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

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