-L., 2014, Experimental study on the forming limit diagrams (FLD) of aerospace sheet metal materials, Journal of Plasticity Engineering 21, 41-45.

Goodwin, G. M., 1968, Application of strain analysis to sheet metal forming problems in the press shop., Metall Italiana 60, 764–774.

Hecker, S. S., 1975, Simple technique for determining forming limit curves., Sheet Metal Ind. 53, 671–675.
Hogström, P., Ringsberg, J. W.,Johnson, E., 2009, An experimental and numerical study of the effects of length scale and strain state on the necking and fracture behaviours in sheet metals, International Journal of Impact Engineering 36, 1194–1203.

Keeler, S. P., 1965, Determination of forming limits in automotive stampings, Sheet Metal Ind. 42, 683-691.
Lacki, P., Adamus, J., Więckowski, W.,Winowiecka, J., 2013, Evaluation of drawability of titanium welded sheets, Archives of Metallurgy and Materials 58, 139–143.

Marciniak, Z., Kuczyński, K., 1967, Limit strains in the process of stretch-forming sheet metal, International Journal of Mechanical Sciences, 9, 609-620.

Marciniak, Z., Duncan, J.L. and Hu, S.J., 2002, Mechanics of sheet metal forming. London: Butterworth-Heinemann.
Narayanasamy, R.,Narayanan, C. Sathiya, 2006, Forming limit diagram for Indian interstitial free steels, Materials & Design 27, 882–899.

Narayanasamy, R.,Narayanan, C. Sathiya, 2008, Forming, fracture and wrinkling limit diagram for if steel sheets of different thickness, Materials & Design 29, 1467–1475.

Oh, K. S., Oh, K. H., Jang, J. H., Kim, D. J. ,Han, K. S., 2011, Design and analysis of new test method for evaluation of sheet metal formability, Journal of Materials Processing Technology 211, 695–707.

Situ, Q., Jain, M. K.,Metzger, D. R., 2011, Determination of forming limit diagrams of sheet materials with a hybrid experimental–numerical approach, International Journal of Mechanical Sciences 53, 707–719.

Winowiecka, J., 2013, The analysis of springback of titanium sheet after bending, Obróbka Plastyczna Metali XXIV, 219–231.

Winowiecka, J., Więckowski, W., Lacki, P.,Adamus, J., 2014, Numeryczno-doświadczalna analiza procesu tłoczenia spawanych blach tytanowych, Rudy i Metale Nieżelazne 59, 173–181.

Winowiecka, J., Więckowski, W.,Zawadzki, M., 2013, Evaluation of drawability of tailor-welded blanks made of titanium alloys grade 2 || grade 5, Computational Materials Science 77, 108–113.